PIMCO VARIABLE INSURANCE TRUST
497, 2000-05-01
Previous: TELIGENT INC, DEF 14A, 2000-05-01
Next: BARBEQUES GALORE LTD, 20-F, 2000-05-01



<PAGE>

[LOGO]              PIMCO Funds Prospectus

PIMCO               ------------------------------------------------------------
Variable            SHORT DURATION BOND PORTFOLIO
Insurance           Low Duration Bond Portfolio
Trust
                    ------------------------------------------------------------
April 1, 2000       INTERMEDIATE DURATION BOND PORTFOLIOS
                    Total Return Bond Portfolio
Share Class         High Yield Bond Portfolio

                    ------------------------------------------------------------
                    STOCK PORTFOLIO
                    StocksPLUS Growth and Income Portfolio


Adm Administrative  This cover is not part of the Prospectus

                                                           [LOGO OF PIMCO FUNDS]


<PAGE>

            Prospectus


PIMCO       This Prospectus describes 4 separate investment portfolios (the
Variable    "Portfolios"), offered by the PIMCO Variable Insurance Trust (the
Insurance   "Trust"). The Portfolios provide access to the professional
Trust       investment management services offered by Pacific Investment
            Management Company ("PIMCO"). The investments made by the
April 1,    Portfolios at any given time are not expected to be the same as
2000        those made by other mutual funds for which PIMCO acts as
            investment adviser, including mutual funds with investment
Share       objectives and strategies similar to those of the Portfolios.
Class       Accordingly, the performance of the Portfolios can be expected to
Adminis-    vary from that of the other mutual funds.
trative

            This Prospectus explains what you should know about the Portfolios
            before you invest. Please read it carefully.

            Shares of the Portfolios currently are sold to segregated asset
            accounts ("Separate Accounts") of insurance companies that fund
            variable annuity contracts and variable life insurance policies
            ("Variable Contracts"). Assets in the Separate Account are
            invested in shares of the Portfolios in accordance with allocation
            instructions received from owners of the Variable Contracts
            ("Variable Contract Owners"). Variable Contract Owners do not deal
            directly with the Portfolios to purchase or redeem shares. The
            allocation rights of Variable Contract Owners are described in the
            accompanying Separate Account prospectus. Shares of the Portfolios
            also may be sold to qualified pension and retirement plans outside
            of the separate account context.

            This Prospectus should be read in conjunction with the prospectus
            of the Separate Account. Both prospectuses should be read
            carefully and retained for future reference.

            The Securities and Exchange Commission has not approved or
            disapproved these securities, or determined if this Prospectus is
            truthful or complete. Any representation to the contrary is a
            criminal offense.

   PIMCO Variable Insurance Trust
1
<PAGE>

            Table of Contents

<TABLE>
         <S>                                                               <C>
         Summary Information..............................................   3
         Portfolio Summaries..............................................   5
           Low Duration Bond Portfolio....................................   5
           Total Return Bond Portfolio....................................   7
           High Yield Bond Portfolio......................................   9
           StocksPLUS Growth and Income Portfolio.........................  11
         Summary of Principal Risks.......................................  13
         Management of the Portfolios.....................................  16
         Investment Options...............................................  17
         Purchases and Redemptions........................................  18
         How Portfolio Shares are Priced..................................  19
         Tax Consequences.................................................  20
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  21
         Financial Highlights.............................................  30
         Appendix A--Description of Securities Ratings.................... A-1
</TABLE>

                                                                  Prospectus
                                                                               2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                                  Non-U.S.
                                                                                                  Dollar
                                                                                Credit            Denominated
                                            Main Investments          Duration  Quality(1)        Securities(2)
- ---------------------------------------------------------------------------------------------------------------
 <C>           <C>                          <S>                       <C>       <C>               <C>
 Short         Low Duration Bond            Short maturity fixed      1-3 years B to Aaa; max 10%   0-20%(3)
 Duration                                   income securities                   below Baa
 Bond
 Portfolio
- ---------------------------------------------------------------------------------------------------------------
 Intermediate  Total Return Bond            Intermediate maturity     3-6 years B to Aaa; max 10%   0-20%(3)
 Duration                                   fixed income securities             below Baa
 Bond
 Portfolios
         ------------------------------------------------------------------------------------------------------
               High Yield Bond              Higher yielding fixed     2-6 years B to Aaa; min 65%   0-15%(4)
                                            income securities                   below Baa
- ---------------------------------------------------------------------------------------------------------------
 Stock         StocksPLUS Growth and Income S&P 500 stock index       0-1 year  B to Aaa; max       0-20%(3)
 Portfolio                                  derivatives backed by a             10% below Baa
                                            portfolio of short-term
                                            fixed-income securities
- ---------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  Each Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.
(4)  The percentage limitation relates to euro-denominated securities.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)
Fixed       The "Fixed Income Portfolios" are the Low Duration Bond, Total
Income      Return Bond, and High Yield Bond Portfolios. Each of the Fixed
Instruments Income Portfolios differs from the others primarily in the length
            of the Portfolio's duration or the proportion of its investments
            in certain types of fixed income securities. Each Fixed Income
            Portfolio invests at least 65% of its assets in "Fixed Income
            Instruments," which as used in this Prospectus includes:

            . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio   The Portfolios provide a broad range of investment choices. The
Descrip-    following summaries identify each Portfolio's investment
tions,      objective, principal investments and strategies, principal risks,
Per-        performance information and fees and expenses. A more detailed
formance    "Summary of Principal Risks" describing principal risks of
and Fees    investing in the Portfolios begins after the Portfolio Summaries.

             It is possible to lose money on investments in the Portfolios.

             An investment in a Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.

                                                                  Prospectus
                                                                               4
<PAGE>

            PIMCO Low Duration Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Short maturity       B to Aaa; maximum
and           Seeks maximum          fixed income         10% below Baa
Strategies    total return,          securities
              consistent with                             Dividend Frequency
              preservation of        Average Portfolio    Declared daily and
              capital and            Duration             distributed monthly
              prudent                1-3 years
              investment
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a one- to three-year time frame based on
            PIMCO's forecast for interest rates.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P, or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Derivatives Risk    .  Currency Risk
                 Risk                .  Liquidity Risk      .  Leveraging
              .  Credit Risk         .  Mortgage Risk          Risk
              .  Market Risk         .  Foreign             .  Management
              .  Issuer Risk            Investment             Risk
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.

5  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Low Duration Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
         ----------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.25%    0.15%   0.38%(1) 0.78%               (0.13%)      0.65%
         ----------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.13%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class                         Year 1                                         Year 3
         -----------------------------------------------------------------------------------------
         <S>                                 <C>                                            <C>
         Administrative                      $66                                            $236
         -----------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>

            PIMCO Total Return Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Intermediate         B to Aaa; maximum
and           Seeks maximum          maturity fixed       10% below Baa
Strategies    total return,          income
              consistent with        securities           Dividend Frequency
              preservation of                             Declared daily and
              capital and            Average Portfolio    distributed monthly
              prudent                Duration
              investment             3-6 years
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a three- to six-year time frame based on
            PIMCO's forecast for interest rates.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Derivatives         .  Currency Risk
                 Risk                   Risk                .  Leveraging
              .  Credit Risk         .  Liquidity Risk         Risk
              .  Market Risk         .  Mortgage Risk       .  Management
              .  Issuer Risk         .  Foreign                Risk
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


7  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Total Return Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

                                          Highest and Lowest Quarter Returns
                                          (for periods shown in the bar chart)
                                          --------------------
                                          Highest (3rd Qtr. '98)5.43%
                                          --------------------
    [GRAPH]                               Lowest (2nd Qtr. '99)(0.94%)

1998      8.61%
1999     -0.58%


                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                         1 Year  (12/31/97)
            -----------------------------------------------
         <S>                             <C>     <C>
         Administrative Class            (0.58%) 3.91%
            -----------------------------------------------
         Lehman Aggregate Bond Index(1)  (0.82%) 3.82%
            -----------------------------------------------
</TABLE>

            (1) The Lehman Brothers Aggregate Bond Index is an unmanaged index
                of investment grade, U.S. dollar-denominated fixed income
                securities of domestic issuers having a maturity greater than
                one year. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and
Expenses    These tables describe the fees and expenses you may pay if you buy
of the      and hold Administrative Class shares of the Portfolio:
Portfolio
            Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual
                                                   Portfolio                 Net Portfolio
                         Advisory Service Other    Operating    Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses     Reduction(2) Expenses
            ------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>          <C>          <C>
         Administrative  0.25%    0.15%   0.29%(1) 0.69%        (0.04%)      0.65%
            ------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.04%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $217               $380               $855
            -----------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   8
<PAGE>

            PIMCO High Yield Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Higher yielding      B to Aaa; minimum
and           Seeks maximum          fixed income         65% below Baa
Strategies    total return,          securities
              consistent with                             Dividend Frequency
              preservation of        Average Portfolio    Declared daily and
              capital and            Duration             distributed monthly
              prudent                2-6 years
              investment
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of high yield securities ("junk bonds")
            rated below investment grade but rated at least B by Moody's or
            S&P, or, if unrated, determined by PIMCO to be of comparable
            quality. The remainder of the Portfolio's assets may be invested
            in investment grade Fixed Income Instruments. The average
            portfolio duration of this Portfolio normally varies within a two-
            to six-year time frame based on PIMCO's forecast for interest
            rates. The Portfolio may invest without limit in U.S. dollar-
            denominated securities of foreign issuers. The Portfolio may
            invest up to 15% of its assets in euro-denominated securities. The
            Portfolio normally will hedge at least 75% of its exposure to the
            euro to reduce the risk of loss due to fluctuations in currency
            exchange rates.

             The Portfolio may invest up to 15% of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements. The Portfolio may invest all of its assets in
            mortgage- or asset-backed securities. The Portfolio may lend its
            portfolio securities to brokers, dealers, and other financial
            institutions to earn income. The Portfolio may seek to obtain
            market exposure to the securities in which it primarily invests by
            entering into a series of purchase and sale contracts or by using
            other investment techniques (such as buy backs or dollar rolls).
            The "total return" sought by the Portfolio consists of income
            earned on the Portfolio's investments, plus capital appreciation,
            if any, which generally arises from decreases in interest rates or
            improving credit fundamentals for a particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Issuer Risk         .  Foreign
                 Risk                .  Liquidity Risk         Investment Risk
              .  Credit Risk         .  Derivatives Risk    .  Currency Risk
              .  High Yield Risk     .  Mortgage Risk       .  Leveraging Risk
              .  Market Risk                                .  Management Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


9
   PIMCO Variable Insurance Trust
<PAGE>

            PIMCO High Yield Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

                                           Highest and Lowest Quarter Returns
                                           (for periods shown in the bar chart)
                                           --------------------
   [GRAPH]                                 Highest (1st Qtr.'99)2.00%
                                           --------------------
1999     3.01%                             Lowest (2nd Qtr.'99)(0.51%)


                   Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                          1 Year (04/30/98)
            -----------------------------------------------
         <S>                              <C>    <C>
         Administrative Class             3.01%  2.88%
            -----------------------------------------------
         Lehman Brothers BB Intermediate
          Corporate Index(1)              2.20%  3.02%
            -----------------------------------------------
</TABLE>

            (1) The Lehman Brothers BB Intermediate Corporate Index is an
                unmanaged index comprised of various fixed income securities
                rated BB with an average duration of 4.40 years as of
                12/31/99. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.25%    0.15%   0.35%(1) 0.75%               0.00%        0.75%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.35% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.75% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $77                $240               $417               $930
            -----------------------------------------------------------------------------------
</TABLE>

                                                                 Prospectus   10
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              S&P 500 stock        B to Aaa; maximum
and                                  index derivatives    10% below Baa
Strategies                           backed by a
              Seeks total            portfolio of         Dividend
              return which           short-term fixed     Frequency
              exceeds that of        income securities    Declared and
              the S&P 500                                 distributed
                                                          quarterly

                                     Average Portfolio
                                     Duration
                                     0-1 year

            The Portfolio seeks to exceed the total return of the S&P 500 by
            investing under normal circumstances substantially all of its
            assets in S&P 500 derivatives, backed by a portfolio of Fixed
            Income Instruments. The Portfolio may invest in common stocks,
            options, futures, options on futures and swaps. The Portfolio uses
            S&P 500 derivatives in addition to or in place of S&P 500 stocks
            to attempt to equal or exceed the performance of the S&P 500. The
            value of S&P 500 derivatives closely track changes in the value of
            the index. However, S&P 500 derivatives may be purchased with a
            fraction of the assets that would be needed to purchase the equity
            securities directly, so that the remainder of the assets may be
            invested in Fixed Income Instruments. PIMCO actively manages the
            fixed income assets held by the Portfolio with a view toward
            enhancing the Portfolio's total return, subject to an overall
            portfolio duration which is normally not expected to exceed one
            year.

             The S&P 500 is composed of 500 selected common stocks that
            represent approximately two-thirds of the total market value of
            all U.S. common stocks. The Portfolio is neither sponsored by nor
            affiliated with S&P. The Portfolio seeks to remain invested in S&P
            500 derivatives or S&P 500 stocks even when the S&P 500 is
            declining.

             Though the Portfolio does not normally invest directly in S&P 500
            securities, when S&P 500 derivatives appear to be overvalued
            relative to the S&P 500, the Portfolio may invest all of its
            assets in a "basket" of S&P 500 stocks. Individual stocks are
            selected based on an analysis of the historical correlation
            between the return of every S&P 500 stock and the return on the
            S&P 500 itself. PIMCO may employ fundamental analysis of factors
            such as earnings and earnings growth, price to earnings ratio,
            dividend growth, and cash flows to choose among stocks that
            satisfy the correlation tests. Stocks chosen for the Portfolio are
            not limited to those with any particular weighting in the S&P 500.
            The Portfolio may also invest in exchange traded funds based on
            the S&P 500, such as Standard & Poor's Depositary Receipt.

             Assets not invested in equity securities or derivatives may be
            invested in Fixed Income Instruments. The Portfolio may invest up
            to 10% of its assets in high yield securities ("junk bonds") rated
            B or higher by Moody's or S&P, or, if unrated, determined by PIMCO
            to be of comparable quality. The Portfolio may invest up to 20% of
            its assets in securities denominated in foreign currencies and may
            invest beyond this limit in U.S. dollar denominated securities of
            foreign issuers. The Portfolio will normally hedge at least 75% of
            its exposure to foreign currency to reduce the risk of loss due to
            fluctuations in currency exchange rates. In addition, the
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income.

- --------------------------------------------------------------------------------
Principal   Under certain conditions, generally in a market where the value of
Risks       both S&P 500 derivatives and fixed income securities are
            declining, the Portfolio may experience greater losses than would
            be the case if it invested directly in a portfolio of S&P 500
            stocks. Among the principal risks of investing in the Portfolio,
            which could adversely affect its net asset value, yield and total
            return, are:

              . Market Risk          . Interest Rate        . Mortgage Risk
              . Issuer Risk             Risk                . Leveraging Risk
              . Derivatives Risk     . Liquidity Risk       . Management Risk
              . Credit Risk          . Foreign
                                        Investment
                                        Risk
                                     . Currency Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.

11 PIMCO Variable Insurance Trust
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

                                           Highest and Lowest Quarter Returns
                                           (for periods shown in the bar chart)
                                           --------------------
                                           Highest (4th Qtr. '98)21.95%
   [GRAPH]                                 --------------------
                                           Lowest (3rd Qtr. '98)-8.82%
1998     30.11%
1999     19.85%


                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)
<TABLE>
<CAPTION>
                                                                                   Portfolio
                                                                                   Inception
                                              1 Year                               (12/31/97)
            ---------------------------------------------------------------------------------
         <S>                                  <C>                                  <C>
         Administrative Class                 19.85%                               24.87%
            ---------------------------------------------------------------------------------
         S&P 500 Index(1)                     21.04%                               24.75%
            ---------------------------------------------------------------------------------
</TABLE>

            (1) The Standard & Poor's 500 Composite Stock Price Index is an
                unmanaged index of common stocks. It is not possible to invest
                directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.40%    0.15%   0.10%(1) 0.65%               0.00%        0.65%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.10% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operation expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $208               $362               $810
            -----------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus  12
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

High        Portfolios that invest in high yield securities and unrated
Yield       securities of similar credit quality (commonly known as "junk
Risk        bonds") may be subject to greater levels of interest rate, credit
            and liquidity risk than Portfolios that do not invest in such
            securities. High yield securities are considered predominately
            speculative with respect to the issuer's continuing ability to
            make principal and interest payments. An economic downturn or
            period of rising interest rates could adversely affect the market
            for high yield securities and reduce a Portfolio's ability to sell
            its high yield securities (liquidity risk).

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

   PIMCO Variable Insurance Trust
13
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolios may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    Portfolios that invest directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies are subject to the risk that those currencies
            will decline in value relative to the U.S. dollar, or, in the case
            of hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary

                                                                  Prospectus
                                                                              14
<PAGE>

            Fund, or by the imposition of currency controls or other political
            developments in the U.S. or abroad. As a result, a Portfolio's
            investments in foreign currency-denominated securities may reduce
            the returns of a Portfolio.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

   PIMCO Variable Insurance Trust
15
<PAGE>

            Management of the Portfolios

Invest-     PIMCO serves as investment adviser and the administrator (serving
ment        in its capacity as administrator, the "Administrator") for the
Adviser     Portfolios. Subject to the supervision of the Board of Trustees,
and         PIMCO is responsible for managing the investment activities of the
Adminis-    Portfolios and the Portfolios' business affairs and other
trator      administrative matters.

             PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
            Beach, California 92660. Organized in 1971, PIMCO provides
            investment management and advisory services to private accounts of
            institutional and individual clients and to mutual funds. As of
            December 31, 1999, PIMCO had approximately $186 billion in assets
            under management.

Advisory    Each Portfolio pays PIMCO fees in return for providing investment
Fees        advisory services. For the fiscal year ended December 31, 1999,
            the Portfolios paid monthly advisory fees to PIMCO at the
            following annual rates (stated as a percentage of the average
            daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio                                              Advisory Fees
         --------------------------------------------------------------------
         <S>                                                    <C>
         High Yield Bond Portfolio                                  0.50%
         All other Portfolios                                       0.40%
</TABLE>

             Effective April 1, 2000, the Portfolios pay monthly advisory fees
            to PIMCO at the following annual rates (stated as a percentage of
            the average daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio
                                                                Advisory Fees
         --------------------------------------------------------------------
         <S>                                                    <C>
         StocksPLUS Growth and Income Portfolio                     0.40%
         All other Portfolios                                       0.25%
</TABLE>

Administrative
Fees
            Each Portfolio pays for the administrative services it requires
            under a fee structure which is essentially fixed. Shareholders of
            each Portfolio pay an administrative fee to PIMCO, computed as a
            percentage of the Portfolio's assets attributable in the aggregate
            to that class of shares. PIMCO, in turn, provides or procures
            administrative services for shareholders and also bears the costs
            of various third-party services required by the Portfolios,
            including audit, custodial, portfolio accounting, legal, transfer
            agency and printing costs. The result of this fee structure is an
            expense level for shareholders of each Portfolio that, with
            limited exceptions, is precise and predictable under ordinary
            circumstances.

             For the fiscal year ended December 31, 1999, the Portfolios paid
            PIMCO monthly administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio                                       Administrative Fees
         -------------------------------------------------------------------
         <S>                                             <C>
         All Portfolios                                         0.25%
</TABLE>

             Effective April 1, 2000, the Portfolios pay PIMCO monthly
            administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio                                       Administrative Fees
         -------------------------------------------------------------------
         <S>                                             <C>
         StocksPLUS Growth & Income Portfolio                   0.10%
         High Yield Portfolio                                   0.35%
         All other Portfolios                                   0.25%
</TABLE>

                                                                  Prospectus
                                                                              16
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

<TABLE>
<CAPTION>
         Portfolio          Portfolio Manager  Since  Recent Professional Experience
         ---------------------------------------------------------------------------

         <C>                <C>                <C>    <S>
         Low Duration Bond  William H. Gross    2/99*  Managing Director, Chief
         Total Return Bond                     12/97*  Investment Officer and a
         StocksPLUS                                    founding partner of PIMCO.
          Growth and Income                    12/97*  He leads a team which
                                                       manages the StocksPLUS
                                                       Portfolio.




         High Yield Bond    Benjamin L. Trosky  4/98*  Managing Director, PIMCO. He
                                                       joined PIMCO as a Portfolio
                                                       Manager in 1990.

</TABLE>



            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

   PIMCO Variable Insurance Trust
17
<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of each Portfolio. The Plan allows the
            Portfolios to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits a Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of a Portfolio's Administrative Class assets on
            an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account

                                                                  Prospectus
                                                                              18
<PAGE>

            allocating assets to the Portfolios are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolios might be
            required to redeem the investment of one or more of its separate
            accounts from the Portfolios, which might force the Portfolios to
            sell securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolios to dispose of
            their securities or to determine fairly the value of their net
            assets, or during any other period as permitted by the SEC for the
            protection of investors. In the event that a Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Administrative Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.


19 PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus
                                                                              20
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  Most of the Portfolios in this prospectus seek maximum total
Selection   return. The total return sought by a Portfolio consists of both
            income earned on a Portfolio's investments and capital
            appreciation, if any, arising from increases in the market value
            of a Portfolio's holdings. Capital appreciation of fixed income
            securities generally results from decreases in market interest
            rates or improving credit fundamentals for a particular market
            sector or security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of a Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio may invest all of its assets in mortgage- and
Related     asset-backed securities. Mortgage-related securities include
and Other   mortgage pass-through securities, collateralized mortgage
Asset-      obligations ("CMOs"), commercial mortgage-backed securities,
Backed      mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities  securities ("SMBSs") and other securities that directly or
            indirectly represent a participation in, or are secured by and
            payable from, mortgage loans on real property.

   PIMCO Variable Insurance Trust
21
<PAGE>

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolios may
            invest in other asset-backed securities that have been offered to
            investors.

Loan        Certain Portfolios may invest in fixed- and floating-rate loans,
Participa-  which investments generally will be in the form of loan
tions       participations and assignments of portions of such loans.
and         Participations and assignments involve special types of risk,
Assign-     including credit risk, interest rate risk, liquidity risk, and the
ments       risks of being a lender. If a Portfolio purchases a participation,
            it may only be able to enforce its rights through the lender, and
            may assume the credit risk of the lender in addition to the
            borrower.

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

                                                                  Prospectus
                                                                              22
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

            Variable and floating rate securities provide for a periodic
Variable    adjustment in the interest rate paid on the obligations. Each
and         Portfolio may invest in floating rate debt instruments
Floating    ("floaters") and engage in credit spread trades. While floaters
Rate        provide a certain degree of protection against rises in interest
Securities  rates, a Portfolio will participate in any declines in interest
            rates as well. Each Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. A Portfolio may not invest more than 5% of
            its assets in any combination of inverse floater, interest only,
            or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      Each Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

   PIMCO Variable Insurance Trust
23
<PAGE>

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

            Investing in the securities of issuers in any foreign country
Foreign     involves special risks and considerations not typically associated
(Non-       with investing in U.S. companies. Shareholders should consider
U.S.)       carefully the substantial risks involved for Portfolios that
Securities  invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             Certain Portfolios also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. The Low Duration Bond Portfolio
            may invest up to 5% of its assets in securities of issuers based
            in countries with developing (or "emerging market") economies and
            each remaining Portfolio that may invest in foreign securities may
            invest up to 10% of its assets in such securities. Investing in
            emerging market securities imposes risks different from, or
            greater than, risks of investing in domestic securities or in
            foreign, developed countries. These risks include: smaller market
            capitalization of securities markets, which may suffer periods of
            relative illiquidity; significant price volatility; restrictions
            on foreign investment; possible repatriation of investment income
            and capital. In addition, foreign investors may be required to
            register the proceeds of sales; future economic or political
            crises could lead to price controls, forced mergers, expropriation
            or confiscatory taxation, seizure, nationalization, or creation of
            government monopolies. The currencies of emerging market countries
            may experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                Prospectus
                                                                              24
<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             Each Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolios' assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolios.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into
            forward foreign currency exchange contracts and invest in foreign
            currency futures contracts and options on foreign currencies and
            futures. A forward foreign currency exchange contract, which
            involves an obligation to purchase or sell a specific currency at
            a future date at a price set at the time of the contract, reduces
            a Portfolio's exposure to changes in the value of the currency it
            will deliver and increases its exposure
            to changes in the value of the currency it will receive for the
            duration of the contract. The effect on the value of a Portfolio
            is similar to selling securities denominated in one currency and
            purchasing securities denominated in another currency. A contract
            to sell foreign currency would limit any potential gain which
            might be realized if the value of the hedged currency increases. A
            Portfolio may enter into these contracts to hedge against foreign
            exchange risk, to increase exposure to a foreign currency or to
            shift exposure to foreign currency fluctuations from one currency
            to another. Suitable hedging transactions may not be available in
            all circumstances and there can be no assurance that a Portfolio
            will engage in such transactions at any given time or from time to
            time. Also, such transactions may not be successful and may
            eliminate any chance for a Portfolio to benefit from favorable
            fluctuations in relevant foreign currencies. A Portfolio may use
            one currency (or a basket of currencies) to hedge against adverse
            changes in the value of another currency (or a basket of
            currencies) when exchange rates between the two currencies are
            positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations
            under forward foreign currency exchange contracts entered into for
            non-hedging purposes.

Repurchase  Each Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


   PIMCO Variable Insurance Trust
25
<PAGE>

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. Each Portfolio may
            invest all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolios may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus
                                                                              26
<PAGE>

            each Portfolio will segregate assets determined to be liquid by
            PIMCO in accordance with procedures established by the Board of
            Trustees (or, as permitted by applicable regulation, enter into
            certain offsetting positions) to cover its obligations under
            derivative instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolios may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring a Portfolio to increase its investment in
Facilities  a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            a Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       Each Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Transactionssettlement date. This risk is in addition to the risk that the
            Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase a
            Portfolio's overall investment exposure. Typically, no income
            accrues on securities a Portfolio has committed to purchase prior
            to the time delivery of the securities is made, although a
            Portfolio may earn income on securities it has segregated to cover
            these positions.


   PIMCO Variable Insurance Trust
27
<PAGE>

Investment  Each Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, a Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, each
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       Each Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    Each Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.


                                                                   Prospectus
                                                                              28
<PAGE>

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

   PIMCO Variable Insurance Trust
29
<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                  Prospectus
                                                                              30
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Low Duration
 Administrative Class
 12/31/1999(b)         $10.00     $0.50        $(0.25)(a)    $ 0.25      $(0.51)     $ 0.00        $ 0.00         $0.00
Total Return
 Administrative Class
 12/31/1999            $10.09     $0.58        $(0.64)(a)    $(0.06)     $(0.58)     $ 0.00        $ 0.00         $0.00
 12/31/1998(e)          10.00      0.56          0.28 (a)      0.84       (0.56)       0.00         (0.19)         0.00
High Yield
 Administrative Class
 12/31/1999            $ 9.67     $0.77        $(0.49)(a)    $ 0.28      $(0.77)     $ 0.00        $ 0.00         $0.00
 12/31/1998(f)          10.00      0.51         (0.34)(a)      0.17       (0.50)       0.00          0.00          0.00
StocksPLUS Growth and Income
 Administrative Class
 12/31/1999            $12.58     $0.76        $ 1.65 (a)    $ 2.41      $(0.61)     $(0.82)       $ 0.00         $0.00
 12/31/1998(e)          10.00      0.30          2.68 (a)      2.98       (0.29)      (0.11)         0.00          0.00
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(b) Commenced operations on February 16, 1999.
(e) Commenced operations on December 31, 1997.
(f) Commenced operations on April 30, 1998.

   PIMCO Variable Insurance Trust
31
<PAGE>




<TABLE>
<CAPTION>
                                                                     Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of      Investment
 Return                    Value               End     Expenses to    Income to   Portfolio
   of          Total        End    Total    of Period    Average       Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets     Net Assets    Rate
- -------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>           <C>          <C>


  $0.00       $(0.51)     $ 9.74    2.56 %   $  5,149     0.65%*(c)      5.74%*       11%


  $0.00       $(0.58)     $ 9.45   (0.58)%   $  3,877     0.65% (d)      5.96%       102%
   0.00        (0.75)      10.09    8.61        3,259     0.65           5.55        139


  $0.00       $(0.77)     $ 9.18    3.01 %   $151,020     0.75%          8.25%        13%
   0.00        (0.50)       9.67    1.80       49,761     0.75           7.90*        13


  $0.00       $(1.43)     $13.56   19.85 %   $230,412     0.65%          5.69%        34%
   0.00        (0.40)      12.58   30.11       58,264     0.65           5.30         61
</TABLE>
- -------
*   Annualized.
(c) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.78%* for the
    period ended December 31, 1999.
(d) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.69% for the
    period ended December 31, 1999.

                                                                  Prospectus
                                                                              32
<PAGE>

            Other Information


Performance The following table provides information concerning the historical
Information total return performance of the Institutional Class shares of
of          certain series of PIMCO Funds: Pacific Investment Management
Similar     Series ("PIMS"). Each PIMS series has investment objectives,
Funds       policies and strategies substantially similar to those of its
            respective PIMCO Variable Insurance Trust ("PVIT") Portfolio and
            is currently managed by the same portfolio manager. While the
            investment objectives and policies of each PIMS series and its
            respective PVIT Portfolio are similar, they are not identical and
            the performance of the PIMS series and the PVIT Portfolio will
            vary. The data is provided to illustrate the past performance of
            PIMCO in managing a substantially similar investment portfolio and
            does not represent the past performance of any of the PVIT
            Portfolios or the future performance of any PVIT Portfolio or its
            portfolio manager. Consequently, potential investors should not
            consider this performance data as an indication of the future
            performance of any PVIT Portfolio or of its portfolio manager.

            The performance data shown below reflects the operating expenses
            of the Institutional Class of the PIMS series. The operating
            expenses for the Institutional Class of the PIMS Low Duration Fund
            are lower than the operating expenses for the Institutional Class
            of the corresponding PVIT Portfolio. Furthermore, the operating
            expenses of the Institutional Class of each PIMS series in the
            table are lower than the operating expenses of each Administrative
            Class of the corresponding PVIT Portfolio. As such, performance
            would have been lower if the PVIT Portfolio's expenses were used.
            In addition, the PIMS series, unlike the Portfolios, are not sold
            to Separate Accounts to fund Variable Contracts. As a result, the
            performance results presented below do not take into account
            charges or deductions against a Separate Account or Variable
            Contract for cost of insurance charges, premium loads,
            administrative fees, maintenance fees, premium taxes, mortality
            and expense risk charges, or other charges that may be incurred
            under a Variable Contract for which the Portfolio serves as an
            underlying investment vehicle. By contrast, Variable Contract
            Owners with contract value allocated to the Portfolios will be
            subject to charges and expenses relating to the Variable Contracts
            and Separate Accounts.

            Each PIMS series' performance data shown below is calculated in
            accordance with standards prescribed by the SEC for the
            calculation of average annual total return information. The
            investment results of the PIMS series presented below are
            unaudited and are not intended to predict or suggest results that
            might be experienced by the PIMS series or the Portfolios. Share
            prices and investment returns will fluctuate reflecting market
            conditions, as well as changes in company-specific fundamentals of
            portfolio securities. The performance data for the benchmark
            indices identified below does not reflect the fees or expenses of
            the PIMS series or the Portfolios.

   Average Annual Total Return for Similar Series of PIMS Institutional Class
         and for Benchmark Indices for Periods Ended December 31, 1999

<TABLE>
<CAPTION>
                                                            Since   Inception
                                   1 Year 3 Years 5 Years Inception   Date
- -----------------------------------------------------------------------------
<S>                                <C>    <C>     <C>     <C>       <C>
PIMCO Low Duration Fund             2.97   6.10    7.25     7.80     5/11/87
 Merrill Lynch 1-3 yr. Treasury/1/  3.06   5.56    6.51
</TABLE>
- -------
/1/The Merrill Lynch 1-3 Year Treasury Index consists of all public U.S.
  Treasury obligations having maturities from one to 2.99 years. It is not
  possible to invest directly in the index.

   PIMCO Variable Insurance Trust
33
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

                                                                  Prospectus
                                                                             A-1
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

   PIMCO Variable Insurance Trust
A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

                                                                  Prospectus
                                                                             A-3
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

   PIMCO Variable Insurance Trust
A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington, D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.

[LOGO OF PIMCO FUNDS]

PIMCO Funds
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

<PAGE>

PIMCO Funds Prospectus


PIMCO Variable Insurance Trust

April 1, 2000

Share Class

Adm Administrative
- --------------------------------------------------------------------------------
INTERMEDIATE DURATION BOND PORTFOLIOS
Total Return Bond Portfolio
High Yield Bond Portfolio

- --------------------------------------------------------------------------------

STOCK PORTFOLIOS
StocksPLUS Growth and Income Portfolio



   This cover is not part of the Prospectus
                                                           [LOGO OF PIMCO FUNDS]


<PAGE>

            Prospectus


PIMCO           This Prospectus describes 3 separate investment portfolios (the
Variable        "Portfolios"), offered by the PIMCO Variable Insurance Trust
Insurance       (the "Trust"). The Portfolios provide access to the professional
Trust           investment management services offered by Pacific Investment
                Management Company ("PIMCO"). The investments made by the
April 1,        Portfolios at any given time are not expected to be the same as
2000            those made by other mutual funds for which PIMCO acts as
                investment adviser, including mutual funds with investment
Share           objectives and strategies similar to those of the Portfolios.
Class           Accordingly, the performance of the Portfolios can be expected
Administrative  to vary from that of the other mutual funds.

                This Prospectus explains what you should know about the
                Portfolios before you invest. Please read it carefully.

                Shares of the Portfolios currently are sold to segregated asset
                accounts ("Separate Accounts") of insurance companies that fund
                variable annuity contracts and variable life insurance policies
                ("Variable Contracts"). Assets in the Separate Account are
                invested in shares of the Portfolios in accordance with
                allocation instructions received from owners of the Variable
                Contracts ("Variable Contract Owners"). Variable Contract Owners
                do not deal directly with the Portfolios to purchase or redeem
                shares. The allocation rights of Variable Contract Owners are
                described in the accompanying Separate Account prospectus.
                Shares of the Portfolios also may be sold to qualified pension
                and retirement plans outside of the separate account context.

                This Prospectus should be read in conjunction with the
                prospectus of the Separate Account. Both prospectuses should be
                read carefully and retained for future reference.

                The Securities and Exchange Commission has not approved or
                disapproved these securities, or determined if this Prospectus
                is truthful or complete. Any representation to the contrary is a
                criminal offense.

1 PIMCO Variable Insurance Trust
<PAGE>

            Table of Contents

         Summary Information..............................................   3
         Portfolio Summaries..............................................   5
           Total Return Bond Portfolio....................................   5
           High Yield Bond Portfolio......................................   7
           StocksPLUS Growth and Income Portfolio.........................   9
         Summary of Principal Risks.......................................  11
         Management of the Portfolios.....................................  14
         Investment Options...............................................  15
         Purchases and Redemptions........................................  16
         How Portfolio Shares are Priced..................................  17
         Tax Consequences.................................................  18
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  19
         Financial Highlights.............................................  29
         Appendix A--Description of Securities Ratings.................... A-1

                                                                  Prospectus 2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                                  Non-U.S.
                                                                                                  Dollar
                                                                                Credit            Denominated
                                            Main Investments          Duration  Quality(1)        Securities(2)
- ---------------------------------------------------------------------------------------------------------------
 <C>           <C>                          <S>                       <C>       <C>               <C>
 Intermediate  Total Return Bond            Intermediate maturity     3-6 years B to Aaa; max 10%   0-20%(3)
 Duration                                   fixed income securities             below Baa
 Bond
 Portfolios
         ------------------------------------------------------------------------------------------------------
               High Yield Bond              Higher yielding fixed     2-6 years B to Aaa; min 65%   0-15%(4)
                                            income securities                   below Baa
- ---------------------------------------------------------------------------------------------------------------
 Stock         StocksPLUS Growth and Income S&P 500 stock index       0-1 year  B to Aaa; max       0-20%(3)
 Portfolio                                  derivatives backed by a             10% below Baa
                                            portfolio of short-term
                                            fixed-income securities
- ---------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  Each Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.
(4)  The percentage limitation relates to euro-denominated securities.

3  PIMCO Variable Insurance Trust
<PAGE>

               Summary Information (continued)
Fixed          The "Fixed Income Portfolios" are the Total Return Bond, and High
Income         Yield Bond Portfolios. Each of the Fixed Income Portfolios
Instruments    differs from the others primarily in the length of the
               Portfolio's duration or the proportion of its investments in
               certain types of fixed income securities. Each Fixed Income
               Portfolio invests at least 65% of its assets in "Fixed Income
               Instruments," which as used in this Prospectus includes:

               . securities issued or guaranteed by the U.S. Government, its
                 agencies or government-sponsored enterprises ("U.S. Government
                 Securities");
               . corporate debt securities of U.S. and non-U.S. issuers,
                 including convertible securities and corporate commercial
                 paper;
               . mortgage-backed and other asset-backed securities;
               . inflation-indexed bonds issued both by governments and
                 corporations;
               . structured notes, including hybrid or "indexed" securities,
                 event-linked bonds and loan participations;
               . delayed funding loans and revolving credit facilities;
               . bank certificates of deposit, fixed time deposits and bankers'
                 acceptances;
               . repurchase agreements and reverse repurchase agreements;
               . debt securities issued by states or local governments and their
                 agencies, authorities and other instrumentalities;
               . obligations of non-U.S. governments or their subdivisions,
                 agencies and instrumentalities; and
               . obligations of international agencies or supranational
                 entities.

Duration       Duration is a measure of the expected life of a fixed income
               security that is used to determine the sensitivity of a
               security's price to changes in interest rates. The longer a
               security's duration, the more sensitive it will be to changes in
               interest rates. Similarly, a Portfolio with a longer average
               portfolio duration will be more sensitive to changes in interest
               rates than a Portfolio with a shorter average portfolio duration.

Credit         In this Prospectus, references are made to credit ratings of debt
Ratings        securities which measure an issuer's expected ability to pay
               principal and interest on time. Credit ratings are determined by
               rating organizations, such as Standard & Poor's Rating Service
               ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
               following terms are generally used to describe the credit quality
               of debt securities depending on the security's credit rating or,
               if unrated, credit quality as determined by PIMCO:

               . high quality
               . investment grade
               . below investment grade ("high yield securities" or "junk
                 bonds")

                For a further description of credit ratings, see "Appendix A--
               Description of Securities Ratings."

Portfolio      The Portfolios provide a broad range of investment choices. The
Descriptions,  following summaries identify each Portfolio's investment
Performance    objective, principal investments and strategies, principal risks,
and Fees       performance information and fees and expenses. A more detailed
               "Summary of Principal Risks" describing principal risks of
               investing in the Portfolios begins after the Portfolio Summaries.

               It is possible to lose money on investments in the Portfolios.

                An investment in a Portfolio is not a deposit of a bank and is
               not guaranteed or insured by the Federal Deposit Insurance
               Corporation or any other government agency.

                                                                  Prospectus 4
<PAGE>

            PIMCO Total Return Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Intermediate         B to Aaa; maximum
and           Seeks maximum          maturity fixed       10% below Baa
Strategies    total return,          income
              consistent with        securities           Dividend Frequency
              preservation of                             Declared daily and
              capital and            Average Portfolio    distributed monthly
              prudent                Duration
              investment             3-6 years
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a three- to six-year time frame based on
            PIMCO's forecast for interest rates.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Derivatives         .  Currency Risk
                 Risk                   Risk                .  Leveraging
              .  Credit Risk         .  Liquidity Risk         Risk
              .  Market Risk         .  Mortgage Risk       .  Management
              .  Issuer Risk         .  Foreign                Risk
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


5  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Total Return Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

   [GRAPH]

'98      8.61%
'99     -0.58%

Highest and Lowest Quarter Returns
(for periods shown in the bar chart)
- --------------------
Highest (3rd Qtr. '98)5.43%
- --------------------
Lowest (2nd Qtr. '99)(0.94%)

                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                         1 Year  (12/31/97)
            -----------------------------------------------
         <S>                             <C>     <C>
         Administrative Class            (0.58%) 3.91%
            -----------------------------------------------
         Lehman Aggregate Bond Index(1)  (0.82%) 3.82%
            -----------------------------------------------
</TABLE>

            (1) The Lehman Brothers Aggregate Bond Index is an unmanaged index
                of investment grade, U.S. dollar-denominated fixed income
                securities of domestic issuers having a maturity greater than
                one year. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual
                                                   Portfolio                 Net Portfolio
                         Advisory Service Other    Operating    Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses     Reduction(2) Expenses
            ------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>          <C>          <C>
         Administrative  0.25%    0.15%   0.29%(1) 0.69%        (0.04%)      0.65%
            ------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.04%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $217               $380               $855
            -----------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>

            PIMCO High Yield Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Higher yielding      B to Aaa; minimum
and           Seeks maximum          fixed income         65% below Baa
Strategies    total return,          securities
              consistent with                             Dividend Frequency
              preservation of        Average Portfolio    Declared daily and
              capital and            Duration             distributed monthly
              prudent                2-6 years
              investment
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of high yield securities ("junk bonds")
            rated below investment grade but rated at least B by Moody's or
            S&P, or, if unrated, determined by PIMCO to be of comparable
            quality. The remainder of the Portfolio's assets may be invested
            in investment grade Fixed Income Instruments. The average
            portfolio duration of this Portfolio normally varies within a two-
            to six-year time frame based on PIMCO's forecast for interest
            rates. The Portfolio may invest without limit in U.S. dollar-
            denominated securities of foreign issuers. The Portfolio may
            invest up to 15% of its assets in euro-denominated securities. The
            Portfolio normally will hedge at least 75% of its exposure to the
            euro to reduce the risk of loss due to fluctuations in currency
            exchange rates.

             The Portfolio may invest up to 15% of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements. The Portfolio may invest all of its assets in
            mortgage- or asset-backed securities. The Portfolio may lend its
            portfolio securities to brokers, dealers, and other financial
            institutions to earn income. The Portfolio may seek to obtain
            market exposure to the securities in which it primarily invests by
            entering into a series of purchase and sale contracts or by using
            other investment techniques (such as buy backs or dollar rolls).
            The "total return" sought by the Portfolio consists of income
            earned on the Portfolio's investments, plus capital appreciation,
            if any, which generally arises from decreases in interest rates or
            improving credit fundamentals for a particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Issuer Risk         . Foreign
                 Risk                .  Liquidity Risk       Investment Risk
              .  Credit Risk         .  Derivatives Risk    .  Currency Risk
              .  High Yield Risk     .  Mortgage Risk       .  Leveraging Risk
              .  Market Risk                                .  Management Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


7 PIMCO Variable Insurance Trust
<PAGE>

            PIMCO High Yield Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

                                           Highest and Lowest Quarter Returns
                                           (for periods shown in the bar chart)
  [GRAPH]                                  --------------------
                                           Highest (1st Qtr.'99)2.00%
'99     3.01%                              --------------------
                                           Lowest (2nd Qtr.'99)(0.51%)

                   Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                          1 Year (04/30/98)
            -----------------------------------------------
         <S>                              <C>    <C>
         Administrative Class             3.01%  2.88%
            -----------------------------------------------
         Lehman Brothers BB Intermediate
          Corporate Index(1)              2.20%  3.02%
            -----------------------------------------------
</TABLE>

            (1) The Lehman Brothers BB Intermediate Corporate Index is an
                unmanaged index comprised of various fixed income securities
                rated BB with an average duration of 4.40 years as of
                12/31/99. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.25%    0.15%   0.35%(1) 0.75%               0.00%        0.75%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.35% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.75% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $77                $240               $417               $930
            -----------------------------------------------------------------------------------
</TABLE>

                                                                 Prospectus    8
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              S&P 500 stock        B to Aaa; maximum
and                                  index derivatives    10% below Baa
Strategies                           backed by a
              Seeks total            portfolio of         Dividend
              return which           short-term fixed     Frequency
              exceeds that of        income securities    Declared and
              the S&P 500                                 distributed
                                     Average Portfolio    quarterly
                                     Duration
                                     0-1 year


            The Portfolio seeks to exceed the total return of the S&P 500 by
            investing under normal circumstances substantially all of its
            assets in S&P 500 derivatives, backed by a portfolio of Fixed
            Income Instruments. The Portfolio may invest in common stocks,
            options, futures, options on futures and swaps. The Portfolio uses
            S&P 500 derivatives in addition to or in place of S&P 500 stocks
            to attempt to equal or exceed the performance of the S&P 500. The
            value of S&P 500 derivatives closely track changes in the value of
            the index. However, S&P 500 derivatives may be purchased with a
            fraction of the assets that would be needed to purchase the equity
            securities directly, so that the remainder of the assets may be
            invested in Fixed Income Instruments. PIMCO actively manages the
            fixed income assets held by the Portfolio with a view toward
            enhancing the Portfolio's total return, subject to an overall
            portfolio duration which is normally not expected to exceed one
            year.

             The S&P 500 is composed of 500 selected common stocks that
            represent approximately two-thirds of the total market value of
            all U.S. common stocks. The Portfolio is neither sponsored by nor
            affiliated with S&P. The Portfolio seeks to remain invested in S&P
            500 derivatives or S&P 500 stocks even when the S&P 500 is
            declining.

             Though the Portfolio does not normally invest directly in S&P 500
            securities, when S&P 500 derivatives appear to be overvalued
            relative to the S&P 500, the Portfolio may invest all of its
            assets in a "basket" of S&P 500 stocks. Individual stocks are
            selected based on an analysis of the historical correlation
            between the return of every S&P 500 stock and the return on the
            S&P 500 itself. PIMCO may employ fundamental analysis of factors
            such as earnings and earnings growth, price to earnings ratio,
            dividend growth, and cash flows to choose among stocks that
            satisfy the correlation tests. Stocks chosen for the Portfolio are
            not limited to those with any particular weighting in the S&P 500.
            The Portfolio may also invest in exchange traded funds based on
            the S&P 500, such as Standard & Poor's Depositary Receipt.

             Assets not invested in equity securities or derivatives may be
            invested in Fixed Income Instruments. The Portfolio may invest up
            to 10% of its assets in high yield securities ("junk bonds") rated
            B or higher by Moody's or S&P, or, if unrated, determined by PIMCO
            to be of comparable quality. The Portfolio may invest up to 20% of
            its assets in securities denominated in foreign currencies and may
            invest beyond this limit in U.S. dollar denominated securities of
            foreign issuers. The Portfolio will normally hedge at least 75% of
            its exposure to foreign currency to reduce the risk of loss due to
            fluctuations in currency exchange rates. In addition, the
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income.

- --------------------------------------------------------------------------------
Principal   Under certain conditions, generally in a market where the value of
Risks       both S&P 500 derivatives and fixed income securities are
            declining, the Portfolio may experience greater losses than would
            be the case if it invested directly in a portfolio of S&P 500
            stocks. Among the principal risks of investing in the Portfolio,
            which could adversely affect its net asset value, yield and total
            return, are:

              . Market Risk          . Interest Rate        . Mortgage Risk
              . Issuer Risk             Risk                . Leveraging Risk
              . Derivatives Risk     . Liquidity Risk       . Management Risk
              . Credit Risk          . Foreign
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.
                                     . Currency Risk

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.

9  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

                                            Highest and Lowest Quarter Returns
                                            (for periods shown in the bar chart)
                                            --------------------
   [GRAPH]                                  Highest (4th Qtr. '98)21.95%
                                            --------------------
'98     30.11%                              Lowest (3rd Qtr. '98)-8.82%
'99     19.85%

                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)
<TABLE>
<CAPTION>
                                                                                   Portfolio
                                                                                   Inception
                                              1 Year                               (12/31/97)
            ---------------------------------------------------------------------------------
         <S>                                  <C>                                  <C>
         Administrative Class                 19.85%                               24.87%
            ---------------------------------------------------------------------------------
         S&P 500 Index(1)                     21.04%                               24.75%
            ---------------------------------------------------------------------------------
</TABLE>

            (1) The Standard & Poor's 500 Composite Stock Price Index is an
                unmanaged index of common stocks. It is not possible to invest
                directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.40%    0.15%   0.10%(1) 0.65%               0.00%        0.65%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.10% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operation expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $208               $362               $810
            -----------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus  10
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

High        Portfolios that invest in high yield securities and unrated
Yield       securities of similar credit quality (commonly known as "junk
Risk        bonds") may be subject to greater levels of interest rate, credit
            and liquidity risk than Portfolios that do not invest in such
            securities. High yield securities are considered predominately
            speculative with respect to the issuer's continuing ability to
            make principal and interest payments. An economic downturn or
            period of rising interest rates could adversely affect the market
            for high yield securities and reduce a Portfolio's ability to sell
            its high yield securities (liquidity risk).

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

11 PIMCO Variable Insurance Trust
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolios may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    Portfolios that invest directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies are subject to the risk that those currencies
            will decline in value relative to the U.S. dollar, or, in the case
            of hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary

                                                                  Prospectus 12
<PAGE>

            Fund, or by the imposition of currency controls or other political
            developments in the U.S. or abroad. As a result, a Portfolio's
            investments in foreign currency-denominated securities may reduce
            the returns of a Portfolio.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

13 PIMCO Variable Insurance Trust
<PAGE>

                Management of the Portfolios

Investment      PIMCO serves as investment adviser and the administrator
Adviser         (serving in its capacity as administrator, the "Administrator")
and             for the Portfolios. Subject to the supervision of the Board of
Administrator   Trustees, PIMCO is responsible for managing the investment
                activities of the Portfolios and the Portfolios' business
                affairs and other administrative matters.

                 PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
                Beach, California 92660. Organized in 1971, PIMCO provides
                investment management and advisory services to private accounts
                of institutional and individual clients and to mutual funds. As
                of December 31, 1999, PIMCO had approximately $186 billion in
                assets under management.

Advisory        Each Portfolio pays PIMCO fees in return for providing
Fees            investment advisory services. For the fiscal year ended December
                31, 1999, the Portfolios paid monthly advisory fees to PIMCO at
                the following annual rates (stated as a percentage of the
                average daily net assets of each Portfolio taken separately):

                Portfolio                  Advisory Fees
                -----------------------------------------
                High Yield Bond Portfolio      0.50%
                All other Portfolios           0.40%

                 Effective April 1, 2000, the Portfolios pay monthly advisory
                fees to PIMCO at the following annual rates (stated as a
                percentage of the average daily net assets of each Portfolio
                taken separately):

                Portfolio                                 Advisory Fees
                ---------------------------------------------------------
                StocksPLUS Growth and Income Portfolio      0.40%
                All other Portfolios                        0.25%

Administrative  Each Portfolio pays for the administrative services it requires
Fees            under a fee structure which is essentially fixed. Shareholders
                of each Portfolio pay an administrative fee to PIMCO, computed
                as a percentage of the Portfolio's assets attributable in the
                aggregate to that class of shares. PIMCO, in turn, provides or
                procures administrative services for shareholders and also bears
                the costs of various third-party services required by the
                Portfolios, including audit, custodial, portfolio accounting,
                legal, transfer agency and printing costs. The result of this
                fee structure is an expense level for shareholders of each
                Portfolio that, with limited exceptions, is precise and
                predictable under ordinary circumstances.

                 For the fiscal year ended December 31, 1999, the Portfolios
                paid PIMCO monthly administrative fees at the following annual
                rates:

                Portfolio       Administrative Fees
                --------------------------------
                All Portfolios         0.25%

                 Effective April 1, 2000, the Portfolios pay PIMCO monthly
                administrative fees at the following annual rates:

                Portfolio                             Administrative Fees
                ------------------------------------------------------
                StocksPLUS Growth & Income Portfolio         0.10%
                High Yield Bond Portfolio                    0.35%
                Total Return Bond Portfolio                  0.25%

                                                                  Prospectus 14
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

                                                         Recent Professional
            Portfolio          Portfolio Manager  Since  Experience
            -------------------------------------------------------------------
            Total Return Bond  William H. Gross   12/97* Managing Director,
            StocksPLUS                                   Chief Investment
                                                         Officer and a founding
                                                         partner of PIMCO. He
                                                         leads a team which
                                                         manages the StocksPLUS
                                                         Portfolio.
              Growth and Income                   12/97*

            High Yield Bond    Benjamin L. Trosky  4/98* Managing Director,
                                                         PIMCO. He joined
                                                         PIMCO as a Portfolio
                                                         Manager in 1990.
            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

15 PIMCO Variable Insurance Trust
<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of each Portfolio. The Plan allows the
            Portfolios to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits a Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of a Portfolio's Administrative Class assets on
            an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account

                                                                  Prospectus 16
<PAGE>

            allocating assets to the Portfolios are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolios might be
            required to redeem the investment of one or more of its separate
            accounts from the Portfolios, which might force the Portfolios to
            sell securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolios to dispose of
            their securities or to determine fairly the value of their net
            assets, or during any other period as permitted by the SEC for the
            protection of investors. In the event that a Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Administrative Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.


17 PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus 18
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  Most of the Portfolios in this prospectus seek maximum total
Selection   return. The total return sought by a Portfolio consists of both
            income earned on a Portfolio's investments and capital
            appreciation, if any, arising from increases in the market value
            of a Portfolio's holdings. Capital appreciation of fixed income
            securities generally results from decreases in market interest
            rates or improving credit fundamentals for a particular market
            sector or security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of a Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio may invest all of its assets in mortgage- and
Related     asset-backed securities. Mortgage-related securities include
and Other   mortgage pass-through securities, collateralized mortgage
Asset-      obligations ("CMOs"), commercial mortgage-backed securities,
Backed      mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities  securities ("SMBSs") and other securities that directly or
            indirectly represent a participation in, or are secured by and
            payable from, mortgage loans on real property.

19 PIMCO Variable Insurance Trust
<PAGE>

                  The value of some mortgage- or asset-backed securities may be
                 particularly sensitive to changes in prevailing interest rates.
                 Early repayment of principal on some mortgage-related
                 securities may expose a Portfolio to a lower rate of return
                 upon reinvestment of principal. When interest rates rise, the
                 value of a mortgage-related security generally will decline;
                 however, when interest rates are declining, the value of
                 mortgage-related securities with prepayment features may not
                 increase as much as other fixed income securities. The rate of
                 prepayments on underlying mortgages will affect the price and
                 volatility of a mortgage-related security, and may shorten or
                 extend the effective maturity of the security beyond what was
                 anticipated at the time of purchase. If unanticipated rates of
                 prepayment on underlying mortgages increase the effective
                 maturity of a mortgage-related security, the volatility of the
                 security can be expected to increase. The value of these
                 securities may fluctuate in response to the market's perception
                 of the creditworthiness of the issuers. Additionally, although
                 mortgages and mortgage-related securities are generally
                 supported by some form of government or private guarantee
                 and/or insurance, there is no assurance that private guarantors
                 or insurers will meet their obligations.

                  One type of SMBS has one class receiving all of the interest
                 from the mortgage assets (the interest-only, or "IO" class),
                 while the other class will receive all of the principal (the
                 principal-only, or "PO" class). The yield to maturity on an IO
                 class is extremely sensitive to the rate of principal payments
                 (including prepayments) on the underlying mortgage assets, and
                 a rapid rate of principal payments may have a material adverse
                 effect on a Portfolio's yield to maturity from these
                 securities. A Portfolio may not invest more than 5% of its net
                 assets in any combination of IO, PO, or inverse floater
                 securities. The Portfolios may invest in other asset-backed
                 securities that have been offered to investors.

Loan             Certain Portfolios may invest in fixed- and floating-rate
Participations   loans, which investments generally will be in the form of loan
and              participations and assignments of portions of such loans.
Assignments      Participations and assignments involve special types of risk,
Assignments      includind credit risk, interest rate risk, liquidity risk, and
                 the risk of being a lender. If a Portfolio purchases a
                 participation, it may only be able to enforce its rights
                 through the lender, and may assume the credit risk of the
                 lender in addition to the borrower.

Corporate        Corporate debt securities are subject to the risk of the
Debt             issuer's inability to meet principal and interest payments on
Securities       the obligation and may also be subject to price volatility due
                 to such factors as interest rate sensitivity, market perception
                 of the credit-worthiness of the issuer and general market
                 liquidity. When interest rates rise, the value of corporate
                 debt securities can be expected to decline. Debt securities
                 with longer maturities tend to be more sensitive to interest
                 rate movements than those with shorter maturities.

High             Securities rated lower than Baa by Moody's Investors Service,
Yield            Inc. ("Moody's") or lower than BBB by Standard & Poor's
Securities       Ratings Services ("S&P") are sometimes referred to as "high
                 yield" or "junk" bonds. Investing in high yield securities
                 involves special risks in addition to the risks associated with
                 investments in higher-rated fixed income securities. While
                 offering a greater potential opportunity for capital
                 appreciation and higher yields, high yield securities typically
                 entail greater potential price volatility and may be less
                 liquid than higher-rated securities. High yield securities may
                 be regarded as predominately speculative with respect to the
                 issuer's continuing ability to meet principal and interest
                 payments. They may also be more susceptible to real or
                 perceived adverse economic and competitive industry conditions
                 than higher-rated securities.

                   . Credit Ratings and Unrated Securities. Rating agencies are
                 private services that provide ratings of the credit quality of
                 fixed income securities, including convertible securities.
                 Appendix A to this Offering Memorandum describes the various
                 ratings assigned to fixed income securities by Moody's and S&P.
                 Ratings assigned by a rating agency are not absolute standards
                 of credit quality and do not evaluate market risks. Rating
                 agencies may fail to make timely changes in credit ratings and
                 an issuer's current financial condition may be better or worse
                 than a rating indicates. A Portfolio will not necessarily sell
                 a security when its rating is reduced below its rating at the
                 time of purchase. PIMCO does not rely solely on credit ratings,
                 and develops its own analysis of issuer credit quality.

                                                                  Prospectus 20
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

            Variable and floating rate securities provide for a periodic
Variable    adjustment in the interest rate paid on the obligations. Each
and         Portfolio may invest in floating rate debt instruments
Floating    ("floaters") and engage in credit spread trades. While floaters
Rate        provide a certain degree of protection against rises in interest
Securities  rates, a Portfolio will participate in any declines in interest
            rates as well. Each Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. A Portfolio may not invest more than 5% of
            its assets in any combination of inverse floater, interest only,
            or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      Each Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

21 PIMCO Variable Insurance Trust
<PAGE>

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

            Investing in the securities of issuers in any foreign country
Foreign     involves special risks and considerations not typically associated
(Non-       with investing in U.S. companies. Shareholders should consider
U.S.)       carefully the substantial risks involved for Portfolios that
Securities  invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             Certain Portfolios also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. Each Portfolio that may invest in
            foreign securities, may invest up to 10% of its assets in
            securities of issuers based in countries with developing (or
            "emerging market") economies. Investing in emerging market
            securities imposes risks different from, or greater than, risks of
            investing in domestic securities or in foreign, developed
            countries. These risks include: smaller market capitalization of
            securities markets, which may suffer periods of relative
            illiquidity; significant price volatility; restrictions on foreign
            investment; possible repatriation of investment income and
            capital. In addition, foreign investors may be required to
            register the proceeds of sales; future economic or political
            crises could lead to price controls, forced mergers, expropriation
            or confiscatory taxation, seizure, nationalization, or creation of
            government monopolies. The currencies of emerging market countries
            may experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                Prospectus 22
<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             Each Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolios' assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolios.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into
            forward foreign currency exchange contracts and invest in foreign
            currency futures contracts and options on foreign currencies and
            futures. A forward foreign currency exchange contract, which
            involves an obligation to purchase or sell a specific currency at
            a future date at a price set at the time of the contract, reduces
            a Portfolio's exposure to changes in the value of the currency it
            will deliver and increases its exposure
            to changes in the value of the currency it will receive for the
            duration of the contract. The effect on the value of a Portfolio
            is similar to selling securities denominated in one currency and
            purchasing securities denominated in another currency. A contract
            to sell foreign currency would limit any potential gain which
            might be realized if the value of the hedged currency increases. A
            Portfolio may enter into these contracts to hedge against foreign
            exchange risk, to increase exposure to a foreign currency or to
            shift exposure to foreign currency fluctuations from one currency
            to another. Suitable hedging transactions may not be available in
            all circumstances and there can be no assurance that a Portfolio
            will engage in such transactions at any given time or from time to
            time. Also, such transactions may not be successful and may
            eliminate any chance for a Portfolio to benefit from favorable
            fluctuations in relevant foreign currencies. A Portfolio may use
            one currency (or a basket of currencies) to hedge against adverse
            changes in the value of another currency (or a basket of
            currencies) when exchange rates between the two currencies are
            positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations
            under forward foreign currency exchange contracts entered into for
            non-hedging purposes.

Repurchase  Each Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


23 PIMCO Variable Insurance Trust
<PAGE>

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. Each Portfolio may
            invest all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolios may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus 24
<PAGE>

             each Portfolio will segregate assets determined to be liquid by
             PIMCO in accordance with procedures established by the Board of
             Trustees (or, as permitted by applicable regulation, enter into
             certain offsetting positions) to cover its obligations under
             derivative instruments.

              Lack of Availability. Because the markets for certain derivative
             instruments (including markets located in foreign countries) are
             relatively new and still developing, suitable derivatives
             transactions may not be available in all circumstances for risk
             management or other purposes. There is no assurance that a
             Portfolio will engage in derivatives transactions at any time or
             from time to time. A Portfolio's ability to use derivatives may
             also be limited by certain regulatory and tax considerations.

              Market and Other Risks. Like most other investments, derivative
             instruments are subject to the risk that the market value of the
             instrument will change in a way detrimental to a Portfolio's
             interest. If a portfolio manager incorrectly forecasts the values
             of securities, currencies or interest rates or other economic
             factors in using derivatives for a Portfolio, the Portfolio might
             have been in a better position if it had not entered into the
             transaction at all. While some strategies involving derivative
             instruments can reduce the risk of loss, they can also reduce the
             opportunity for gain or even result in losses by offsetting
             favorable price movements in other Portfolio investments. A
             Portfolio may also have to buy or sell a security at a
             disadvantageous time or price because the Portfolio is legally
             required to maintain offsetting positions or asset coverage in
             connection with certain derivatives transactions.

              Other risks in using derivatives include the risk of mispricing
             or improper valuation of derivatives and the inability of
             derivatives to correlate perfectly with underlying assets, rates
             and indexes. Many derivatives, in particular privately negotiated
             derivatives, are complex and often valued subjectively. Improper
             valuations can result in increased cash payment requirements to
             counterparties or a loss of value to a Portfolio. Also, the value
             of derivatives may not correlate perfectly, or at all, with the
             value of the assets, reference rates or indexes they are designed
             to closely track. In addition, a Portfolio's use of derivatives
             may cause the Portfolio to realize higher amounts of short-term
             capital gains (generally taxed at ordinary income tax rates) than
             if the Portfolio had not used such instruments.

Delayed      The Portfolios may also enter into, or acquire participations in,
Funding      delayed funding loans and revolving credit facilities, in which a
Loans and    lender agrees to make loans up to a maximum amount upon demand by
Revolving    the borrower during a specified term. These commitments may have
Credit       the effect of requiring a Portfolio to increase its investment in
Facilities   a company at a time when it might not otherwise decide to do so
             (including at a time when the company's financial condition makes
             it unlikely that such amounts will be repaid). To the extent that
             a Portfolio is committed to advance additional funds, it will
             segregate assets determined to be liquid by PIMCO in accordance
             with procedures established by the Board of Trustees in an amount
             sufficient to meet such commitments. Delayed funding loans and
             revolving credit facilities are subject to credit, interest rate
             and liquidity risk and the risks of being a lender.

When-        Each Portfolio may purchase securities which it is eligible to
Issued,      purchase on a when-issued basis, may purchase and sell such
Delayed      securities for delayed delivery and may make contracts to purchase
Delivery     such securities for a fixed price at a future date beyond normal
and          settlement time (forward commitments). When-issued transactions,
Forward      delayed delivery purchases and forward commitments involve a risk
Commitment   of loss if the value of the securities declines prior to the
Transactions settlement date. This risk is in addition to the risk that the
             Portfolio's other assets will decline in the value. Therefore,
             these transactions may result in a form of leverage and increase a
             Portfolio's overall investment exposure. Typically, no income
             accrues on securities a Portfolio has committed to purchase prior
             to the time delivery of the securities is made, although a
             Portfolio may earn income on securities it has segregated to cover
             these positions.


25 PIMCO Variable Insurance Trust
<PAGE>

Investment  Each Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, a Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, each
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       Each Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    Each Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.


                                                                   Prospectus 26
<PAGE>

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

27 PIMCO Variable Insurance Trust
<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                  Prospectus 28
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Total Return
 Administrative Class
      12/31/1999            $10.09     $0.58        $(0.64)(a)    $(0.06)     $(0.58)     $ 0.00        $ 0.00         $0.00
      12/31/1998(c)          10.00      0.56          0.28 (a)      0.84       (0.56)       0.00         (0.19)         0.00
High Yield
 Administrative Class
      12/31/1999            $ 9.67     $0.77        $(0.49)(a)    $ 0.28      $(0.77)     $ 0.00        $ 0.00         $0.00
      12/31/1998(d)          10.00      0.51         (0.34)(a)      0.17       (0.50)       0.00          0.00          0.00
StocksPLUS Growth and Income
 Administrative Class
      12/31/1999            $12.58     $0.76        $ 1.65 (a)    $ 2.41      $(0.61)     $(0.82)       $ 0.00         $0.00
      12/31/1998(c)          10.00      0.30          2.68 (a)      2.98       (0.29)      (0.11)         0.00          0.00
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(c) Commenced operations on December 31, 1997.
(d) Commenced operations on April 30, 1998.

29 PIMCO Variable Insurance Trust
<PAGE>




<TABLE>
<CAPTION>
                                                                     Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of      Investment
 Return                    Value               End     Expenses to    Income to   Portfolio
   of          Total        End    Total    of Period    Average       Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets     Net Assets    Rate
- -------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>           <C>          <C>


  $0.00       $(0.58)     $ 9.45   (0.58)%   $  3,877     0.65% (b)      5.96%       102%
   0.00        (0.75)      10.09    8.61        3,259     0.65           5.55        139


  $0.00       $(0.77)     $ 9.18    3.01 %   $151,020     0.75%          8.25%        13%
   0.00        (0.50)       9.67    1.80       49,761     0.75           7.90*        13


  $0.00       $(1.43)     $13.56   19.85 %   $230,412     0.65%          5.69%        34%
   0.00        (0.40)      12.58   30.11       58,264     0.65           5.30         61
</TABLE>
- -------
*   Annualized.
(b) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.69% for the
    period ended December 31, 1999.

                                                                  Prospectus 30
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

A-1 PIMCO Variable Insurance Trust
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

                                                                  Prospectus A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

A-3 PIMCO Variable Insurance Trust

<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

                                                                  Prospectus A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-888-746-2688 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.


[LOGO OF PIMCO FUNDS]


PIMCO Funds

840 Newport Center Drive
Suite 300
Newport Beach, CA 92660


<PAGE>

PIMCO Funds Prospectus


PIMCO Variable Insurance Trust

April 1, 2000

Share Class

Adm Administrative

- --------------------------------------------------------------------------------
STOCK PORTFOLIOS
StocksPLUS Growth and Income Portfolio



   This cover is not part of the Prospectus
                                                           [LOGO OF PIMCO FUNDS]

<PAGE>

            Prospectus


PIMCO          This Prospectus describes the PIMCO StocksPLUS Growth and Income
Variable       Portfolio (the "Portfolio"), which is a separate investment
Insurance      portfolio offered by the PIMCO Variable Insurance Trust (the
Trust          "Trust"). The Portfolio provides access to the professional
               investment management services offered by Pacific Investment
April 1,       Management Company ("PIMCO"). The investments made by the
2000           Portfolio at any given time are not expected to be the same as
               those made by other mutual funds for which PIMCO acts as
Share          investment adviser, including mutual funds with investment
Class          objectives and strategies similar to those of the Portfolio.
Administrative Accordingly, the performance of the Portfolio can be expected to
               vary from that of the other mutual funds.

               This Prospectus explains what you should know about the Portfolio
               before you invest. Please read it carefully.

               Shares of the Portfolio currently are sold to segregated asset
               accounts ("Separate Accounts") of insurance companies that fund
               variable annuity contracts and variable life insurance policies
               ("Variable Contracts"). Assets in the Separate Account are
               invested in shares of the Portfolio in accordance with allocation
               instructions received from owners of the Variable Contracts
               ("Variable Contract Owners"). Variable Contract Owners do not
               deal directly with the Portfolio to purchase or redeem shares.
               The allocation rights of Variable Contract Owners are described
               in the accompanying Separate Account prospectus. Shares of the
               Portfolio also may be sold to qualified pension and retirement
               plans outside of the separate account context.

               This Prospectus should be read in conjunction with the prospectus
               of the Separate Account. Both prospectuses should be read
               carefully and retained for future reference.

               The Securities and Exchange Commission has not approved or
               disapproved these securities, or determined if this Prospectus is
               truthful or complete. Any representation to the contrary is a
               criminal offense.

1 PIMCO Variable Insurance Trust
<PAGE>

            Table of Contents

         Summary Information..............................................   3
         Portfolio Summary................................................   5
           StocksPLUS Growth and Income Portfolio.........................   5
         Summary of Principal Risks.......................................   7
         Management of the Portfolio......................................  10
         Investment Options...............................................  11
         Purchases and Redemptions........................................  12
         How Portfolio Shares are Priced..................................  13
         Tax Consequences.................................................  14
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  15
         Financial Highlights.............................................  24
         Appendix A--Description of Securities Ratings.................... A-1

                                                                  Prospectus 2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolio.
Other important characteristics are described in the Portfolio Summary on page
5. Following the table are certain key concepts which are used throughout the
Prospectus.

<TABLE>
<CAPTION>
                                                                                             Non-U.S.
                                                                                             Dollar
                                                                               Credit        Denominated
                                            Main Investments          Duration Quality(1)    Securities(2)
- ----------------------------------------------------------------------------------------------------------
 <C>           <C>                          <S>                       <C>      <C>           <C>
 Stock         StocksPLUS Growth and Income S&P 500 stock index       0-1 year B to Aaa; max   0-20%(3)
 Portfolio                                  derivatives backed by a            10% below Baa
                                            portfolio of short-term
                                            fixed-income securities
- ----------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  Each Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)
Fixed       Fixed Income Instruments, as used in this Prospectus includes:
Income
Instruments . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio
Descriptions,
Performance
and Fees
            The Portfolio provides a broad range of investment choices. The
            following summaries identify the Portfolio's investment objective,
            principal investments and strategies, principal risks, performance
            information and fees and expenses. A more detailed "Summary of
            Principal Risks" describing principal risks of investing in the
            Portfolio begins after the Portfolio Summary.

             It is possible to lose money on investments in the Portfolio.

             An investment in the Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.

                                                                  Prospectus 4
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              S&P 500 stock        B to Aaa; maximum
and                                  index derivatives    10% below Baa
Strategies                           backed by a
              Seeks total            portfolio of         Dividend
              return which           short-term fixed     Frequency
              exceeds that of        income securities    Declared and
              the S&P 500                                 distributed
                                                          quarterly

                                     Average Portfolio
                                     Duration
                                     0-1 year

            The Portfolio seeks to exceed the total return of the S&P 500 by
            investing under normal circumstances substantially all of its
            assets in S&P 500 derivatives, backed by a portfolio of Fixed
            Income Instruments. The Portfolio may invest in common stocks,
            options, futures, options on futures and swaps. The Portfolio uses
            S&P 500 derivatives in addition to or in place of S&P 500 stocks
            to attempt to equal or exceed the performance of the S&P 500. The
            value of S&P 500 derivatives closely track changes in the value of
            the index. However, S&P 500 derivatives may be purchased with a
            fraction of the assets that would be needed to purchase the equity
            securities directly, so that the remainder of the assets may be
            invested in Fixed Income Instruments. PIMCO actively manages the
            fixed income assets held by the Portfolio with a view toward
            enhancing the Portfolio's total return, subject to an overall
            portfolio duration which is normally not expected to exceed one
            year.

             The S&P 500 is composed of 500 selected common stocks that
            represent approximately two-thirds of the total market value of
            all U.S. common stocks. The Portfolio is neither sponsored by nor
            affiliated with S&P. The Portfolio seeks to remain invested in S&P
            500 derivatives or S&P 500 stocks even when the S&P 500 is
            declining.

             Though the Portfolio does not normally invest directly in S&P 500
            securities, when S&P 500 derivatives appear to be overvalued
            relative to the S&P 500, the Portfolio may invest all of its
            assets in a "basket" of S&P 500 stocks. Individual stocks are
            selected based on an analysis of the historical correlation
            between the return of every S&P 500 stock and the return on the
            S&P 500 itself. PIMCO may employ fundamental analysis of factors
            such as earnings and earnings growth, price to earnings ratio,
            dividend growth, and cash flows to choose among stocks that
            satisfy the correlation tests. Stocks chosen for the Portfolio are
            not limited to those with any particular weighting in the S&P 500.
            The Portfolio may also invest in exchange traded funds based on
            the S&P 500, such as Standard & Poor's Depositary Receipt.

             Assets not invested in equity securities or derivatives may be
            invested in Fixed Income Instruments. The Portfolio may invest up
            to 10% of its assets in high yield securities ("junk bonds") rated
            B or higher by Moody's or S&P, or, if unrated, determined by PIMCO
            to be of comparable quality. The Portfolio may invest up to 20% of
            its assets in securities denominated in foreign currencies and may
            invest beyond this limit in U.S. dollar denominated securities of
            foreign issuers. The Portfolio will normally hedge at least 75% of
            its exposure to foreign currency to reduce the risk of loss due to
            fluctuations in currency exchange rates. In addition, the
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income.

- --------------------------------------------------------------------------------
Principal   Under certain conditions, generally in a market where the value of
Risks       both S&P 500 derivatives and fixed income securities are
            declining, the Portfolio may experience greater losses than would
            be the case if it invested directly in a portfolio of S&P 500
            stocks. Among the principal risks of investing in the Portfolio,
            which could adversely affect its net asset value, yield and total
            return, are:

              . Market Risk          . Interest Rate        . Mortgage Risk
              . Issuer Risk             Risk                . Leveraging Risk
              . Derivatives Risk     . Liquidity Risk       . Management Risk
              . Credit Risk          . Foreign
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.
                                     . Currency Risk

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.

5  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class
<TABLE>
<S>                                                         <C>
                                                            Highest and Lowest Quarter Returns
                                                            (for periods shown in the bar chart)
                                                            --------------------
                               [GRAPH]                      Highest (4th Qtr. '98)21.95%
                                                            --------------------
                            1998      30.11%                Lowest (3rd Qtr. '98)-8.82%
                            1999      19.85%
</TABLE>
                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)
<TABLE>
<CAPTION>
                                                                                   Portfolio
                                                                                   Inception
                                              1 Year                               (12/31/97)
            ---------------------------------------------------------------------------------
         <S>                                  <C>                                  <C>
         Administrative Class                 19.85%                               24.87%
            ---------------------------------------------------------------------------------
         S&P 500 Index(1)                     21.04%                               24.75%
            ---------------------------------------------------------------------------------
</TABLE>

            (1) The Standard & Poor's 500 Composite Stock Price Index is an
                unmanaged index of common stocks. It is not possible to invest
                directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.40%    0.15%   0.10%(1) 0.65%               0.00%        0.65%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.10% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operation expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $208               $362               $810
            -----------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on the Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of the Portfolio are
            identified in the Portfolio Summary and are described in this
            section. The Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by the Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, its investments and the related risks. There is no
            guarantee that the Portfolio will be able to achieve its
            investment objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

7 PIMCO Variable Insurance Trust
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolio may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolio typically uses derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolio may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    Portfolios that invest directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies are subject to the risk that those currencies
            will decline in value relative to the U.S. dollar, or, in the case
            of hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary

                                                                  Prospectus 8
<PAGE>

            Fund, or by the imposition of currency controls or other political
            developments in the U.S. or abroad. As a result, a Portfolio's
            investments in foreign currency-denominated securities may reduce
            the returns of a Portfolio.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

9 PIMCO Variable Insurance Trust
<PAGE>

            Management of the Portfolio

Investment      PIMCO serves as investment adviser and the administrator
Adviser         (serving in its capacity as administrator, the "Administrator")
and             for the Portfolio. Subject to the supervision of the Board of
Administrator   Trustees, PIMCO is responsible for managing the investment
                activities of the Portfolio and the Portfolio's business affairs
                and other administrative matters.

                 PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
                Beach, California 92660. Organized in 1971, PIMCO provides
                investment management and advisory services to private accounts
                of institutional and individual clients and to mutual funds. As
                of December 31, 1999, PIMCO had approximately $186 billion in
                assets under management.

Advisory        The Portfolio pays PIMCO fees in return for providing investment
Fees            advisory services. For the fiscal year ended December 31, 1999,
                the Portfolio paid monthly advisory fees to PIMCO at the
                following annual rates (stated as a percentage of the average
                daily net assets of the Portfolio taken separately):

                Portfolio                                         Advisory Fees
                ----------------------------------------------------------------
                StocksPLUS Growth and Income Portfolio               0.40%

                 Effective April 1, 2000, the Portfolio pays monthly advisory
                fees to PIMCO at the following annual rates (stated as a
                percentage of the average daily net assets of the Portfolio
                taken separately):

                Portfolio                                         Advisory Fees
                ----------------------------------------------------------------
                StocksPLUS Growth and Income Portfolio                0.40%

Administrative  The Portfolio pays for the administrative services it requires
Fees            under a fee structure which is essentially fixed. Shareholders
                of the Portfolio pay an administrative fee to PIMCO, computed as
                a percentage of the Portfolio's assets attributable in the
                aggregate to that class of shares. PIMCO, in turn, provides or
                procures administrative services for shareholders and also bears
                the costs of various third-party services required by the
                Portfolio, including audit, custodial, portfolio accounting,
                legal, transfer agency and printing costs. The result of this
                fee structure is an expense level for shareholders of the
                Portfolio that, with limited exceptions, is precise and
                predictable under ordinary circumstances.

                 For the fiscal year ended December 31, 1999, the Portfolio paid
                PIMCO monthly administrative fees at the following annual rates:

                Portfolio                                   Administrative Fees
                ----------------------------------------------------------------
                StocksPLUS Growth and Income Portfolio            0.25%

                 Effective April 1, 2000, the Portfolio pays PIMCO monthly
                administrative fees at the following annual rates:

                Portfolio                                   Administrative Fees
                ----------------------------------------------------------------
                StocksPLUS Growth & Income Portfolio               0.10%

                                                                  Prospectus 10
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by the Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolio, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio manager responsible for management of the Trust's
Managers    Portfolio, including their occupation for the past five years.

                               Portfolio                Recent Professional
            Portfolio          Manager          Since   Experience
            -------------------------------------------------------------------
            StocksPLUS         William H. Gross 12/97*  Managing Director, Chief
            Growth and Income                   12/97*  Investment Officer and a
                                                        founding partner of
                                                        PIMCO. He leads a team
                                                        which manages the
                                                        StocksPLUS Portfolio.
            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolio. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

11 PIMCO Variable Insurance Trust
<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of the Portfolio. The Plan allows the
            Portfolio to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits the Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of the Portfolio's Administrative Class assets
            on an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolio may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolio to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolio.

             As of the date of this Prospectus, shares of the Portfolio are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolio currently does not foresee any disadvantages
            to Variable Contract Owners if the Portfolio serves as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolio served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            the insurance company with a separate account

                                                                  Prospectus 12
<PAGE>

            allocating assets to the Portfolio are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolio might be required
            to redeem the investment of one or more of its separate accounts
            from the Portfolio, which might force the Portfolio to sell
            securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolio or to reject any purchase order, in whole or in part, or
            to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolio to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the SEC for the
            protection of investors. In the event that the Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolio to dispose of its
            securities or to determine fairly the value of its net assets, or
            during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by the Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of the Portfolio's Administrative
            Class shares is determined by dividing the total value of the
            Portfolio's investments and other assets attributable to that
            class, less any liabilities, by the total number of shares
            outstanding of that class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.

13 PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of the Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolio normally uses pricing data for
            domestic equity securities received shortly after the NYSE Close
            and does not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolio or its
            agents after the NAV has been calculated on a particular day will
            not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolio may value securities at fair value or
            estimate its value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

            Tax Consequences

            The Portfolio intends to qualify as a regulated investment company
            annually and to elect to be treated as a regulated investment
            company for federal income tax purposes. As such, the Portfolio
            generally will not pay federal income tax on the income and gains
            it pays as dividends to its shareholders. In order to avoid a 4%
            federal excise tax, the Portfolio intends to distribute each year
            substantially all of its net income and gains.

             The Portfolio also intends to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolio's Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus 14
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolio described
            under the "Portfolio Summary" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolio from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolio. As with any mutual fund, investors in
            the Portfolio rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolio.

Securities  The Portfolio seeks maximum total return. The total return sought
Selection   by the Portfolio consists of both income earned on the Portfolio's
            investments and capital appreciation, if any, arising from
            increases in the market value of the Portfolio's holdings. Capital
            appreciation of fixed income securities generally results from
            decreases in market interest rates or improving credit
            fundamentals for a particular market sector or security.

             In selecting securities for the Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of the Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolio may invest include municipal lease obligations. The
            Portfolio may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   The Portfolio may invest all of its assets in mortgage- and asset-
Related     backed securities. Mortgage-related securities include mortgage
and Other   pass-through securities, collateralized mortgage obligations
Asset-      ("CMOs"), commercial mortgage-backed securities, mortgage dollar
Backed      rolls, CMO residuals, stripped mortgage-backed securities
Securities  ("SMBSs") and other securities that directly or indirectly
            represent a participation in, or are secured by and payable from,
            mortgage loans on real property.

15 PIMCO Variable Insurance Trust
<PAGE>

                The value of some mortgage- or asset-backed securities may be
               particularly sensitive to changes in prevailing interest rates.
               Early repayment of principal on some mortgage-related securities
               may expose a Portfolio to a lower rate of return upon
               reinvestment of principal. When interest rates rise, the value of
               a mortgage-related security generally will decline; however, when
               interest rates are declining, the value of mortgage-related
               securities with prepayment features may not increase as much as
               other fixed income securities. The rate of prepayments on
               underlying mortgages will affect the price and volatility of a
               mortgage-related security, and may shorten or extend the
               effective maturity of the security beyond what was anticipated at
               the time of purchase. If unanticipated rates of prepayment on
               underlying mortgages increase the effective maturity of a
               mortgage-related security, the volatility of the security can be
               expected to increase. The value of these securities may fluctuate
               in response to the market's perception of the creditworthiness of
               the issuers. Additionally, although mortgages and mortgage-
               related securities are generally supported by some form of
               government or private guarantee and/or insurance, there is no
               assurance that private guarantors or insurers will meet their
               obligations.

                One type of SMBS has one class receiving all of the interest
               from the mortgage assets (the interest-only, or "IO" class),
               while the other class will receive all of the principal (the
               principal-only, or "PO" class). The yield to maturity on an IO
               class is extremely sensitive to the rate of principal payments
               (including prepayments) on the underlying mortgage assets, and a
               rapid rate of principal payments may have a material adverse
               effect on a Portfolio's yield to maturity from these securities.
               A Portfolio may not invest more than 5% of its net assets in any
               combination of IO, PO, or inverse floater securities. The
               Portfolio may invest in other asset-backed securities that have
               been offered to investors.

Loan           The Portfolio may invest in fixed- and floating-rate loans, which
Participations investments generally will be in the form of loan participations
and            and assignments of portions of such loans. Participations and
Assignments    assignments involve special types of risk, including credit risk,
               interest rate risk, liquidity risk, and the risks of being a
               lender. If a Portfolio purchases a participation, it may only be
               able to enforce its rights through the lender, and may assume the
               credit risk of the lender in addition to the borrower.

Corporate      Corporate debt securities are subject to the risk of the issuer's
Debt           inability to meet principal and interest payments on the
Securities     obligation and may also be subject to price volatility due to
               such factors as interest rate sensitivity, market perception of
               the credit-worthiness of the issuer and general market liquidity.
               When interest rates rise, the value of corporate debt securities
               can be expected to decline. Debt securities with longer
               maturities tend to be more sensitive to interest rate movements
               than those with shorter maturities.

High           Securities rated lower than Baa by Moody's Investors Service,
Yield          Inc. ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities     Services ("S&P") are sometimes referred to as "high yield" or
               "junk" bonds. Investing in high yield securities involves special
               risks in addition to the risks associated with investments in
               higher-rated fixed income securities. While offering a greater
               potential opportunity for capital appreciation and higher yields,
               high yield securities typically entail greater potential price
               volatility and may be less liquid than higher-rated securities.
               High yield securities may be regarded as predominately
               speculative with respect to the issuer's continuing ability to
               meet principal and interest payments. They may also be more
               susceptible to real or perceived adverse economic and competitive
               industry conditions than higher-rated securities.

               . Credit Ratings and Unrated Securities. Rating agencies are
               private services that provide ratings of the credit quality of
               fixed income securities, including convertible securities.
               Appendix A to this Offering Memorandum describes the various
               ratings assigned to fixed income securities by Moody's and S&P.
               Ratings assigned by a rating agency are not absolute standards of
               credit quality and do not evaluate market risks. Rating agencies
               may fail to make timely changes in credit ratings and an issuer's
               current financial condition may be better or worse than a rating
               indicates. A Portfolio will not necessarily sell a security when
               its rating is reduced below its rating at the time of purchase.
               PIMCO does not rely solely on credit ratings, and develops its
               own analysis of issuer credit quality.

                                                                  Prospectus 16
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

            Variable and floating rate securities provide for a periodic
Variable    adjustment in the interest rate paid on the obligations. The
and         Portfolio may invest in floating rate debt instruments
Floating    ("floaters") and engage in credit spread trades. While floaters
Rate        provide a certain degree of protection against rises in interest
Securities  rates, a Portfolio will participate in any declines in interest
            rates as well. The Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. The Portfolio may not invest more than 5%
            of its assets in any combination of inverse floater, interest
            only, or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      The Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, the Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible The Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

17 PIMCO Variable Insurance Trust
<PAGE>

             The Portfolio may invest in convertible securities or equity
            securities. While some countries or companies may be regarded as
            favorable investments, pure fixed income opportunities may be
            unattractive or limited due to insufficient supply, or legal or
            technical restrictions. In such cases, a Portfolio may consider
            convertible securities or equity securities to gain exposure to
            such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

            Investing in the securities of issuers in any foreign country
Foreign     involves special risks and considerations not typically associated
(Non-       with investing in U.S. companies. Shareholders should consider
U.S.)       carefully the substantial risks involved for Portfolios that
Securities  invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             The Portfolio also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. Portfolios that may invest in
            foreign securities may invest up to 10% of their assets in
            securities of issuers based in countries with developing (or
            "emerging market") economies. Investing in emerging market
            securities imposes risks different from, or greater than, risks of
            investing in domestic securities or in foreign, developed
            countries. These risks include: smaller market capitalization of
            securities markets, which may suffer periods of relative
            illiquidity; significant price volatility; restrictions on foreign
            investment; possible repatriation of investment income and
            capital. In addition, foreign investors may be required to
            register the proceeds of sales; future economic or political
            crises could lead to price controls, forced mergers, expropriation
            or confiscatory taxation, seizure, nationalization, or creation of
            government monopolies. The currencies of emerging market countries
            may experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                  Prospectus 18
<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             The Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolio's assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolio.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into forward
            foreign currency exchange contracts and invest in foreign currency
            futures contracts and options on foreign currencies and futures. A
            forward foreign currency exchange contract, which involves an
            obligation to purchase or sell a specific currency at a future date
            at a price set at the time of the contract, reduces a Portfolio's
            exposure to changes in the value of the currency it will deliver and
            increases its exposure to changes in the value of the currency it
            will receive for the duration of the contract. The effect on the
            value of a Portfolio is similar to selling securities denominated in
            one currency and purchasing securities denominated in another
            currency. A contract to sell foreign currency would limit any
            potential gain which might be realized if the value of the hedged
            currency increases. A Portfolio may enter into these contracts to
            hedge against foreign exchange risk, to increase exposure to a
            foreign currency or to shift exposure to foreign currency
            fluctuations from one currency to another. Suitable hedging
            transactions may not be available in all circumstances and there can
            be no assurance that a Portfolio will engage in such transactions at
            any given time or from time to time. Also, such transactions may not
            be successful and may eliminate any chance for a Portfolio to
            benefit from favorable fluctuations in relevant foreign currencies.
            A Portfolio may use one currency (or a basket of currencies) to
            hedge against adverse changes in the value of another currency (or a
            basket of currencies) when exchange rates between the two currencies
            are positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations under
            forward foreign currency exchange contracts entered into for non-
            hedging purposes.

Repurchase  The Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


19 PIMCO Variable Insurance Trust
<PAGE>

Reverse     The Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             The Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, the Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. The Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives The Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. The Portfolio may invest
            all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolio may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolio.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus 20
<PAGE>

            a Portfolio will segregate assets determined to be liquid by PIMCO
            in accordance with procedures established by the Board of Trustees
            (or, as permitted by applicable regulation, enter into certain
            offsetting positions) to cover its obligations under derivative
            instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolio may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring the Portfolio to increase its investment
Facilities  in a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            the Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       The Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Transac-    settlement date. This risk is in addition to the risk that the
tions       Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase
            the Portfolio's overall investment exposure. Typically, no income
            accrues on securities the Portfolio has committed to purchase
            prior to the time delivery of the securities is made, although the
            Portfolio may earn income on securities it has segregated to cover
            these positions.


21 PIMCO Variable Insurance Trust
<PAGE>

Investment  The Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, the Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, the
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       The Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    The Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, the Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." The Portfolio may engage in frequent and active trading
            of portfolio securities to achieve its investment objective,
            particularly during periods of volatile market movements. High
            portfolio turnover (e.g., over 100%) involves correspondingly
            greater expenses to a Portfolio, including brokerage commissions
            or dealer mark-ups and other transaction costs on the sale of
            securities and reinvestments in other securities. Such sales may
            also result in realization of taxable capital gains, including
            short-term capital gains (which are generally taxed at ordinary
            income tax rates). The trading costs and tax effects associated
            with portfolio turnover may adversely effect the Portfolio's
            performance.


                                                                   Prospectus 22
<PAGE>

Temporary   For temporary or defensive purposes, the Portfolio may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of the Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolio may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolio may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolio to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolio.

23 PIMCO Variable Insurance Trust
<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                   Prospectus 24
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
StocksPLUS Growth and Income
 Administrative Class
 12/31/1999            $12.58     $0.76        $1.65 (a)     $2.41       $(0.61)     $(0.82)        $0.00         $0.00
 12/31/1998(b)          10.00      0.30         2.68 (a)      2.98        (0.29)      (0.11)         0.00          0.00
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(b) Commenced operations on December 31, 1997.

25 PIMCO Variable Insurance Trust
<PAGE>




<TABLE>
<CAPTION>
                                                                   Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of    Investment
 Return                    Value               End     Expenses to  Income to   Portfolio
   of          Total        End    Total    of Period    Average     Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets   Net Assets    Rate
- -----------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>         <C>          <C>


  $0.00       $(1.43)     $13.56   19.85 %   $230,412     0.65%        5.69%        34%
   0.00        (0.40)      12.58   30.11       58,264     0.65         5.30         61
</TABLE>
- -------
*   Annualized.

                                                                  Prospectus 26
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

A-1 PIMCO Variable Insurance Trust
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings
& Poor's
Ratings     Investment Grade
Services
             AAA: Debt rated AAA has the highest rating assigned by Standard &
            Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

                                                                  Prospectus A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

A-3 PIMCO Variable Insurance Trust
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

                                                                  Prospectus A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------

<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.


[LOGO OF PIMCO FUNDS]


PIMCO Funds

840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

<PAGE>

PIMCO Funds Prospectus


PIMCO Variable Insurance Trust

April 1, 2000

Share Class

Adm Administrative

- --------------------------------------------------------------------------------
LONG DURATION BOND PORTFOLIO
Long-Term U.S. Government Bond Portfolio

- --------------------------------------------------------------------------------


   This cover is not part of the Prospectus


<PAGE>

            Prospectus


PIMCO           This Prospectus describes the PIMCO Long-Term U.S. Government
Variable        Portfolio (the "Portfolio"), which is a separate investment
Insurance       portfolio, offered by the PIMCO Variable Insurance Trust (the
Trust           "Trust"). The Portfolio provides access to the professional
                investment management services offered by Pacific Investment
April 1,        Management Company ("PIMCO"). The investments made by the
2000            Portfolio at any given time are not expected to be the same as
                those made by other mutual funds for which PIMCO acts as
Share           investment adviser, including mutual funds with investment
Class           objectives and strategies similar to those of the Portfolio.
Administrative  Accordingly, the performance of the Portfolio can be expected to
                vary from that of the other mutual funds.

                This Prospectus explains what you should know about the
                Portfolio before you invest. Please read it carefully.

                Shares of the Portfolio currently are sold to segregated asset
                accounts ("Separate Accounts") of insurance companies that fund
                variable annuity contracts and variable life insurance policies
                ("Variable Contracts"). Assets in the Separate Account are
                invested in shares of the Portfolio in accordance with
                allocation instructions received from owners of the Variable
                Contracts ("Variable Contract Owners"). Variable Contract Owners
                do not deal directly with the Portfolio to purchase or redeem
                shares. The allocation rights of Variable Contract Owners are
                described in the accompanying Separate Account prospectus.
                Shares of the Portfolio also may be sold to qualified pension
                and retirement plans outside of the separate account context.

                This Prospectus should be read in conjunction with the
                prospectus of the Separate Account. Both prospectuses should be
                read carefully and retained for future reference.

                The Securities and Exchange Commission has not approved or
                disapproved these securities, or determined if this Prospectus
                is truthful or complete. Any representation to the contrary is a
                criminal offense.

1 PIMCO Variable Insurance Trust
<PAGE>

            Table of Contents

         Summary Information..............................................   3
         Portfolio Summary................................................   5
           Long-Term U.S. Government Portfolio............................   5
         Summary of Principal Risks.......................................   7
         Management of the Portfolio......................................   9
         Investment Options...............................................  10
         Purchases and Redemptions........................................  11
         How Portfolio Shares are Priced..................................  12
         Tax Consequences.................................................  13
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  13
         Financial Highlights.............................................  23
         Appendix A--Description of Securities Ratings.................... A-1

                                                                  Prospectus 2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolio.
Other important characteristics are described in the Portfolio Summary
beginning on page 5. Following the table are certain key concepts which are
used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                                 Non-U.S.
                                                                                                 Dollar
                                                                                      Credit     Denominated
                               Main Investments           Duration                    Quality(1) Securities
- ------------------------------------------------------------------------------------------------------------
 <C>           <C>             <S>                        <C>                         <C>        <C>
 Long          Long-Term       Long-term maturity fixed   (greater than or =) 8 years  A to Aaa      0%
 Duration      U.S. Government income securities
 Bond
 Portfolio
- ------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.

3  PIMCO Variable Insurance Trust
<PAGE>

                Summary Information (continued)
Fixed           The Long-Term U.S. Government Bond Portfolio is a "Fixed Income
Income          Portfolio." A Fixed Income Portfolio invests at least 65% of its
Instruments     assets in "Fixed Income Instruments," which as used in this
                Prospectus includes:

                . securities issued or guaranteed by the U.S. Government, its
                  agencies or government-sponsored enterprises ("U.S. Government
                  Securities");
                . corporate debt securities of U.S. and non-U.S. issuers,
                  including convertible securities and corporate commercial
                  paper;
                . mortgage-backed and other asset-backed securities;
                . inflation-indexed bonds issued both by governments and
                  corporations;
                . structured notes, including hybrid or "indexed" securities,
                  event-linked bonds and loan participations;
                . delayed funding loans and revolving credit facilities;
                . bank certificates of deposit, fixed time deposits and bankers'
                  acceptances;
                . repurchase agreements and reverse repurchase agreements;
                . debt securities issued by states or local governments and
                  their agencies, authorities and other instrumentalities;
                . obligations of non-U.S. governments or their subdivisions,
                  agencies and instrumentalities; and
                . obligations of international agencies or supranational
                  entities.

Duration        Duration is a measure of the expected life of a fixed income
                security that is used to determine the sensitivity of a
                security's price to changes in interest rates. The longer a
                security's duration, the more sensitive it will be to changes in
                interest rates. Similarly, a Portfolio with a longer average
                portfolio duration will be more sensitive to changes in interest
                rates than a Portfolio with a shorter average portfolio
                duration.

Credit          In this Prospectus, references are made to credit ratings of
Ratings         debt securities which measure an issuer's expected ability to
                pay principal and interest on time. Credit ratings are
                determined by rating organizations, such as Standard & Poor's
                Rating Service ("S&P") or Moody's Investors Service, Inc.
                ("Moody's"). The following terms are generally used to describe
                the credit quality of debt securities depending on the
                security's credit rating or, if unrated, credit quality as
                determined by PIMCO:

                . high quality
                . investment grade
                . below investment grade ("high yield securities" or "junk
                  bonds")

                 For a further description of credit ratings, see "Appendix A--
                Description of Securities Ratings."

Portfolio       The Portfolio provides a broad range of investment choices. The
Descriptions,   following summaries identify the Portfolio's investment
Performance     objective, principal investments and strategies, principal
and Fees        risks, performance information and fees and expenses. A more
                detailed "Summary of Principal Risks" describing principal
                risks of investing in the Portfolio begins after the Portfolio
                Summary.

                It is possible to lose money on investments in the Portfolio.

                 An investment in the Portfolio is not a deposit of a bank and
                is not guaranteed or insured by the Federal Deposit Insurance
                Corporation or any other government agency.

                                                                    Prospectus 4
<PAGE>

            PIMCO Long-Term U.S. Government Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Long-term            A to Aaa
and           Seeks maximum          maturity
Strategies    total return,          fixed income         Dividend Frequency
              consistent with        securities           Declared daily and
              preservation of                             distributed monthly
              capital and            Average Portfolio
              prudent                Duration
              investment             (greater than or
              management             =) 8 years

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of fixed income securities that are issued
            or guaranteed by the U.S. Government, its agencies or government-
            sponsored enterprises ("U.S. Government Securities"). Assets not
            invested in U.S. Government Securities may be invested in other
            types of Fixed Income Instruments. The Portfolio also may obtain
            exposure to U.S. Government Securities through the use of futures
            contracts (including related options) with respect to such
            securities, and options on such securities, when PIMCO deems it
            appropriate to do so. While PIMCO may invest in derivatives at any
            time it deems appropriate, it will generally do so when it
            believes that U.S. Government Securities are overvalued relative
            to derivative instruments. This Portfolio will normally have a
            minimum average portfolio duration of eight years. For point of
            reference, the dollar-weighted average portfolio maturity of the
            Portfolio is normally expected to be more than ten years.

             The Portfolio's investments in Fixed Income Instruments are
            limited to those of investment grade U.S. dollar-denominated
            securities of U.S. issuers that are rated at least A by Moody's or
            S&P, or, if unrated, determined by PIMCO to be of comparable
            quality. In addition, the Portfolio may only invest up to 10% of
            its assets in securities rated A by Moody's or S&P, and may only
            invest up to 25% of its assets in securities rated Aa by Moody's
            or AA by S&P.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage-backed securities. The Portfolio may
            lend its portfolio securities to brokers, dealers and other
            financial institutions to earn income. The Portfolio may seek to
            obtain market exposure to the securities in which it primarily
            invests by entering into a series of purchase and sale contracts
            or by using other investment techniques (such as buy backs or
            dollar rolls). The "total return" sought by the Portfolio consists
            of income earned on the Portfolio's investments, plus capital
            appreciation, if any, which generally arises from decreases in
            interest rates or improving credit fundamentals for a particular
            sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Issuer Risk         .  Leveraging Risk
                 Risk                .  Derivatives Risk    .  Management Risk
              .  Credit Risk         .  Mortgage Risk
              .  Market Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summary for a description of these and other risks of investing in
            the Portfolio.

- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.


5  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Long-Term U.S. Government Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)_____None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                      Total Annual                     Net Portfolio
                            Advisory Service Other    Portfolio Operating Expense      Operating
            Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------------
            <S>             <C>      <C>     <C>      <C>                 <C>          <C>
            Administrative  0.25%    0.15%   0.31%(1) 0.71%               (0.06%)          0.65%
            -------------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.06%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
            Share Class                         Year 1                                         Year 3
            --------------------------------------------------------------------------------------
            <S>                                 <C>                                            <C>
            Administrative                      $66                                            $221
            --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>


            Summary of Principal Risks

            The value of your investment in the Portfolio changes with the
            values of the Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on the Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of the Portfolio are
            identified in the Portfolio Summary and are described in this
            section. The Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by the Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, its investments and the related risks. There is no
            guarantee that the Portfolio will be able to achieve its
            investment objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

7 PIMCO Variable Insurance Trust
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolio may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolio typically uses derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolio may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  The Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and the portfolio
            manager will apply investment techniques and risk analyses in
            making investment decisions for the Portfolio, but there can be no
            guarantee that these will produce the desired results.

                                                                  Prospectus 8
<PAGE>

                Management of the Portfolio

Investment      PIMCO serves as investment adviser and the administrator
Adviser         (serving in its capacity as administrator, the "Administrator")
and             for the Portfolio. Subject to the supervision of the Board of
Administrator   Trustees, PIMCO is responsible for managing the investment
                activities of the Portfolio and the Portfolio's business affairs
                and other administrative matters.

                 PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
                Beach, California 92660. Organized in 1971, PIMCO provides
                investment management and advisory services to private accounts
                of institutional and individual clients and to mutual funds. As
                of December 31, 1999, PIMCO had approximately $186 billion in
                assets under management.

Advisory        The Portfolio pays PIMCO fees in return for providing investment
Fees            advisory services. For the fiscal year ended December 31, 1999,
                the Portfolio paid monthly advisory fees to PIMCO at the
                following annual rates (stated as a percentage of the average
                daily net assets of the Portfolio taken separately):

                Portfolio                                 Advisory Fees
                ---------------------------------------------------------
                Long-Term U.S. Government Bond Portfolio      0.40%

                 Effective April 1, 2000, the Portfolio pays monthly advisory
                fees to PIMCO at the following annual rates (stated as a
                percentage of the average daily net assets of the Portfolio
                taken separately):

                Portfolio                            Advisory Fees
                ----------------------------------------------------
                Long-Term U.S. Government Bond Portfolio      0.25%

Administrative  The Portfolio pays for the administrative services it requires
Fees            under a fee structure which is essentially fixed. Shareholders
                of the Portfolio pay an administrative fee to PIMCO, computed as
                a percentage of the Portfolio's assets attributable in the
                aggregate to that class of shares. PIMCO, in turn, provides or
                procures administrative services for shareholders and also bears
                the costs of various third-party services required by the
                Portfolio, including audit, custodial, portfolio accounting,
                legal, transfer agency and printing costs. The result of this
                fee structure is an expense level for shareholders of the
                Portfolio that, with limited exceptions, is precise and
                predictable under ordinary circumstances.

                 For the fiscal year ended December 31, 1999, the Portfolio paid
                PIMCO monthly administrative fees at the following annual rates:

                Portfolio                                 Administrative Fees
                ---------------------------------------------------------------
                Long-Term U.S. Government Bond Portfolio         0.25%

                 Effective April 1, 2000, the Portfolio pays PIMCO monthly
                administrative fees at the following annual rates:

                Portfolio                                 Administrative Fees
                ---------------------------------------------------------------
                Long-Term U.S. Government Bond Portfolio         0.25%

                 PIMCO may use its assets and resources, including its profits
                from advisory or administrative fees paid by the Portfolio, to
                pay insurance companies for services rendered to current and
                prospective owners of Variable Contracts, including the
                provision of support services such as providing information
                about the Trust and the Portfolio, the delivery of Trust
                documents, and other services. Any such payments are made by
                PIMCO and not by the Trust and PIMCO does not receive any
                separate fees for such expenses.

9 PIMCO Variable Insurance Trust
<PAGE>

Individual  The table below provides information about the individual
Portfolio   portfolio manager responsible for management of the Trust's
Manager     Portfolio, including his occupation for the past five years.

<TABLE>
<CAPTION>
                                           Portfolio             Recent Professional
            Portfolio                      Manager         Since Experience
            -----------------------------------------------------------------------
            <C>                            <C>             <C>   <S>
            Long-Term U.S. Government Bond James M. Keller 4/00  Executive Vice
                                                                 President, PIMCO. He
                                                                 joined PIMCO as a
                                                                 Portfolio Manager in
                                                                 1996, and has managed
                                                                 fixed income accounts
                                                                 for various
                                                                 institutional clients
                                                                 since that time.
</TABLE>

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolio. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of the Portfolio. The Plan allows the
            Portfolio to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits the Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of the Portfolio's Administrative Class assets
            on an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolio may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and

                                                                  Prospectus 10
<PAGE>

            would increase the cost of the customer's investment and lower
            investment returns. Each service agent is responsible for
            transmitting to its customers a schedule of any such fees and
            information regarding any additional or different conditions
            regarding purchases, redemptions and exchanges. Shareholders who
            are customers of service agents should consult their service
            agents for information regarding these fees and conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolio to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolio.

             As of the date of this Prospectus, shares of the Portfolio are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolio currently does not foresee any disadvantages
            to Variable Contract Owners if the Portfolio serves as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolio served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            the insurance company with a separate account allocating assets to
            the Portfolio are required to monitor events to identify any
            material conflicts between variable annuity contract owners and
            variable life insurance policy owners, and would have to determine
            what action, if any, should be taken in the event of such a
            conflict. If such a conflict occurred, an insurance company
            participating in the Portfolio might be required to redeem the
            investment of one or more of its separate accounts from the
            Portfolio, which might force the Portfolio to sell securities at
            disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolio or to reject any purchase order, in whole or in part, or
            to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolio to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the SEC for the
            protection of investors. In the event that the Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolio to dispose of its
            securities or to determine fairly the value of its net assets, or
            during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by the Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

11 PIMCO Variable Insurance Trust
<PAGE>

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of the Portfolio's Administrative
            Class shares is determined by dividing the total value of the
            Portfolio's investments and other assets attributable to that
            class, less any liabilities, by the total number of shares
            outstanding of that class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of the Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolio normally uses pricing data for
            domestic equity securities received shortly after the NYSE Close
            and does not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolio or its
            agents after the NAV has been calculated on a particular day will
            not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolio may value securities at fair value or
            estimate its value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.


                                                                  Prospectus 12
<PAGE>

            Tax Consequences

            The Portfolio intends to qualify as a regulated investment company
            annually and to elect to be treated as a regulated investment
            company for federal income tax purposes. As such, the Portfolio
            generally will not pay federal income tax on the income and gains
            it pays as dividends to its shareholders. In order to avoid a 4%
            federal excise tax, the Portfolio intends to distribute each year
            substantially all of its net income and gains.

             The Portfolio also intends to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolio's Statement of Additional Information for more
            information on taxes.

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolio described
            under the "Portfolio Summary" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolio from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolio. As with any mutual fund, investors in
            the Portfolio rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolio.

Securities  The Portfolio seeks maximum total return. The total return sought
Selection   by the Portfolio consists of both income earned on the Portfolio's
            investments and capital appreciation, if any, arising from
            increases in the market value of the Portfolio's holdings. Capital
            appreciation of fixed income securities generally results from
            decreases in market interest rates or improving credit
            fundamentals for a particular market sector or security.

             In selecting securities for the Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of the Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

13 PIMCO Variable Insurance Trust
<PAGE>

                PIMCO attempts to identify areas of the bond market that are
               undervalued relative to the rest of the market. PIMCO identifies
               these areas by grouping bonds into the following sectors: money
               markets, governments, corporates, mortgages, asset-backed and
               international. Sophisticated proprietary software then assists in
               evaluating sectors and pricing specific securities. Once
               investment opportunities are identified, PIMCO will shift assets
               among sectors depending upon changes in relative valuations and
               credit spreads. There is no guarantee that PIMCO's security
               selection techniques will produce the desired results.

U.S.           U.S. Government securities are obligations of and, in certain
Government     cases, guaranteed by, the U.S. Government, its agencies or
Securities     government-sponsored enterprises. U.S. Government Securities are
               subject to market and interest rate risk, and may be subject to
               varying degrees of credit risk. U.S. Government securities may
               include zero coupon securities, which do not distribute interest
               on a current basis and tend to be subject to greater market risk
               than interest-paying securities of similar maturities.

Muncipal       Municipal bonds are generally issued by states and local
Bonds          governments and their agencies, authorities and other
               instumentalities. Municipal bonds are subject to interest rate,
               credit and market risk. The ability of an issuer to make payments
               could be affected by litigation, legislation or other political
               events or the bankruptcy of the issuer. Lower rated municipal
               bonds are subject to greater credit and market risk than higher
               quality municipal bonds. The types of municipal bonds in which
               the Portfolio may invest include municipal lease obligations. The
               Portfolio may also invest in securities issued by entities whose
               underlying assets are municipal bonds.

Mortgage-      The Portfolio may invest all of its assets in mortgage- and
Related        asset-backed securities. Mortgage-related securities include
and Other      mortgage pass-through securities, collateralized mortgage
Asset-         obligations ("CMOs"), commercial mortgage-backed securities,
Backed         mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities     securities ("SMBSs") and other securities that directly or
               indirectly represent a participation in, or are secured by and
               payable from, mortgage loans on real property.

                The value of some mortgage- or asset-backed securities may be
               particularly sensitive to changes in prevailing interest rates.
               Early repayment of principal on some mortgage-related securities
               may expose a Portfolio to a lower rate of return upon
               reinvestment of principal. When interest rates rise, the value of
               a mortgage-related security generally will decline; however, when
               interest rates are declining, the value of mortgage-related
               securities with prepayment features may not increase as much as
               other fixed income securities. The rate of prepayments on
               underlying mortgages will affect the price and volatility of a
               mortgage-related security, and may shorten or extend the
               effective maturity of the security beyond what was anticipated at
               the time of purchase. If unanticipated rates of prepayment on
               underlying mortgages increase the effective maturity of a
               mortgage-related security, the volatility of the security can be
               expected to increase. The value of these securities may fluctuate
               in response to the market's perception of the creditworthiness of
               the issuers. Additionally, although mortgages and mortgage-
               related securities are generally supported by some form of
               government or private guarantee and/or insurance, there is no
               assurance that private guarantors or insurers will meet their
               obligations.

                One type of SMBS has one class receiving all of the interest
               from the mortgage assets (the interest-only, or "IO" class),
               while the other class will receive all of the principal (the
               principal-only, or "PO" class). The yield to maturity on an IO
               class is extremely sensitive to the rate of principal payments
               (including prepayments) on the underlying mortgage assets, and a
               rapid rate of principal payments may have a material adverse
               effect on a Portfolio's yield to maturity from these securities.
               A Portfolio may not invest more than 5% of its net assets in any
               combination of IO, PO, or inverse floater securities. The
               Portfolio may invest in other asset-backed securities that have
               been offered to investors.

Loan           The Portfolio may invest in fixed- and floating-rate loans, which
Participations investments generally will be in the form of loan participations
and            and assignments of portions of such loans. Participations and
Assignments    assignments involve special types of risk, including credit risk,
               interest rate risk, liquidity risk, and the risks of being a
               lender. If a Portfolio purchases a participation, it may only be
               able to enforce its rights through the lender, and may assume the
               credit risk of the lender in addition to the borrower.

                                                                  Prospectus  14
<PAGE>

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

Variable    Variable and floating rate securities provide for a periodic
and         adjustment in the interest rate paid on the obligations. The
Floating    Portfolio may invest in floating rate debt instruments
Rate        ("floaters") and engage in credit spread trades. While floaters
Securities  provide a certain degree of protection against rises in interest
            rates, a Portfolio will participate in any declines in interest
            rates as well. The Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. The Portfolio may not invest more than 5%
            of its assets in any combination of inverse floater, interest
            only, or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the

15 PIMCO Variable Insurance Trust
<PAGE>

            principal amount of an inflation-indexed bond will be considered
            taxable ordinary income, even though investors do not receive
            their principal until maturity.

Event-      The Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible The Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

             While a Fixed Income Portfolio intends to invest primarily in
            fixed income securities, it may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Foreign     Investing in the securities of issuers in any foreign country
(Non-       involves special risks and considerations not typically associated
U.S.)       with investing in U.S. companies. Shareholders should consider
Securities  carefully the substantial risks involved for portfolios that
            invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             The Portfolio may invest in sovereign debt issued by governments,
            their agencies or instrumentalities, or other government-related
            entities. Holders of sovereign debt may be requested to
            participate in the rescheduling of such debt and to extend further
            loans to governmental entities. In addition, there is no
            bankruptcy proceeding by which defaulted sovereign debt may be
            collected.

                                                                   Prospectus 16
<PAGE>

Repurchase  The Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.

Reverse     The Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             The Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, the Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. The Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives The Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. The Portfolio may invest
            all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolio may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolio.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

17 PIMCO Variable Insurance Trust
<PAGE>

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk, the Portfolio
            will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees
            (or, as permitted by applicable regulation, enter into certain
            offsetting positions) to cover its obligations under derivative
            instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolio may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring the Portfolio to increase its investment
Facilities  in a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            the Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       The Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Transactionssettlement date. This risk is in addition to the risk that the
            Portfolio's other assets will decline in the value.

                                                                   Prospectus 18
<PAGE>

            Therefore, these transactions may result in a form of leverage and
            increase the Portfolio's overall investment exposure. Typically,
            no income accrues on securities the Portfolio has committed to
            purchase prior to the time delivery of the securities is made,
            although the Portfolio may earn income on securities it has
            segregated to cover these positions.

Investment  The Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, the Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, the
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       The Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    The Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, the Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." The Portfolio may engage in frequent and active trading
            of portfolio securities to achieve its investment objective,
            particularly during periods of volatile market movements. High
            portfolio turnover (e.g., over 100%) involves correspondingly
            greater expenses to a Portfolio, including brokerage commissions
            or dealer mark-ups and other transaction costs on the sale of
            securities and reinvestments in other securities. Such sales may
            also result in realization of taxable capital gains, including
            short-term capital gains (which are generally taxed at ordinary

19 PIMCO Variable Insurance Trust
<PAGE>

            income tax rates). The trading costs and tax effects associated
            with portfolio turnover may adversely effect the Portfolio's
            performance.

Temporary   For temporary or defensive purposes, the Portfolio may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of the Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolio may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolio may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolio to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolio.

                                                                   Prospectus 20
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                           Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                      Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                     Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                      of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                        <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Long-Term U.S. Government
 Administrative Class
 12/31/1999(b)              $10.00     $0.36        $0.78 (a)     $(0.42)     $(0.36)      $0.00         $0.00         $0.00
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(b) Commenced operations on April 30, 1999.

21 PIMCO Variable Insurance Trust
<PAGE>




<TABLE>
<CAPTION>
                                                                     Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of      Investment
 Return                    Value               End     Expenses to    Income to   Portfolio
   of          Total        End    Total    of Period    Average       Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets     Net Assets    Rate
- -------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>           <C>          <C>


  $0.00       $(0.36)      $9.22   (4.28)%    $7,173      0.65%*(c)      5.55%*      294%
</TABLE>
- -------
*   Annualized.
(c) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.71%* for the
    period ended December 31, 1999.

                                                                   Prospectus 22
<PAGE>

            Other Information


Performance The following table provides information concerning the historical
Information total return performance of the Institutional Class shares of
of          certain series of PIMCO Funds: Pacific Investment Management
Similar     Series ("PIMS"). Each PIMS series has investment objectives,
Funds       policies and strategies substantially similar to those of its
            respective PIMCO Variable Insurance Trust ("PVIT") Portfolio and
            is currently managed by the same portfolio manager. While the
            investment objectives and policies of each PIMS series and its
            respective PVIT Portfolio are similar, they are not identical and
            the performance of the PIMS series and the PVIT Portfolio will
            vary. The data is provided to illustrate the past performance of
            PIMCO in managing a substantially similar investment portfolio and
            does not represent the past performance of the PVIT Portfolio or
            the future performance of the PVIT Portfolio or its portfolio
            manager. Consequently, potential investors should not consider
            this performance data as an indication of the future performance
            of the PVIT Portfolio or of its portfolio manager.

            The performance data shown below reflects the operating expenses
            of the Institutional Class of the PIMS series. The operating
            expenses of the Institutional Class of each PIMS series in the
            table are lower than the operating expenses of each Administrative
            Class of the corresponding PVIT Portfolio. As such, performance
            would have been lower if the PVIT Portfolio's expenses were used.
            In addition, the PIMS series, unlike the Portfolio, are not sold
            to Separate Accounts to fund Variable Contracts. As a result, the
            performance results presented below do not take into account
            charges or deductions against a Separate Account or Variable
            Contract for cost of insurance charges, premium loads,
            administrative fees, maintenance fees, premium taxes, mortality
            and expense risk charges, or other charges that may be incurred
            under a Variable Contract for which the Portfolio serves as an
            underlying investment vehicle. By contrast, Variable Contract
            Owners with contract value allocated to the Portfolio will be
            subject to charges and expenses relating to the Variable Contracts
            and Separate Accounts.

            Each PIMS series' performance data shown below is calculated in
            accordance with standards prescribed by the SEC for the
            calculation of average annual total return information. The
            investment results of the PIMS series presented below are
            unaudited and are not intended to predict or suggest results that
            might be experienced by the PIMS series or the Portfolio. Share
            prices and investment returns will fluctuate reflecting market
            conditions, as well as changes in company-specific fundamentals of
            portfolio securities. The performance data for the benchmark
            indices identified below does not reflect the fees or expenses of
            the PIMS series or the Portfolio.

                 Average Annual Total Return for Similar Series of PIMS
            Institutional Class and for Benchmark Indices for Periods Ended
                               December 31, 1999

                                                           Since   Inception
                                 1 Year  3 Years 5 Years Inception   Date
- ----------------------------------------------------------------------------
PIMCO Long-Term U.S. Government
 Fund/1/                         (7.99)   6.27    9.72     10.35    7/1/91
 Lehman Long-Term Treasury/2/    (8.74)   6.03    9.08

- -------
/1/Prior to July 1997 and April 2000 the Long-Term U.S. Government Fund was
  managed by different portfolio managers.
2 The Lehman Long-Term Treasury Index is an unmanaged index of U.S. Treasury
  issues with maturities greater than 10 years. It is not possible to invest
  directly in the index.

23 PIMCO Variable Insurance Trust
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

                                                                  Prospectus A-1
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings
& Poor's    Investment Grade
Ratings
Services     AAA: Debt rated AAA has the highest rating assigned by Standard &
            Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

A-2  PIMCO Variable Insurance Trust
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

                                                                  Prospectus A-3
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

A-4  PIMCO Variable Insurance Trust
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolio. The SAI and the financial statements included in the Portfolio's
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolio's annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about the Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.



PIMCO Funds

840 Newport Center Drive
Suite 300
Newport Beach, CA 92660


<PAGE>

PIMCO Funds Prospectus


PIMCO Variable Insurance Trust

April 1, 2000

Share Class

Adm Administrative

- --------------------------------------------------------------------------------
SHORT DURATION BOND PORTFOLIO
Low Duration Bond Portfolio

- --------------------------------------------------------------------------------
INTERNATIONAL BOND PORTFOLIO
Foreign Bond Portfolio

- --------------------------------------------------------------------------------


   This cover is not part of the Prospectus
                                                           [LOGO OF PIMCO FUNDS]


<PAGE>

            Prospectus


PIMCO            This Prospectus describes 2 separate investment portfolios
Variable         (the "Portfolios") offered by the PIMCO Variable Insurance
Insurance        Trust (the "Trust"). The Portfolios provide access to the
Trust            professional investment management services offered by
                 Pacific Investment Management Company ("PIMCO"). The
April 1,         investments made by the Portfolios at any given time are not
2000             expected to be the same as those made by other mutual funds
                 for which PIMCO acts as investment adviser, including mutual
Share            funds with investment objectives and strategies similar to
Class            those of the Portfolios. Accordingly, the performance of the
Administrative   Portfolios can be expected to vary from that of the other
                 mutual funds.


                 This Prospectus explains what you should know about the
                 Portfolios before you invest. Please read it carefully.

                 Shares of the Portfolios currently are sold to segregated asset
                 accounts ("Separate Accounts") of insurance companies that fund
                 variable annuity contracts and variable life insurance policies
                 ("Variable Contracts"). Assets in the Separate Account are
                 invested in shares of the Portfolios in accordance with
                 allocation instructions received from owners of the Variable
                 Contracts ("Variable Contract Owners"). Variable Contract
                 Owners do not deal directly with the Portfolios to purchase or
                 redeem shares. The allocation rights of Variable Contract
                 Owners are described in the accompanying Separate Account
                 prospectus. Shares of the Portfolios also may be sold to
                 qualified pension and retirement plans outside of the separate
                 account context.

                 This Prospectus should be read in conjunction with the
                 prospectus of the Separate Account. Both prospectuses should be
                 read carefully and retained for future reference.

                 The Securities and Exchange Commission has not approved or
                 disapproved these securities, or determined if this Prospectus
                 is truthful or complete. Any representation to the contrary is
                 a criminal offense.

1  PIMCO Variable Insurance Trust
<PAGE>

            Table of Contents

         Summary Information..............................................   3
         Portfolio Summaries
           Low Duration Bond Portfolio....................................   5
           Foreign Bond Portfolio.........................................   7
         Summary of Principal Risks.......................................   9
         Management of the Portfolios.....................................  11
         Investment Options...............................................  12
         Purchases and Redemptions........................................  13
         How Portfolio Shares are Priced..................................  14
         Tax Consequences.................................................  15
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  15
         Financial Highlights.............................................  25
         Appendix A--Description of Securities Ratings.................... A-1

                                                                  Prospectus 2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                   Credit            Non-U.S. Dollar
                                 Main Investments        Duration  Quality(1)        Denominated Securities(2)
- ---------------------------------------------------------------------------------------------------------------
 <C>           <C>               <S>                     <C>       <C>               <C>
 Short         Low Duration Bond Short maturity fixed    1-3 years B to Aaa; max 10% 0-20%(3)
 Duration                        income securities                 below Baa
 Bond
 Portfolio
- ---------------------------------------------------------------------------------------------------------------
 International Foreign Bond      Intermediate maturity   3-7 years B to Aaa; max     (greater than or =) 85%(4)
 Bond                            hedged non-U.S. fixed             10% below Baa
 Portfolio                       income securities
- ---------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  Each Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.
(4)  The percentage limitation relates to securities of foreign issuers,
     denominated in any currency.

3  PIMCO Variable Insurance Trust
<PAGE>

               Summary Information (continued)
Fixed          The "Fixed Income Portfolios" are the Low Duration Bond, and the
Income         Foreign Bond Portfolios. Each of the Fixed Income Portfolios
Instruments    differs from the other primarily in the length of the Portfolio's
               duration or the proportion of its investments in certain types of
               fixed income securities. Each Fixed Income Portfolio invests at
               least 65% of its assets in "Fixed Income Instruments," which as
               used in this Prospectus includes:

               . securities issued or guaranteed by the U.S. Government, its
                 agencies or government-sponsored enterprises ("U.S. Government
                 Securities");
               . corporate debt securities of U.S. and non-U.S. issuers,
                 including convertible securities and corporate commercial
                 paper;
               . mortgage-backed and other asset-backed securities;
               . inflation-indexed bonds issued both by governments and
                 corporations;
               . structured notes, including hybrid or "indexed" securities,
                 event-linked bonds and loan participations;
               . delayed funding loans and revolving credit facilities;
               . bank certificates of deposit, fixed time deposits and bankers'
                 acceptances;
               . repurchase agreements and reverse repurchase agreements;
               . debt securities issued by states or local governments and their
                 agencies, authorities and other instrumentalities;
               . obligations of non-U.S. governments or their subdivisions,
                 agencies and instrumentalities; and
               . obligations of international agencies or supranational
                 entities.

Duration       Duration is a measure of the expected life of a fixed income
               security that is used to determine the sensitivity of a
               security's price to changes in interest rates. The longer a
               security's duration, the more sensitive it will be to changes in
               interest rates. Similarly, a Portfolio with a longer average
               portfolio duration will be more sensitive to changes in interest
               rates than a Portfolio with a shorter average portfolio duration.

Credit         In this Prospectus, references are made to credit ratings of
Ratings        debt securities which measure an issuer's expected ability to pay
               principal and interest on time. Credit ratings are determined by
               rating organizations, such as Standard & Poor's Rating Service
               ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
               following terms are generally used to describe the credit quality
               of debt securities depending on the security's credit rating or,
               if unrated, credit quality as determined by PIMCO:

               . high quality
               . investment grade
               . below investment grade ("high yield securities" or "junk
                  bonds")

               For a further description of credit ratings, see "Appendix A--
               Description of Securities Ratings."

Portfolio      The Portfolios provide a broad range of investment choices. The
Descriptions,  following summaries identify each Portfolio's investment
Performance    objective, principal investments and strategies, principal risks,
and Fees       performance information and fees and expenses. A more detailed
               "Summary of Principal Risks" describing principal risks of
               investing in the Portfolios begins after the Portfolio Summaries.

               It is possible to lose money on investments in the Portfolios.

                An investment in a Portfolio is not a deposit of a bank and is
               not guaranteed or insured by the Federal Deposit Insurance
               Corporation or any other government agency.

                                                                  Prospectus 4
<PAGE>

            PIMCO Low Duration Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Short maturity       B to Aaa; maximum
and           Seeks maximum          fixed income         10% below Baa
Strategies    total return,          securities
              consistent with                             Dividend Frequency
              preservation of        Average Portfolio    Declared daily and
              capital and            Duration             distributed monthly
              prudent                1-3 years
              investment
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a one- to three-year time frame based on
            PIMCO's forecast for interest rates.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P, or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       . Derivatives Risk     . Currency Risk
                 Risk                .  Liquidity Risk      .  Leveraging
              .  Credit Risk         .  Mortgage Risk          Risk
              .  Market Risk         .  Foreign             .  Management
              .  Issuer Risk            Investment             Risk
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.

5  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Low Duration Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment______None)

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                      Total Annual                     Net Portfolio
                            Advisory Service Other    Portfolio Operating Expense      Operating
            Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -----------------------------------------------------------------------------------------
            <S>             <C>      <C>     <C>      <C>                 <C>          <C>
            Administrative  0.25%    0.15%   0.38%(1) 0.78%               (0.13%)      0.65%
            ----------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.13%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
            Share Class                         Year 1                                         Year 3
            -----------------------------------------------------------------------------------------
            <S>                                 <C>                                            <C>
            Administrative                      $66                                            $236
            -----------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>

            PIMCO Foreign Bond Portfolio

- --------------------------------------------------------------------------------
              Investment Objective   Portfolio Focus      Credit Quality
Principal     Seeks maximum          Intermediate         B to Aaa; maximum
Investments   total return,          maturity hedged      10% below Baa
and           consistent with        non-U.S. fixed
Strategies    preservation of        income securities
              capital and                                 Dividend Frequency
              prudent                Average Portfolio    Declared daily and
              investment             Duration
              management             3-7 years


            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 85% of its assets in
            Fixed Income Instruments of issuers located outside the United
            States, representing at least three foreign countries, which may
            be represented by futures contracts (including related options)
            with respect to such securities, and options on such securities.
            Such securities normally are denominated in major foreign
            currencies or baskets of foreign currencies (such as the euro).
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             PIMCO selects the Portfolio's foreign country and currency
            compositions based on an evaluation of various factors, including,
            but not limited to, relative interest rates, exchange rates,
            monetary and fiscal policies, trade and current account balances.
            The average portfolio duration of this Portfolio normally varies
            within a three- to seven-year time frame. The Portfolio invests
            primarily in investment grade debt securities, but may invest up
            to 10% of its assets in high yield securities ("junk bonds") rated
            B or higher by Moody's or S&P, or, if unrated, determined by PIMCO
            to be of comparable quality. The Portfolio is non-diversified,
            which means that it may concentrate its assets in a smaller number
            of issuers than a diversified Portfolio.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Foreign             .  Mortgage Risk
                 Risk                   Investment Risk     .  Derivatives Risk
              .  Credit Risk         .  Currency Risk       .  Leveraging Risk
              .  Market Risk         .  Issuer Non-         .  Management Risk
              .  Issuer Risk            Diversification
                                        Risk
                                     .  Liquidity Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.

7  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Foreign Bond Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                      Total Annual                     Net Portfolio
                            Advisory Service Other    Portfolio Operating Expense      Operating
            Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -----------------------------------------------------------------------------------------
            <S>             <C>      <C>     <C>      <C>                 <C>          <C>
            Administrative  0.25%    0.15%   0.85%(1) 1.25%               (0.15%)      1.10%(3)
            -----------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.50% administrative fee, 0.20%
                interest expense, and 0.15% representing the Portfolio's
                organizational expenses as attributed to the class and pro
                rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.90% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.
            (3) Ratio of net expenses to average net assets excluding interest
                expense is 0.90% for the Administrative Class.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
            Share Class                         Year 1                                         Year 3
            -------------------------------------------------------------------------------------------
            <S>                                 <C>                                            <C>
            Administrative                      $112                                           $382
            -------------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus 8
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset

9 PIMCO Variable Insurance Trust
<PAGE>

                and/or part of a strategy designed to reduce exposure to other
                risks, such as interest rate or currency risk. The Portfolios
                may also use derivatives for leverage, in which case their use
                would involve leveraging risk. A Portfolio's use of derivative
                instruments involves risks different from, or possibly greater
                than, the risks associated with investing directly in securities
                and other traditional investments. Derivatives are subject to a
                number of risks described elsewhere in this section, such as
                liquidity risk, interest rate risk, market risk, credit risk and
                management risk. They also involve the risk of mispricing or
                improper valuation and the risk that changes in the value of the
                derivative may not correlate perfectly with the underlying
                asset, rate or index. A Portfolio investing in a derivative
                instrument could lose more than the principal amount invested.
                Also, suitable derivative transactions may not be available in
                all circumstances and there can be no assurance that a Portfolio
                will engage in these transactions to reduce exposure to other
                risks when that would be beneficial.

Mortgage        A Portfolio that purchases mortgage-related securities is
Risk            subject to certain additional risks. Rising interest rates tend
                to extend the duration of mortgage-related securities, making
                them more sensitive to changes in interest rates. As a result,
                in a period of rising interest rates, a Portfolio that holds
                mortgage-related securities may exhibit additional volatility.
                This is known as extension risk. In addition, mortgage-related
                securities are subject to prepayment risk. When interest rates
                decline, borrowers may pay off their mortgages sooner than
                expected. This can reduce the returns of a Portfolio because the
                Portfolio will have to reinvest that money at the lower
                prevailing interest rates.

Foreign         A Portfolio that invests in foreign securities may experience
(Non-           more rapid and extreme changes in value than a Portfolio that
U.S.)           invests exclusively in securities of U.S. companies. The
Investment      securities markets of many foreign countries are relatively
Risk            small, with a limited number of companies representing a small
                number of industries. Additionally, issuers of foreign
                securities are usually not subject to the same degree of
                regulation as U.S. issuers. Reporting, accounting and auditing
                standards of foreign countries differ, in some cases
                significantly, from U.S. standards. Also, nationalization,
                expropriation or confiscatory taxation, currency blockage,
                political changes or diplomatic developments could adversely
                affect a Portfolio's investments in a foreign country. In the
                event of nationalization, expropriation or other confiscation, a
                Portfolio could lose its entire investment in foreign
                securities. Adverse conditions in a certain region can adversely
                affect securities of other countries whose economies appear to
                be unrelated. To the extent that a Portfolio invests a
                significant portion of its assets in a concentrated geographic
                area like Eastern Europe or Asia, the Portfolio will generally
                have more exposure to regional economic risks associated with
                foreign investments.

Currency        Portfolios that invest directly in foreign currencies or in
Risk            securities that trade in, and receive revenues in, foreign (non-
                U.S.) currencies are subject to the risk that those currencies
                will decline in value relative to the U.S. dollar, or, in the
                case of hedging positions, that the U.S. dollar will decline in
                value relative to the currency being hedged.

                Currency rates in foreign countries may fluctuate significantly
                over short periods of time for a number of reasons, including
                changes in interest rates, intervention (or the failure to
                intervene) by U.S. or foreign governments, central banks or
                supranational entities such as the International Monetary Fund,
                or by the imposition of currency controls or other political
                developments in the U.S. or abroad. As a result, a Portfolio's
                investments in foreign currency-denominated securities may
                reduce the returns of a Portfolio.

Issuer          Focusing investments in a small number of issuers, industries or
Non-            foreign currencies increases risk. Portfolios that are "non-
Diversification diversified" may invest a greater percentage of their assets in
Risk            the securities of a single issuer (such as bonds issued by a
                particular state) than Portfolios that are "diversified."
                Portfolios that invest in a relatively small number of issuers
                are more susceptible to risks associated with a single economic,
                political or regulatory occurrence than a more diversified
                portfolio might be. Some of those issuers also may present
                substantial credit

                                                                  Prospectus 10
<PAGE>

               or other risks. Similarly, a Portfolio may be more sensitive to
               adverse economic, business or political developments if it
               invests a substantial portion of its assets in the bonds of
               similar projects or from issuers in the same state.

Leveraging     Certain transactions may give rise to a form of leverage. Such
Risk           transactions may include, among others, reverse repurchase
               agreements, loans of portfolios securities, and the use of when-
               issued, delayed delivery or forward commitment transactions. The
               use of derivatives may also create leveraging risk. To mitigate
               leveraging risk, PIMCO will segregate liquid assets or otherwise
               cover the transactions that may give rise to such risk. The use
               of leverage may cause a Portfolio to liquidate portfolio
               positions when it may not be advantageous to do so to satisfy its
               obligations or to meet segregation requirements. Leverage,
               including borrowing, may cause a Portfolio to be more volatile
               than if the Portfolio had not been leveraged. This is because
               leverage tends to exaggerate the effect of any increase or
               decrease in the value of a Portfolio's portfolio securities.

Management     Each Portfolio is subject to management risk because it is an
Risk           actively managed investment portfolio. PIMCO and each individual
               portfolio manager will apply investment techniques and risk
               analyses in making investment decisions for the Portfolio, but
               there can be no guarantee that these will produce the desired
               results.

               Management of the Portfolios

Investment     PIMCO serves as investment adviser and the administrator (serving
Adviser        in its capacity as administrator, the "Administrator") for the
and            Portfolios. Subject to the supervision of the Board of Trustees,
Administrator  PIMCO is responsible for managing the investment activities of
              the Portfolios and the Portfolios' business affairs and other
              administrative matters.

                PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
               Beach, California 92660. Organized in 1971, PIMCO provides
               investment management and advisory services to private accounts
               of institutional and individual clients and to mutual funds. As
               of December 31, 1999, PIMCO had approximately $186 billion in
               assets under management.

Advisory       Each Portfolio pays PIMCO fees in return for providing investment
Fees           advisory services. For the fiscal year ended December 31, 1999,
               the Portfolios paid monthly advisory fees to PIMCO at the
               following annual rates (stated as a percentage of the average
               daily net assets of each Portfolio taken separately):

               Portfolio                    Advisory Fees
               --------------------------------------------
               Foreign Bond Portfolio           0.60%
               Low Duration Bond Portfolio      0.40%

                Effective April 1, 2000, the Portfolios pay monthly advisory
               fees to PIMCO at the following annual rates (stated as a
               percentage of the average daily net assets of each Portfolio
               taken separately):

               Portfolio                                   Advisory Fees
               ---------------------------------------------------------
               Low Duration Bond and Foreign Bond Portfolios      0.25%

Administrative Each Portfolio pays for the administrative services it requires
Fees           under a fee structure which is essentially fixed. Shareholders of
               each Portfolio pay an administrative fee to PIMCO, computed as a
               percentage of the Portfolio's assets attributable in the
               aggregate to that class of shares. PIMCO, in turn, provides or
               procures administrative services for shareholders and also bears
               the costs of various third-party services required by the
               Portfolios, including audit, custodial, portfolio accounting,
               legal, transfer agency and printing costs. The result of this fee
               structure is an expense level for shareholders of each Portfolio
               that, with limited exceptions, is precise and predictable under
               ordinary circumstances.

11 PIMCO Variable Insurance Trust
<PAGE>

             For the fiscal year ended December 31, 1999, the Portfolios paid
            PIMCO monthly administrative fees at the following annual rates:

            Portfolio                    Administrative Fees
            -------------------------------------------------
            Foreign Bond Portfolio              0.30%
            Low Duration Bond Portfolio         0.25%

             Effective April 1, 2000, the Portfolios pay PIMCO monthly
            administrative fees at the following annual rates:

            Portfolio                    Administrative Fees
            -------------------------------------------------
            Foreign Bond Portfolio              0.50%
            Low Duration Bond Portfolio         0.25%

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

<TABLE>
<CAPTION>
            Portfolio         Portfolio Manager  Since Recent Professional Experience
            ----------------------------------------------------------------------------------------
            <C>               <C>                <C>   <S>
            Low Duration Bond William H. Gross   2/99* Managing Director, Chief Investment Officer and
                                                       a founding partner of PIMCO.

            Foreign Bond      Lee R. Thomas, III 2/99* Managing Director and Senior International
                                                       Portfolio Manager, PIMCO. He joined PIMCO as a
                                                       Portfolio Manager in 1995, and has managed fixed
                                                       income accounts for various institutional
                                                       clients and funds since that time. Prior to
                                                       joining PIMCO, he was associated with Investcorp
                                                       as a member of the management committee
                                                       responsible for global securities and foreign
                                                       exchange trading.
</TABLE>
            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of each Portfolio. The Plan allows the
            Portfolios to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders;

                                                                  Prospectus 12
<PAGE>

            processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits a Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of a Portfolio's Administrative Class assets on
            an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account allocating assets
            to the Portfolios are required to monitor events to identify any
            material conflicts between variable annuity contract owners and
            variable life insurance policy owners, and would have to determine
            what action, if any, should be taken in the event of such a
            conflict. If such a conflict occurred, an insurance company
            participating in the Portfolios might be required to redeem the
            investment of one or more of its separate accounts from the
            Portfolios, which might force the Portfolios to sell securities at
            disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of

13 PIMCO Variable Insurance Trust
<PAGE>

            shares will be suspended when trading on the New York Stock
            Exchange is restricted or during an emergency which makes it
            impracticable for the Portfolios to dispose of their securities or
            to determine fairly the value of their net assets, or during any
            other period as permitted by the SEC for the protection of
            investors. In the event that a Portfolio ceases offering its
            shares, any investments allocated to the Portfolio will, subject
            to any necessary regulatory approvals, be invested in another
            Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Administrative Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

                                                                  Prospectus 14
<PAGE>

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  The Portfolios in this prospectus seek maximum total return. The
Selection   total return sought by a Portfolio consists of both income earned
            on a Portfolio's investments and capital appreciation, if any,
            arising from increases in the market value of a Portfolio's
            holdings. Capital appreciation of fixed income securities
            generally results from decreases in market interest rates or
            improving credit fundamentals for a particular market sector or
            security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion

15 PIMCO Variable Insurance Trust
<PAGE>

            of a Portfolio's assets committed to investment in securities with
            particular characteristics (such as quality, sector, interest rate
            or maturity) varies based on PIMCO's outlook for the U.S. and
            foreign economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

            U.S. Government securities are obligations of and, in certain
U.S.        cases, guaranteed by, the U.S. Government, its agencies or
Government  government-sponsored enterprises. U.S. Government Securities are
Securities  subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio may invest all of its assets in mortgage- and
Related     asset-backed securities. Mortgage-related securities include
and Other   mortgage pass-through securities, collateralized mortgage
Asset-      obligations ("CMOs"), commercial mortgage-backed securities,
Backed      mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities  securities ("SMBSs") and other securities that directly or
            indirectly represent a participation in, or are secured by and
            payable from, mortgage loans on real property.

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolios may
            invest in other asset-backed securities that have been offered to
            investors.


                                                                  Prospectus 16
<PAGE>

Loan           Certain Portfolios may invest in fixed- and floating-rate loans,
Participations which investments generally will be in the form of loan
and            participations and assignments of portions of such loans.
Assignments    Participations and assignments involve special types of risk,
               including credit risk, interest rate risk, liquidity risk, and
               the risks of being a lender. If a Portfolio purchases a
               participation, it may only be able to enforce its rights through
               the lender, and may assume the credit risk of the lender in
               addition to the borrower.

Corporate      Corporate debt securities are subject to the risk of the issuer's
Debt          inability to meet principal and interest payments on the
Securities    obligation and may also be subject to price volatility due to such
              factors as interest rate sensitivity, market perception of the
              credit-worthiness of the issuer and general market liquidity. When
              interest rates rise, the value of corporate debt securities can be
              expected to decline. Debt securities with longer maturities tend
              to be more sensitive to interest rate movements than those with
              shorter maturities.

High          Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield         ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities    Services ("S&P") are sometimes referred to as "high yield" or
              "junk" bonds. Investing in high yield securities involves special
              risks in addition to the risks associated with investments in
              higher-rated fixed income securities. While offering a greater
              potential opportunity for capital appreciation and higher yields,
              high yield securities typically entail greater potential price
              volatility and may be less liquid than higher-rated securities.
              High yield securities may be regarded as predominately speculative
              with respect to the issuer's continuing ability to meet principal
              and interest payments. They may also be more susceptible to real
              or perceived adverse economic and competitive industry conditions
              than higher-rated securities.

                . Credit Ratings and Unrated Securities. Rating agencies are
              private services that provide ratings of the credit quality of
              fixed income securities, including convertible securities.
              Appendix A to this Offering Memorandum describes the various
              ratings assigned to fixed income securities by Moody's and S&P.
              Ratings assigned by a rating agency are not absolute standards of
              credit quality and do not evaluate market risks. Rating agencies
              may fail to make timely changes in credit ratings and an issuer's
              current financial condition may be better or worse than a rating
              indicates. A Portfolio will not necessarily sell a security when
              its rating is reduced below its rating at the time of purchase.
              PIMCO does not rely solely on credit ratings, and develops its own
              analysis of issuer credit quality.

               A Portfolio may purchase unrated securities (which are not rated
              by a rating agency) if its portfolio manager determines that the
              security is of comparable quality to a rated security that the
              Portfolio may purchase. Unrated securities may be less liquid than
              comparable rated securities and involve the risk that the
              portfolio manager may not accurately evaluate the security's
              comparative credit rating. Analysis of the creditworthiness of
              issuers of high yield securities may be more complex than for
              issuers of higher-quality fixed income securities. To the extent
              that a Portfolio invests in high yield and/or unrated securities,
              the Portfolio's success in achieving its investment objective may
              depend more heavily on the portfolio manager's creditworthiness
              analysis than if the Portfolio invested exclusively in higher-
              quality and rated securities.

Variable      Variable and floating rate securities provide for a periodic
and           adjustment in the interest rate paid on the obligations. Each
Floating      Portfolio may invest in floating rate debt instruments
Rate          ("floaters") and engage in credit spread trades. While floaters
Securities    provide a certain degree of protection against rises in interest
              rates, a Portfolio will participate in any declines in interest
              rates as well. Each Portfolio may also invest in inverse floating
              rate debt instruments ("inverse floaters"). An inverse floater may
              exhibit greater price volatility than a fixed rate obligation of
              similar credit quality. A Portfolio may not invest more than 5% of
              its assets in any combination of inverse floater, interest only,
              or principal only securities.

Inflation-    Inflation-indexed bonds are fixed income securities whose
Indexed       principal value is periodically adjusted according to the rate of
Bonds         inflation. If the index measuring inflation falls, the principal
              value of inflation-indexed bonds will be adjusted downward, and
              consequently the interest payable on these securities (calculated
              with respect to a smaller principal amount) will be reduced.
              Repayment of the original bond principal upon maturity (as
              adjusted for inflation) is guaranteed in the case of U.S. Treasury
              inflation-indexed bonds. For bonds that do not provide a similar
              guarantee, the adjusted principal value of the bond repaid at
              maturity may be less than the original principal.

17 PIMCO Variable Insurance Trust
<PAGE>

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

            Each Portfolio may invest in "event-linked bonds," which are fixed
Event-      income securities for which the return of principal and payment of
Linked      interest is contingent on the non-occurrence of a specific
Bonds       "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Foreign     Investing in the securities of issuers in any foreign country
(Non-       involves special risks and considerations not typically associated
U.S.)       with investing in U.S. companies. Shareholders should consider
Securities  carefully the substantial risks involved for Portfolios that
            invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

                                                                Prospectus 18
<PAGE>

             Certain Portfolios also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. The Low Duration Bond Portfolio
            may invest up to 5% of its assets in securities of issuers based
            in countries with developing (or "emerging market") economies and
            the Foreign Bond Portfolio may invest up to 10% of its assets in
            such securities. Investing in emerging market securities imposes
            risks different from, or greater than, risks of investing in
            domestic securities or in foreign, developed countries. These
            risks include: smaller market capitalization of securities
            markets, which may suffer periods of relative illiquidity;
            significant price volatility; restrictions on foreign investment;
            possible repatriation of investment income and capital. In
            addition, foreign investors may be required to register the
            proceeds of sales; future economic or political crises could lead
            to price controls, forced mergers, expropriation or confiscatory
            taxation, seizure, nationalization, or creation of government
            monopolies. The currencies of emerging market countries may
            experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different clearance and settlement procedures, which may be unable
            to keep pace with the volume of securities transactions or
            otherwise make it difficult to engage in such transactions.
            Settlement problems may cause a Portfolio to miss attractive
            investment opportunities, hold a portion of its assets in cash
            pending investment, or be delayed in disposing of a portfolio
            security. Such a delay could result in possible liability to a
            purchaser of the security.

             Each Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolios' assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolios.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into
            forward foreign currency exchange contracts and invest in foreign
            currency futures contracts and options on foreign currencies and
            futures. A forward foreign currency exchange contract, which
            involves an obligation to purchase or sell a specific currency at
            a future date at a price set at the time of the contract, reduces
            a Portfolio's exposure to changes in the value of the currency it
            will deliver and increases its exposure to changes in the value of
            the currency it will receive for the duration of the contract. The
            effect on the value

19 PIMCO Variable Insurance Trust
<PAGE>

            of a Portfolio is similar to selling securities denominated in one
            currency and purchasing securities denominated in another
            currency. A contract to sell foreign currency would limit any
            potential gain which might be realized if the value of the hedged
            currency increases. A Portfolio may enter into these contracts to
            hedge against foreign exchange risk, to increase exposure to a
            foreign currency or to shift exposure to foreign currency
            fluctuations from one currency to another. Suitable hedging
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in such
            transactions at any given time or from time to time. Also, such
            transactions may not be successful and may eliminate any chance
            for a Portfolio to benefit from favorable fluctuations in relevant
            foreign currencies. A Portfolio may use one currency (or a basket
            of currencies) to hedge against adverse changes in the value of
            another currency (or a basket of currencies) when exchange rates
            between the two currencies are positively correlated. The
            Portfolio will segregate assets determined to be liquid by PIMCO
            in accordance with procedures established by the Board of Trustees
            to cover its obligations under forward foreign currency exchange
            contracts entered into for non-hedging purposes.

            Each Portfolio may enter into repurchase agreements, in which the
Repurchase  Portfolio purchases a security from a bank or broker-dealer and
Agreements  agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. Each Portfolio may
            invest all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolios may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

                                                                  Prospectus 20
<PAGE>

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk, each Portfolio
            will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees
            (or, as permitted by applicable regulation, enter into certain
            offsetting positions) to cover its obligations under derivative
            instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.


21 PIMCO Variable Insurance Trust
<PAGE>

Delayed      The Portfolios may also enter into, or acquire participations in,
Funding      delayed funding loans and revolving credit facilities, in which a
Loans and    lender agrees to make loans up to a maximum amount upon demand by
Revolving    the borrower during a specified term. These commitments may have
Credit       the effect of requiring a Portfolio to increase its investment in
Facilities   a company at a time when it might not otherwise decide to do so
             (including at a time when the company's financial condition makes
             it unlikely that such amounts will be repaid). To the extent that
             a Portfolio is committed to advance additional funds, it will
             segregate assets determined to be liquid by PIMCO in accordance
             with procedures established by the Board of Trustees in an amount
             sufficient to meet such commitments. Delayed funding loans and
             revolving credit facilities are subject to credit, interest rate
             and liquidity risk and the risks of being a lender.

When-        Each Portfolio may purchase securities which it is eligible to
Issued,      purchase on a when-issued basis, may purchase and sell such
Delayed      securities for delayed delivery and may make contracts to purchase
Delivery     such securities for a fixed price at a future date beyond normal
and          settlement time (forward commitments). When-issued transactions,
Forward      delayed delivery purchases and forward commitments involve a risk
Commitment   of loss if the value of the securities declines prior to the
Transactions settlement date. This risk is in addition to the risk that the
             Portfolio's other assets will decline in the value. Therefore,
             these transactions may result in a form of leverage and increase a
             Portfolio's overall investment exposure. Typically, no income
             accrues on securities a Portfolio has committed to purchase prior
             to the time delivery of the securities is made, although a
             Portfolio may earn income on securities it has segregated to cover
             these positions.

Investment   Each Portfolio may invest up to 10% of its assets in securities of
in Other     other investment companies, such as closed-end management
Investment   investment companies, or in pooled accounts or other investment
Companies    vehicles which invest in foreign markets. As a shareholder of any
             investment company, a Portfolio may indirectly bear service and
             other fees which are in addition to the fees the Portfolio pays its
             service providers.

              Subject to the restrictions and limitations of the 1940 Act, each
             Portfolio may, in the future, elect to pursue its investment
             objective by investing in one or more underlying investment
             vehicles or companies that have substantially similar investment
             objectives, policies and limitations as the Portfolio.

Short        Each Portfolio may make short sales as part of its overall
Sales        portfolio management strategies or to offset a potential decline
             in value of a security. A short sale involves the sale of a
             security that is borrowed from a broker or other institution to
             complete the sale. Short sales expose a Portfolio to the risk that
             it will be required to acquire, convert or exchange securities to
             replace the borrowed securities (also known as "covering" the short
             position) at a time when the securities sold short have appreciated
             in value, thus resulting in a loss to the Portfolio. A Portfolio
             making a short sale must segregate assets determined to be liquid
             by PIMCO in accordance with procedures established by the Board of
             Trustees or otherwise cover its position in a permissible manner.

Illiquid     Each Portfolio may invest up to 15% of its net assets in illiquid
Securities   securities. Certain illiquid securities may require pricing at fair
             value as determined in good faith under the supervision of the
             Board of Trustees. A portfolio manager may be subject to
             significant delays in disposing of illiquid securities, and
             transactions in illiquid securities may entail registration
             expenses and other transaction costs that are higher than those for
             transactions in liquid securities. The term "illiquid securities"
             for this purpose means securities that cannot be disposed of within
             seven days in the ordinary course of business at approximately the
             amount at which a Portfolio has valued the securities. Restricted
             securities, i.e., securities subject to legal or contractual
             restrictions on resale, may be illiquid. However, some restricted
             securities (such as securities issued pursuant to Rule 144A under
             the Securities Act of 1933 and certain commercial paper) may be
             treated as liquid, although they may be less liquid than registered
             securities traded on established secondary markets.


                                                                  Prospectus 22
<PAGE>

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

23 PIMCO Variable Insurance Trust
<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                  Prospectus 24
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Low Duration
 Administrative Class
 12/31/1999(b)         $10.00     $0.50        $(0.25)(a)    $ 0.25      $(0.51)      $0.00         $0.00        $ 0.00
Foreign Bond
 Administrative Class
 12/31/1999(b)         $10.00     $0.41        $(0.49)(a)    $(0.08)     $(0.41)      $0.00         $0.00        $(0.09)
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(b) Commenced operations on February 16, 1999.

25 PIMCO Variable Insurance Trust
<PAGE>




<TABLE>
<CAPTION>
                                                                        Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of         Investment
 Return                    Value               End     Expenses to       Income to   Portfolio
   of          Total        End    Total    of Period    Average          Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets        Net Assets    Rate
- ----------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>              <C>          <C>


  $0.00       $(0.51)      $9.74    2.56 %    $5,149      0.65%*(c)         5.74%*       11%


  $0.00       $(0.50)      $9.42   (0.78)%    $5,215      1.10%*(d)(e)      4.83%*      285%
</TABLE>
- -------
*   Annualized.
(c) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.78%* for the
    period ended December 31, 1999.
(d) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 1.25%* for the
    period ended December 31, 1999.
(e) Ratio of net expenses to average net assets excluding interest expense is
    0.90%.

                                                                  Prospectus 26
<PAGE>

            Other Information


Performance The following table provides information concerning the historical
Information total return performance of the Institutional Class shares of
of          certain series of PIMCO Funds: Pacific Investment Management
Similar     Series ("PIMS"). Each PIMS series has investment objectives,
Funds       policies and strategies substantially similar to those of its
            respective PIMCO Variable Insurance Trust ("PVIT") Portfolio and
            is currently managed by the same portfolio manager. While the
            investment objectives and policies of each PIMS series and its
            respective PVIT Portfolio are similar, they are not identical and
            the performance of the PIMS series and the PVIT Portfolio will
            vary. The data is provided to illustrate the past performance of
            PIMCO in managing a substantially similar investment portfolio and
            does not represent the past performance of any of the PVIT
            Portfolios or the future performance of any PVIT Portfolio or its
            portfolio manager. Consequently, potential investors should not
            consider this performance data as an indication of the future
            performance of any PVIT Portfolio or of its portfolio manager.

            The performance data shown below reflects the operating expenses
            of the Institutional Class of the PIMS series. The operating
            expenses for the Institutional Class of the PIMS Low Duration Bond
            and Foreign Bond Funds are lower than the operating expenses for
            the Institutional Class of the corresponding PVIT Portfolios.
            Furthermore, the operating expenses of the Institutional Class of
            each PIMS series in the table are lower than the operating
            expenses of each Administrative Class of the corresponding PVIT
            Portfolio. As such, performance would have been lower if the PVIT
            Portfolios' expenses were used. In addition, the PIMS series,
            unlike the Portfolios, are not sold to Separate Accounts to fund
            Variable Contracts. As a result, the performance results presented
            below do not take into account charges or deductions against a
            Separate Account or Variable Contract for cost of insurance
            charges, premium loads, administrative fees, maintenance fees,
            premium taxes, mortality and expense risk charges, or other
            charges that may be incurred under a Variable Contract for which
            the Portfolio serves as an underlying investment vehicle. By
            contrast, Variable Contract Owners with contract value allocated
            to the Portfolios will be subject to charges and expenses relating
            to the Variable Contracts and Separate Accounts.

            Each PIMS series' performance data shown below is calculated in
            accordance with standards prescribed by the SEC for the
            calculation of average annual total return information. The
            investment results of the PIMS series presented below are
            unaudited and are not intended to predict or suggest results that
            might be experienced by the PIMS series or the Portfolios. Share
            prices and investment returns will fluctuate reflecting market
            conditions, as well as changes in company-specific fundamentals of
            portfolio securities. The performance data for the benchmark
            indices identified below does not reflect the fees or expenses of
            the PIMS series or the Portfolios.


27 PIMCO Variable Insurance Trust
<PAGE>

   Average Annual Total Return for Similar Series of PIMS Institutional Class
         and for Benchmark Indices for Periods Ended December 31, 1999

<TABLE>
<CAPTION>
                                                            Since   Inception
                                   1 Year 3 Years 5 Years Inception   Date
- -----------------------------------------------------------------------------
<S>                                <C>    <C>     <C>     <C>       <C>
PIMCO Low Duration Fund             2.97   6.10     7.25    7.80     5/11/87
 Merrill Lynch 1-3 yr. Treasury/1/  3.06   5.56     6.51
PIMCO Foreign Bond Fund/2/          1.56   7.00    12.04    9.76     12/3/92
 J.P. Morgan Non-U.S. (Hedged)/3/   2.48   8.54    11.14
</TABLE>
- -------
/1/The Merrill Lynch 1-3 Year Treasury Index consists of all public U.S.
  Treasury obligations having maturities from one to 2.99 years. It is not
  possible to invest directly in the index.
/2/Prior to July 1995, the Foreign Bond Fund was managed by a different
  portfolio manager.
/3/The J.P. Morgan Non-U.S. (Hedged) Index is an unmanaged market index
  representative of the total return performance in U.S. dollars of major non-
  U.S. bond markets. It is not possible to invest directly in the index.

                                                                  Prospectus 28
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

A-1 PIMCO Variable Insurance Trust

<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

                                                                  Prospectus A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

A-3 PIMCO Variable Insurance Trust
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

                                                                  Prospectus A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.


[LOGO OF PIMCO FUNDS]


PIMCO Funds

840 Newport Center Drive
Suite 300
Newport Beach, CA 92660


<PAGE>


[LOGO]              PIMCO Funds Prospectus

PIMCO               ------------------------------------------------------------
Variable            INTERMEDIATE DURATION BOND PORTFOLIO
Insurance           Total Return Bond Portfolio
Trust
                    ------------------------------------------------------------
April 1, 2000       LONG DURATION BOND PORTFOLIO
                    Long-Term U.S. Government Bond Portfolio
Share Class

Adm Administrative  This cover is not part of the Prospectus

                                                           [LOGO OF PIMCO FUNDS]


<PAGE>

            Prospectus


PIMCO       This Prospectus describes the Total Return Bond and Long-Term U.S.
Variable    Government Bond Portfolios (the "Portfolios") which are separate
Insurance   investment portfolios offered by the PIMCO Variable Insurance
Trust       Trust (the "Trust"). The Portfolios provide access to the
            professional investment management services offered by Pacific
April 1,    Investment Management Company ("PIMCO"). The investments made by
2000        the Portfolios at any given time are not expected to be the same
            as those made by other mutual funds for which PIMCO acts as
Share       investment adviser, including mutual funds with investment
Class       objectives and strategies similar to those of the Portfolios.
            Accordingly, the performance of the Portfolios can be expected to
Admini-     vary from that of the other mutual funds.
strative
            This Prospectus explains what you should know about the Portfolios
            before you invest. Please read it carefully.

            Shares of the Portfolios currently are sold to segregated asset
            accounts ("Separate Accounts") of insurance companies that fund
            variable annuity contracts and variable life insurance policies
            ("Variable Contracts"). Assets in the Separate Account are
            invested in shares of the Portfolios in accordance with allocation
            instructions received from owners of the Variable Contracts
            ("Variable Contract Owners"). Variable Contract Owners do not deal
            directly with the Portfolios to purchase or redeem shares. The
            allocation rights of Variable Contract Owners are described in the
            accompanying Separate Account prospectus. Shares of the Portfolios
            also may be sold to qualified pension and retirement plans outside
            of the separate account context.

            This Prospectus should be read in conjunction with the prospectus
            of the Separate Account. Both prospectuses should be read
            carefully and retained for future reference.

            The Securities and Exchange Commission has not approved or
            disapproved these securities, or determined if this Prospectus is
            truthful or complete. Any representation to the contrary is a
            criminal offense.

   PIMCO Variable Insurance Trust
1
<PAGE>

            Table of Contents

<TABLE>
         <S>                                                               <C>
         Summary Information..............................................   3
         Portfolio Summaries..............................................   5
           Total Return Portfolio.........................................   5
           Long-Term U.S. Government Portfolio............................   7
         Summary of Principal Risks.......................................   9
         Management of the Portfolios.....................................  12
         Investment Options...............................................  13
         Purchases and Redemptions........................................  14
         How Portfolio Shares are Priced..................................  15
         Tax Consequences.................................................  16
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  17
         Financial Highlights.............................................  26
         Appendix A--Description of Securities Ratings.................... A-1
</TABLE>

                                                                  Prospectus
                                                                               2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                                          Non-U.S.
                                                                                                          Dollar
                                                                                        Credit            Denominated
                                 Main Investments           Duration                    Quality(1)        Securities
- ------------------------------------------------------------------------------------------------------------------------
 <C>           <C>               <S>                        <C>                         <C>               <C>
 Intermediate  Total Return Bond Intermediate maturity      3-6 years                   B to Aaa; max 10%    0-20%(2)(3)
 Duration                        fixed income securities                                below Baa
 Bond
 Portfolio
- ------------------------------------------------------------------------------------------------------------------------
 Long          Long-Term         Long-term maturity fixed   (greater than or =) 8 years A to Aaa             0%
 Duration      U.S. Government   income securities
 Bond
 Portfolio
- ------------------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  The Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)
Fixed       The "Fixed Income Portfolios" are the Total Return Bond and Long-
Income      Term U.S. Government Bond Portfolios. Each of the Fixed Income
Instruments Portfolios differs from the other primarily in the length of the
            Portfolio's duration or the proportion of its investments in
            certain types of fixed income securities. Each Fixed Income
            Portfolio invests at least 65% of its assets in "Fixed Income
            Instruments," which as used in this Prospectus includes:

            . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio   The Portfolios provide a broad range of investment choices. The
Descrip-    following summaries identify each Portfolio's investment
tions,      objective, principal investments and strategies, principal risks,
Perfor-     performance information and fees and expenses. A more detailed
mance       "Summary of Principal Risks" describing principal risks of
and Fees    investing in the Portfolios begins after the Portfolio Summaries.

             It is possible to lose money on investments in the Portfolios.

             An investment in a Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.

                                                                  Prospectus
                                                                               4
<PAGE>

            PIMCO Total Return Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Intermediate         B to Aaa; maximum
and           Seeks maximum          maturity fixed       10% below Baa
Strategies    total return,          income
              consistent with        securities           Dividend Frequency
              preservation of                             Declared daily and
              capital and            Average Portfolio    distributed monthly
              prudent                Duration
              investment             3-6 years
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a three- to six-year time frame based on
            PIMCO's forecast for interest rates.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Derivatives         .  Currency Risk
                 Risk                   Risk                .  Leveraging
              .  Credit Risk         .  Liquidity Risk         Risk
              .  Market Risk         .  Mortgage Risk       .  Management
              .  Issuer Risk         .  Foreign                Risk
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


5  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Total Return Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

<TABLE>
<S>                                                         <C>
                              [GRAPH]                       Highest and Lowest Quarter Returns
                                                            (for periods shown in the bar chart)
                           1998     8.61%                   ------------------------------------
                           1999   (0.58)%                   Highest (3rd Qtr. '98)         5.43%
                                                            ------------------------------------
                                                            Lowest (2nd Qtr. '99)        (0.94%)
</TABLE>

                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                    Portfolio
                                                    Inception
                                            1 Year  (12/31/97)
            --------------------------------------------------
            <S>                             <C>     <C>
            Administrative Class            (0.58%) 3.91%
            --------------------------------------------------
            Lehman Aggregate Bond Index(1)  (0.82%) 3.82%
            --------------------------------------------------
</TABLE>

            (1) The Lehman Brothers Aggregate Bond Index is an unmanaged index
                of investment grade, U.S. dollar-denominated fixed income
                securities of domestic issuers having a maturity greater than
                one year. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                      Total Annual
                                                      Portfolio                 Net Portfolio
                            Advisory Service Other    Operating    Expense      Operating
            Share Class     Fees     Fees    Expenses Expenses     Reduction(2) Expenses
            ---------------------------------------------------------------------------------
            <S>             <C>      <C>     <C>      <C>          <C>          <C>
            Administrative  0.25%    0.15%   0.29%(1) 0.69%        (0.04%)      0.65%
            ---------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.04%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
            Share Class           Year 1             Year 3             Year 5             Year 10
            --------------------------------------------------------------------------------------
            <S>                   <C>                <C>                <C>                <C>
            Administrative        $66                $217               $380               $855
            --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>

            PIMCO Long-Term U.S. Government Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Long-term            A to Aaa
and           Seeks maximum          maturity
Strategies    total return,          fixed income         Dividend Frequency
              consistent with        securities           Declared daily and
              preservation of                             distributed monthly
              capital and            Average Portfolio
              prudent                Duration
              investment             (greater than or
              management             =) 8 years

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of fixed income securities that are issued
            or guaranteed by the U.S. Government, its agencies or government-
            sponsored enterprises ("U.S. Government Securities"). Assets not
            invested in U.S. Government Securities may be invested in other
            types of Fixed Income Instruments. The Portfolio also may obtain
            exposure to U.S. Government Securities through the use of futures
            contracts (including related options) with respect to such
            securities, and options on such securities, when PIMCO deems it
            appropriate to do so. While PIMCO may invest in derivatives at any
            time it deems appropriate, it will generally do so when it
            believes that U.S. Government Securities are overvalued relative
            to derivative instruments. This Portfolio will normally have a
            minimum average portfolio duration of eight years. For point of
            reference, the dollar-weighted average portfolio maturity of the
            Portfolio is normally expected to be more than ten years.

             The Portfolio's investments in Fixed Income Instruments are
            limited to those of investment grade U.S. dollar-denominated
            securities of U.S. issuers that are rated at least A by Moody's or
            S&P, or, if unrated, determined by PIMCO to be of comparable
            quality. In addition, the Portfolio may only invest up to 10% of
            its assets in securities rated A by Moody's or S&P, and may only
            invest up to 25% of its assets in securities rated Aa by Moody's
            or AA by S&P.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage-backed securities. The Portfolio may
            lend its portfolio securities to brokers, dealers and other
            financial institutions to earn income. The Portfolio may seek to
            obtain market exposure to the securities in which it primarily
            invests by entering into a series of purchase and sale contracts
            or by using other investment techniques (such as buy backs or
            dollar rolls). The "total return" sought by the Portfolio consists
            of income earned on the Portfolio's investments, plus capital
            appreciation, if any, which generally arises from decreases in
            interest rates or improving credit fundamentals for a particular
            sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Issuer Risk         .  Leveraging Risk
                 Risk                .  Derivatives Risk    .  Management Risk
              .  Credit Risk         .  Mortgage Risk
              .  Market Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.


7  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Long-Term U.S. Government Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)      None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                      Total Annual                     Net Portfolio
                            Advisory Service Other    Portfolio Operating Expense      Operating
            Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            ----------------------------------------------------------------------------------------
            <S>             <C>      <C>     <C>      <C>                 <C>          <C>
            Administrative  0.25%    0.15%   0.31%(1) 0.71%               (0.06%)          0.65%
            ----------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.06%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
            Share Class                         Year 1                                         Year 3
            -----------------------------------------------------------------------------------------
            <S>                                 <C>                                            <C>
            Administrative                      $66                                            $221
            -----------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   8
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

   PIMCO Variable Insurance Trust
9
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolios may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    Portfolios that invest directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies are subject to the risk that those currencies
            will decline in value relative to the U.S. dollar, or, in the case
            of hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary Fund, or
            by the

                                                                  Prospectus
                                                                              10
<PAGE>

            imposition of currency controls or other political developments in
            the U.S. or abroad. As a result, a Portfolio's investments in
            foreign currency-denominated securities may reduce the returns of
            a Portfolio.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

   PIMCO Variable Insurance Trust
11
<PAGE>

            Management of the Portfolios

Investment  PIMCO serves as investment adviser and the administrator (serving
Adviser     in its capacity as administrator, the "Administrator") for the
and         Portfolios. Subject to the supervision of the Board of Trustees,
Admini-     PIMCO is responsible for managing the investment activities of the
strator     Portfolios and the Portfolios' business affairs and other
            administrative matters.

             PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
            Beach, California 92660. Organized in 1971, PIMCO provides
            investment management and advisory services to private accounts of
            institutional and individual clients and to mutual funds. As of
            December 31, 1999, PIMCO had approximately $186 billion in assets
            under management.

Advisory    Each Portfolio pays PIMCO fees in return for providing investment
Fees        advisory services. For the fiscal year ended December 31, 1999,
            the Portfolios paid monthly advisory fees to PIMCO at the
            following annual rates (stated as a percentage of the average
            daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
            Portfolio       Advisory Fees
            -----------------------------
            <S>             <C>
            All Portfolios      0.40%
</TABLE>

             Effective April 1, 2000, the Portfolios pay monthly advisory fees
            to PIMCO at the following annual rates (stated as a percentage of
            the average daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
            Portfolio       Advisory Fees
            -----------------------------
            <S>             <C>
            All Portfolios      0.25%
</TABLE>

Admini-     Each Portfolio pays for the administrative services it requires
strative    under a fee structure which is essentially fixed. Shareholders of
Fees        each Portfolio pay an administrative fee to PIMCO, computed as a
            percentage of the Portfolio's assets attributable in the aggregate
            to that class of shares. PIMCO, in turn, provides or procures
            administrative services for shareholders and also bears the costs
            of various third-party services required by the Portfolios,
            including audit, custodial, portfolio accounting, legal, transfer
            agency and printing costs. The result of this fee structure is an
            expense level for shareholders of each Portfolio that, with
            limited exceptions, is precise and predictable under ordinary
            circumstances.

             For the fiscal year ended December 31, 1999, the Portfolios paid
            PIMCO monthly administrative fees at the following annual rates:

<TABLE>
<CAPTION>
            Portfolio       Administrative Fees
            -----------------------------------
            <S>             <C>
            All Portfolios         0.25%
</TABLE>

             Effective April 1, 2000, the Portfolios pay PIMCO monthly
            administrative fees at the following annual rates:

<TABLE>
<CAPTION>
            Portfolio       Administrative Fees
            -----------------------------------
            <S>             <C>
            All Portfolios         0.25%
</TABLE>

                                                                  Prospectus
                                                                              12
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

<TABLE>
<CAPTION>
                                           Portfolio               Recent Professional
            Portfolio                      Manager          Since  Experience
            ----------------------------------------------------------------------------

            <C>                            <C>              <C>    <S>
            Total Return Bond              William H. Gross 12/97* Managing Director, Chief
                                                                   Investment Officer and a
                                                                   founding partner of
                                                                   PIMCO.




            Long-Term U.S.                 James M. Keller   4/00  Executive Vice
            Government Bond                                        President, PIMCO. He
                                                                   joined PIMCO as a
                                                                   Portfolio Manager in
                                                                   1996, and has managed
                                                                   fixed income accounts
                                                                   for various
                                                                   institutional clients
                                                                   since that time.
</TABLE>
            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

   PIMCO Variable Insurance Trust
13
<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of each Portfolio. The Plan allows the
            Portfolios to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits a Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of a Portfolio's Administrative Class assets on
            an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account

                                                                  Prospectus
                                                                              14
<PAGE>

            allocating assets to the Portfolios are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolios might be
            required to redeem the investment of one or more of its separate
            accounts from the Portfolios, which might force the Portfolios to
            sell securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolios to dispose of
            their securities or to determine fairly the value of their net
            assets, or during any other period as permitted by the SEC for the
            protection of investors. In the event that a Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Administrative Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.


15 PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus
                                                                              16
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  Most of the Portfolios in this prospectus seek maximum total
Selection   return. The total return sought by a Portfolio consists of both
            income earned on a Portfolio's investments and capital
            appreciation, if any, arising from increases in the market value
            of a Portfolio's holdings. Capital appreciation of fixed income
            securities generally results from decreases in market interest
            rates or improving credit fundamentals for a particular market
            sector or security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of a Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio may invest all of its assets in mortgage- and
Related     asset-backed securities. Mortgage-related securities include
and Other   mortgage pass-through securities, collateralized mortgage
Asset-      obligations ("CMOs"), commercial mortgage-backed securities,
Backed      mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities  securities ("SMBSs") and other securities that directly or
            indirectly represent a participation in, or are secured by and
            payable from, mortgage loans on real property.

   PIMCO Variable Insurance Trust
17
<PAGE>

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolios may
            invest in other asset-backed securities that have been offered to
            investors.

Loan        Certain Portfolios may invest in fixed- and floating-rate loans,
Partici-    which investments generally will be in the form of loan
pations     participations and assignments of portions of such loans.
and         Participations and assignments involve special types of risk,
Assign-     including credit risk, interest rate risk, liquidity risk, and the
ments       risks of being a lender. If a Portfolio purchases a participation,
            it may only be able to enforce its rights through the lender, and
            may assume the credit risk of the lender in addition to the
            borrower.

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

                                                                  Prospectus
                                                                              18
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

            Variable and floating rate securities provide for a periodic
Variable    adjustment in the interest rate paid on the obligations. Each
and         Portfolio may invest in floating rate debt instruments
Floating    ("floaters") and engage in credit spread trades. While floaters
Rate        provide a certain degree of protection against rises in interest
Securities  rates, a Portfolio will participate in any declines in interest
            rates as well. Each Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. A Portfolio may not invest more than 5% of
            its assets in any combination of inverse floater, interest only,
            or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      Each Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

   PIMCO Variable Insurance Trust
19
<PAGE>

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

            Investing in the securities of issuers in any foreign country
Foreign     involves special risks and considerations not typically associated
(Non-       with investing in U.S. companies. Shareholders should consider
U.S.)       carefully the substantial risks involved for Portfolios that
Securities  invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             Certain Portfolios also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. Each Portfolio that may invest in
            foreign securities, may invest up to 10% of its assets in
            securities of issuers based in countries with developing (or
            "emerging market") economies. Investing in emerging market
            securities imposes risks different from, or greater than, risks of
            investing in domestic securities or in foreign, developed
            countries. These risks include: smaller market capitalization of
            securities markets, which may suffer periods of relative
            illiquidity; significant price volatility; restrictions on foreign
            investment; possible repatriation of investment income and
            capital. In addition, foreign investors may be required to
            register the proceeds of sales; future economic or political
            crises could lead to price controls, forced mergers, expropriation
            or confiscatory taxation, seizure, nationalization, or creation of
            government monopolies. The currencies of emerging market countries
            may experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                Prospectus
                                                                              20
<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             The Total Return Bond Portfolio may invest in Brady Bonds, which
            are securities created through the exchange of existing commercial
            bank loans to sovereign entities for new obligations in connection
            with a debt restructuring. Investments in Brady Bonds may be
            viewed as speculative. Brady Bonds acquired by the Portfolio may
            be subject to restructuring arrangements or to requests for new
            credit, which may cause the Portfolio to suffer a loss of interest
            or principal on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolios' assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolios.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into forward
            foreign currency exchange contracts and invest in foreign currency
            futures contracts and options on foreign currencies and futures. A
            forward foreign currency exchange contract, which involves an
            obligation to purchase or sell a specific currency at a future date
            at a price set at the time of the contract, reduces a Portfolio's
            exposure to changes in the value of the currency it will deliver and
            increases its exposure to changes in the value of the currency it
            will receive for the duration of the contract. The effect on the
            value of a Portfolio is similar to selling securities denominated in
            one currency and purchasing securities denominated in another
            currency. A contract to sell foreign currency would limit any
            potential gain which might be realized if the value of the hedged
            currency increases. A Portfolio may enter into these contracts to
            hedge against foreign exchange risk, to increase exposure to a
            foreign currency or to shift exposure to foreign currency
            fluctuations from one currency to another. Suitable hedging
            transactions may not be available in all circumstances and there can
            be no assurance that a Portfolio will engage in such transactions at
            any given time or from time to time. Also, such transactions may not
            be successful and may eliminate any chance for a Portfolio to
            benefit from favorable fluctuations in relevant foreign currencies.
            A Portfolio may use one currency (or a basket of currencies) to
            hedge against adverse changes in the value of another currency (or a
            basket of currencies) when exchange rates between the two currencies
            are positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations under
            forward foreign currency exchange contracts entered into for non-
            hedging purposes.

Repurchase  Each Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


   PIMCO Variable Insurance Trust
21
<PAGE>

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. Each Portfolio may
            invest all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolios may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus
                                                                              22
<PAGE>

            each Portfolio will segregate assets determined to be liquid by
            PIMCO in accordance with procedures established by the Board of
            Trustees (or, as permitted by applicable regulation, enter into
            certain offsetting positions) to cover its obligations under
            derivative instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolios may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring a Portfolio to increase its investment in
Facilities  a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            a Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       Each Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Trans-      settlement date. This risk is in addition to the risk that the
actions     Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase a
            Portfolio's overall investment exposure. Typically, no income
            accrues on securities a Portfolio has committed to purchase prior
            to the time delivery of the securities is made, although a
            Portfolio may earn income on securities it has segregated to cover
            these positions.


   PIMCO Variable Insurance Trust
23
<PAGE>

Investment  Each Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, a Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, each
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       Each Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    Each Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.


                                                                   Prospectus
                                                                              24
<PAGE>

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

   PIMCO Variable Insurance Trust
25
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Total Return
 Administrative Class
 12/31/1999            $10.09     $0.58        $(0.64)(a)    $(0.06)     $(0.58)      $0.00        $ 0.00         $0.00
 12/31/1998(c)          10.00      0.56          0.28 (a)      0.84       (0.56)       0.00         (0.19)         0.00
Long-Term U.S. Government
 Administrative Class
 12/31/1999(d)         $10.00     $0.36        $ 0.78 (a)    $(0.42)     $(0.36)      $0.00        $ 0.00         $0.00
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(c) Commenced operations on December 31, 1997.
(d) Commenced operations on April 30, 1999.

                                                                  Prospectus
                                                                              26
<PAGE>




<TABLE>
<CAPTION>
                                                                     Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of      Investment
 Return                    Value               End     Expenses to    Income to   Portfolio
   of          Total        End    Total    of Period    Average       Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets     Net Assets    Rate
- -------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>           <C>          <C>


  $0.00       $(0.58)     $ 9.45   (0.58)%    $3,877      0.65% (b)      5.96%       102%
   0.00        (0.75)      10.09    8.61       3,259      0.65           5.55        139


  $0.00       $(0.36)     $ 9.22   (4.28)%    $7,173      0.65%*(e)      5.55%*      294%
</TABLE>
- -------
*   Annualized.
(b) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.69% for the
    period ended December 31, 1999.
(e) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.71%* for the
    period ended December 31, 1999.

   PIMCO Variable Insurance Trust
27
<PAGE>

            Other Information


Performance The following table provides information concerning the historical
Information total return performance of the Institutional Class shares of one
of          series of PIMCO Funds: Pacific Investment Management Series
Similar     ("PIMS"). The PIMS series has investment objectives, policies and
Funds       strategies substantially similar to those of its respective PIMCO
            Variable Insurance Trust ("PVIT") Portfolio and is currently
            managed by the same portfolio manager. While the investment
            objectives and policies of the PIMS series and its respective PVIT
            Portfolio are similar, they are not identical and the performance
            of the PIMS series and the PVIT Portfolio will vary. The data is
            provided to illustrate the past performance of PIMCO in managing a
            substantially similar investment portfolio and does not represent
            the past performance of the PVIT Portfolio or the future
            performance of the PVIT Portfolio or its portfolio manager.
            Consequently, potential investors should not consider this
            performance data as an indication of the future performance of the
            PVIT Portfolio or of its portfolio manager.

            The performance data shown below reflects the operating expenses
            of the Institutional Class of the PIMS series. The operating
            expenses of the Institutional Class of the PIMS series in the
            table are lower than the operating expenses of the Administrative
            Class of the corresponding PVIT Portfolio. As such, performance
            would have been lower if the PVIT Portfolio's expenses were used.
            In addition, the PIMS series, unlike the Portfolios, are not sold
            to Separate Accounts to fund Variable Contracts. As a result, the
            performance results presented below do not take into account
            charges or deductions against a Separate Account or Variable
            Contract for cost of insurance charges, premium loads,
            administrative fees, maintenance fees, premium taxes, mortality
            and expense risk charges, or other charges that may be incurred
            under a Variable Contract for which the Portfolio serves as an
            underlying investment vehicle. By contrast, Variable Contract
            Owners with contract value allocated to the Portfolios will be
            subject to charges and expenses relating to the Variable Contracts
            and Separate Accounts.

            The PIMS series' performance data shown below is calculated in
            accordance with standards prescribed by the SEC for the
            calculation of average annual total return information. The
            investment results of the PIMS series presented below are
            unaudited and are not intended to predict or suggest results that
            might be experienced by the PIMS series or the Portfolio. Share
            prices and investment returns will fluctuate reflecting market
            conditions, as well as changes in company-specific fundamentals of
            portfolio securities. The performance data for the benchmark index
            identified below does not reflect the fees or expenses of the PIMS
            series or the Portfolio.

   Average Annual Total Return for Similar Series of PIMS Institutional Class
         and for Benchmark Indices for Periods Ended December 31, 1999

<TABLE>
<CAPTION>
                                                           Since   Inception
                                 1 Year  3 Years 5 Years Inception   Date
- ----------------------------------------------------------------------------
<S>                              <C>     <C>     <C>     <C>       <C>
PIMCO Long-Term U.S. Government
 Fund/1/                         (7.99)   6.27    9.72     10.35    7/1/91
 Lehman Long-Term Treasury/2/    (8.74)   6.03    9.08
</TABLE>
- -------
/1/Prior to July 1997 and April 2000 the Long-Term U.S. Government Fund was
  managed by different portfolio managers.
/2/The Lehman Long-Term Treasury Index is an unmanaged index of U.S. Treasury
  issues with maturities greater than 10 years. It is not possible to invest
  directly in the index.

                                                                  Prospectus
                                                                              28
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

   PIMCO Variable Insurance Trust
A-1
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

                                                                  Prospectus
                                                                             A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

   PIMCO Variable Insurance Trust
A-3
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

                                                                  Prospectus
                                                                             A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust
            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington, D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.

[LOGO OF PIMCO FUNDS]

PIMCO Funds
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660


<PAGE>

[LOGO]            PIMCO Funds Prospectus

PIMCO             --------------------------------------------------------------
Variable          INTERMEDIATE DURATION BOND PORTFOLIO
Insurance         High Yield Bond Portfolio
Trust
                  --------------------------------------------------------------
April 1, 2000     STOCK PORTFOLIO
                  StocksPLUS Growth and Income Portfolio
Share Class

Adm Administrative

                  This cover is not part of the Prospectus


                                                           [LOGO OF PIMCO FUNDS]
<PAGE>

            Prospectus


PIMCO       This Prospectus describes the PIMCO High Yield Bond and StocksPLUS
Variable    Growth and Income Portfolios (the "Portfolios") which are separate
Insurance   investment portfolios offered by the PIMCO Variable Insurance
Trust       Trust (the "Trust"). The Portfolios provide access to the
            professional investment management services offered by Pacific
April 1,    Investment Management Company ("PIMCO"). The investments made by
2000        the Portfolios at any given time are not expected to be the same
            as those made by other mutual funds for which PIMCO acts as
Share       investment adviser, including mutual funds with investment
Class       objectives and strategies similar to those of the Portfolios.
            Accordingly, the performance of the Portfolios can be expected to
Admini-     vary from that of the other mutual funds.
strative
            This Prospectus explains what you should know about the Portfolios
            before you invest. Please read it carefully.

            Shares of the Portfolios currently are sold to segregated asset
            accounts ("Separate Accounts") of insurance companies that fund
            variable annuity contracts and variable life insurance policies
            ("Variable Contracts"). Assets in the Separate Account are
            invested in shares of the Portfolios in accordance with allocation
            instructions received from owners of the Variable Contracts
            ("Variable Contract Owners"). Variable Contract Owners do not deal
            directly with the Portfolios to purchase or redeem shares. The
            allocation rights of Variable Contract Owners are described in the
            accompanying Separate Account prospectus. Shares of the Portfolios
            also may be sold to qualified pension and retirement plans outside
            of the separate account context.

            This Prospectus should be read in conjunction with the prospectus
            of the Separate Account. Both prospectuses should be read
            carefully and retained for future reference.

            The Securities and Exchange Commission has not approved or
            disapproved these securities, or determined if this Prospectus is
            truthful or complete. Any representation to the contrary is a
            criminal offense.

   PIMCO Variable Insurance Trust
1
<PAGE>

            Table of Contents

<TABLE>
         <S>                                                               <C>
         Summary Information..............................................   3
         Portfolio Summaries..............................................   5
           High Yield Portfolio...........................................   5
           StocksPLUS Growth and Income Portfolio.........................   7
         Summary of Principal Risks.......................................   9
         Management of the Portfolios.....................................  12
         Investment Options...............................................  13
         Purchases and Redemptions........................................  14
         How Portfolio Shares are Priced..................................  15
         Tax Consequences.................................................  16
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  17
         Financial Highlights.............................................  27
         Appendix A--Description of Securities Ratings.................... A-1
</TABLE>

                                                                  Prospectus
                                                                               2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                                  Non-U.S.
                                                                                                  Dollar
                                                                                Credit            Denominated
                                            Main Investments          Duration  Quality(1)        Securities(2)
- ---------------------------------------------------------------------------------------------------------------
 <C>           <C>                          <S>                       <C>       <C>               <C>
 Intermediate  High Yield Bond              Higher yielding fixed     2-6 years B to Aaa; min 65%   0-15%(4)
 Duration                                   income securities                   below Baa
 Bond
 Portfolio
- ---------------------------------------------------------------------------------------------------------------
 Stock         StocksPLUS Growth and Income S&P 500 stock index       0-1 year  B to Aaa; max       0-20%(3)
 Portfolio                                  derivatives backed by a             10% below Baa
                                            portfolio of short-term
                                            fixed-income securities
- ---------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  Each Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.
(4)  The percentage limitation relates to euro-denominated securities.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)
Fixed       The High Yield Bond Portfolio is a "Fixed Income Portfolio". A
Income      Fixed Income Portfolio invests at least 65% of its assets in
Instruments "Fixed Income Instruments," which as used in this Prospectus
            includes:

            . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio   The Portfolios provide a broad range of investment choices. The
Descrip-    following summaries identify each Portfolio's investment
tions,      objective, principal investments and strategies, principal risks,
Perfor-     performance information and fees and expenses. A more detailed
mance       "Summary of Principal Risks" describing principal risks of
and Fees    investing in the Portfolios begins after the Portfolio Summaries.

             It is possible to lose money on investments in the Portfolios.

             An investment in a Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.

                                                                  Prospectus
                                                                               4
<PAGE>

            PIMCO High Yield Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Higher yielding      B to Aaa; minimum
and           Seeks maximum          fixed income         65% below Baa
Strategies    total return,          securities
              consistent with                             Dividend Frequency
              preservation of        Average Portfolio    Declared daily and
              capital and            Duration             distributed monthly
              prudent                2-6 years
              investment
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of high yield securities ("junk bonds")
            rated below investment grade but rated at least B by Moody's or
            S&P, or, if unrated, determined by PIMCO to be of comparable
            quality. The remainder of the Portfolio's assets may be invested
            in investment grade Fixed Income Instruments. The average
            portfolio duration of this Portfolio normally varies within a two-
            to six-year time frame based on PIMCO's forecast for interest
            rates. The Portfolio may invest without limit in U.S. dollar-
            denominated securities of foreign issuers. The Portfolio may
            invest up to 15% of its assets in euro-denominated securities. The
            Portfolio normally will hedge at least 75% of its exposure to the
            euro to reduce the risk of loss due to fluctuations in currency
            exchange rates.

             The Portfolio may invest up to 15% of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements. The Portfolio may invest all of its assets in
            mortgage- or asset-backed securities. The Portfolio may lend its
            portfolio securities to brokers, dealers, and other financial
            institutions to earn income. The Portfolio may seek to obtain
            market exposure to the securities in which it primarily invests by
            entering into a series of purchase and sale contracts or by using
            other investment techniques (such as buy backs or dollar rolls).
            The "total return" sought by the Portfolio consists of income
            earned on the Portfolio's investments, plus capital appreciation,
            if any, which generally arises from decreases in interest rates or
            improving credit fundamentals for a particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Issuer Risk         . Foreign
                 Risk                .  Liquidity Risk        Investment Risk
              .  Credit Risk         .  Derivatives Risk    . Currency Risk
              .  High Yield Risk     .  Mortgage Risk       . Leveraging Risk
              .  Market Risk                                . Management Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


5
   PIMCO Variable Insurance Trust
<PAGE>

            PIMCO High Yield Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

<TABLE>
<S>                                                        <C>

                                                           Highest and Lowest Quarter Returns
                                                           (for periods shown in the bar chart)
                                                           ------------------------------------
                                    [GRAPH]                Highest (1st Qtr.'99)          2.00%
                                                           ------------------------------------
                                 1999    3.01%             Lowest (2nd Qtr.'99)         (0.51%)
</TABLE>

                   Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                          1 Year (04/30/98)
            -----------------------------------------------
         <S>                              <C>    <C>
         Administrative Class             3.01%  2.88%
            -----------------------------------------------
         Lehman Brothers BB Intermediate
          Corporate Index(1)              2.20%  3.02%
            -----------------------------------------------
</TABLE>

            (1) The Lehman Brothers BB Intermediate Corporate Index is an
                unmanaged index comprised of various fixed income securities
                rated BB with an average duration of 4.40 years as of
                12/31/99. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.25%    0.15%   0.35%(1) 0.75%               0.00%        0.75%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.35% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.75% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $77                $240               $417               $930
            -----------------------------------------------------------------------------------
</TABLE>
                                                                               6
                                                                 Prospectus
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              S&P 500 stock        B to Aaa; maximum
and                                  index derivatives    10% below Baa
Strategies    Seeks total            backed by a
              return which           portfolio of         Dividend Frequency
              exceeds that of        short-term fixed     Declared and
              the S&P 500            income securities    distributed
                                                          quarterly
                                     Average Portfolio
                                     Duration
                                     0-1 year

            The Portfolio seeks to exceed the total return of the S&P 500 by
            investing under normal circumstances substantially all of its
            assets in S&P 500 derivatives, backed by a portfolio of Fixed
            Income Instruments. The Portfolio may invest in common stocks,
            options, futures, options on futures and swaps. The Portfolio uses
            S&P 500 derivatives in addition to or in place of S&P 500 stocks
            to attempt to equal or exceed the performance of the S&P 500. The
            value of S&P 500 derivatives closely track changes in the value of
            the index. However, S&P 500 derivatives may be purchased with a
            fraction of the assets that would be needed to purchase the equity
            securities directly, so that the remainder of the assets may be
            invested in Fixed Income Instruments. PIMCO actively manages the
            fixed income assets held by the Portfolio with a view toward
            enhancing the Portfolio's total return, subject to an overall
            portfolio duration which is normally not expected to exceed one
            year.

             The S&P 500 is composed of 500 selected common stocks that
            represent approximately two-thirds of the total market value of
            all U.S. common stocks. The Portfolio is neither sponsored by nor
            affiliated with S&P. The Portfolio seeks to remain invested in S&P
            500 derivatives or S&P 500 stocks even when the S&P 500 is
            declining.

             Though the Portfolio does not normally invest directly in S&P 500
            securities, when S&P 500 derivatives appear to be overvalued
            relative to the S&P 500, the Portfolio may invest all of its
            assets in a "basket" of S&P 500 stocks. Individual stocks are
            selected based on an analysis of the historical correlation
            between the return of every S&P 500 stock and the return on the
            S&P 500 itself. PIMCO may employ fundamental analysis of factors
            such as earnings and earnings growth, price to earnings ratio,
            dividend growth, and cash flows to choose among stocks that
            satisfy the correlation tests. Stocks chosen for the Portfolio are
            not limited to those with any particular weighting in the S&P 500.
            The Portfolio may also invest in exchange traded funds based on
            the S&P 500, such as Standard & Poor's Depositary Receipt.

             Assets not invested in equity securities or derivatives may be
            invested in Fixed Income Instruments. The Portfolio may invest up
            to 10% of its assets in high yield securities ("junk bonds") rated
            B or higher by Moody's or S&P, or, if unrated, determined by PIMCO
            to be of comparable quality. The Portfolio may invest up to 20% of
            its assets in securities denominated in foreign currencies and may
            invest beyond this limit in U.S. dollar denominated securities of
            foreign issuers. The Portfolio will normally hedge at least 75% of
            its exposure to foreign currency to reduce the risk of loss due to
            fluctuations in currency exchange rates. In addition, the
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income.

- --------------------------------------------------------------------------------
Principal   Under certain conditions, generally in a market where the value of
Risks       both S&P 500 derivatives and fixed income securities are
            declining, the Portfolio may experience greater losses than would
            be the case if it invested directly in a portfolio of S&P 500
            stocks. Among the principal risks of investing in the Portfolio,
            which could adversely affect its net asset value, yield and total
            return, are:

              . Market Risk          . Interest Rate Risk   . Mortgage Risk
              . Issuer Risk          . Liquidity Risk       . Leveraging Risk
              . Derivatives Risk     . Foreign Investment   . Management Risk
              . Credit Risk            Risk
                                     . Currency Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.


- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.

7  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

<TABLE>
<S>                                                         <C>
                                                            Highest and Lowest Quarter Returns
                                                            (for periods shown in the bar chart)
                                                            ------------------------------------
                                                            Highest (4th Qtr. '98)        21.95%
                                    [GRAPH]                 ------------------------------------
                                                            Lowest (3rd Qtr. '98)         -8.82%
                                1998     30.11%
                                1999     19.85%
</TABLE>

                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)
<TABLE>
<CAPTION>
                                                                                   Portfolio
                                                                                   Inception
                                              1 Year                               (12/31/97)
            ---------------------------------------------------------------------------------
         <S>                                  <C>                                  <C>
         Administrative Class                 19.85%                               24.87%
            ---------------------------------------------------------------------------------
         S&P 500 Index(1)                     21.04%                               24.75%
            ---------------------------------------------------------------------------------
</TABLE>

            (1) The Standard & Poor's 500 Composite Stock Price Index is an
                unmanaged index of common stocks. It is not possible to invest
                directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.40%    0.15%   0.10%(1) 0.65%               0.00%        0.65%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.10% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operation expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $208               $362               $810
            -----------------------------------------------------------------------------------
</TABLE>
                                                                               8
                                                                  Prospectus
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

High        Portfolios that invest in high yield securities and unrated
Yield       securities of similar credit quality (commonly known as "junk
Risk        bonds") may be subject to greater levels of interest rate, credit
            and liquidity risk than Portfolios that do not invest in such
            securities. High yield securities are considered predominately
            speculative with respect to the issuer's continuing ability to
            make principal and interest payments. An economic downturn or
            period of rising interest rates could adversely affect the market
            for high yield securities and reduce a Portfolio's ability to sell
            its high yield securities (liquidity risk).

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

   PIMCO Variable Insurance Trust
9
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolios may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    Portfolios that invest directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies are subject to the risk that those currencies
            will decline in value relative to the U.S. dollar, or, in the case
            of hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary

                                                                  Prospectus
                                                                              10
<PAGE>

            Fund, or by the imposition of currency controls or other political
            developments in the U.S. or abroad. As a result, a Portfolio's
            investments in foreign currency-denominated securities may reduce
            the returns of a Portfolio.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

   PIMCO Variable Insurance Trust
11
<PAGE>

            Management of the Portfolios

Investment  PIMCO serves as investment adviser and the administrator (serving
Adviser     in its capacity as administrator, the "Administrator") for the
and         Portfolios. Subject to the supervision of the Board of Trustees,
Admini-     PIMCO is responsible for managing the investment activities of the
strator     Portfolios and the Portfolios' business affairs and other
            administrative matters.

             PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
            Beach, California 92660. Organized in 1971, PIMCO provides
            investment management and advisory services to private accounts of
            institutional and individual clients and to mutual funds. As of
            December 31, 1999, PIMCO had approximately $186 billion in assets
            under management.

Advisory    Each Portfolio pays PIMCO fees in return for providing investment
Fees        advisory services. For the fiscal year ended December 31, 1999,
            the Portfolios paid monthly advisory fees to PIMCO at the
            following annual rates (stated as a percentage of the average
            daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio                               Advisory Fees
            --------------------------------------------------
         <S>                                     <C>
         High Yield Bond Portfolio                   0.50%
         StocksPLUS Growth and Income Portfolio      0.40%
</TABLE>

             Effective April 1, 2000, the Portfolios pay monthly advisory fees
            to PIMCO at the following annual rates (stated as a percentage of
            the average daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio
                                                 Advisory Fees
            --------------------------------------------------
         <S>                                     <C>
         High Yield Bond Portfolio                   0.25%
         StocksPLUS Growth and Income Portfolio      0.40%
</TABLE>

Administrative
Fees
            Each Portfolio pays for the administrative services it requires
            under a fee structure which is essentially fixed. Shareholders of
            each Portfolio pay an administrative fee to PIMCO, computed as a
            percentage of the Portfolio's assets attributable in the aggregate
            to that class of shares. PIMCO, in turn, provides or procures
            administrative services for shareholders and also bears the costs
            of various third-party services required by the Portfolios,
            including audit, custodial, portfolio accounting, legal, transfer
            agency and printing costs. The result of this fee structure is an
            expense level for shareholders of each Portfolio that, with
            limited exceptions, is precise and predictable under ordinary
            circumstances.

             For the fiscal year ended December 31, 1999, the Portfolios paid
            PIMCO monthly administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio       Administrative Fees
            --------------------------------
         <S>             <C>
         All Portfolios         0.25%
</TABLE>

             Effective April 1, 2000, the Portfolios pay PIMCO monthly
            administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio                             Administrative Fees
            ------------------------------------------------------
         <S>                                   <C>
         High Yield Bond Portfolio                    0.35%
         StocksPLUS Growth & Income Portfolio         0.10%
</TABLE>

                                                                  Prospectus
                                                                              12
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

<TABLE>
<CAPTION>
                                                      Recent Professional
         Portfolio          Portfolio Manager  Since  Experience
            -------------------------------------------------------------------

         <C>                <C>                <C>    <S>
         High Yield Bond    Benjamin L. Trosky  4/98* Managing Director, PIMCO.
                                                      He joined PIMCO as a
                                                      Portfolio Manager in
                                                      1990.

         StocksPLUS         William H. Gross   12/97* Managing Director, Chief
          Growth and Income                           Investment Officer and a
                                                      founding partner of
                                                      PIMCO. He leads a team
                                                      which manages the
                                                      StocksPLUS Portfolio.

</TABLE>

            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

   PIMCO Variable Insurance Trust
13
<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of each Portfolio. The Plan allows the
            Portfolios to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits a Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of a Portfolio's Administrative Class assets on
            an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account

                                                                  Prospectus
                                                                              14
<PAGE>

            allocating assets to the Portfolios are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolios might be
            required to redeem the investment of one or more of its separate
            accounts from the Portfolios, which might force the Portfolios to
            sell securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolios to dispose of
            their securities or to determine fairly the value of their net
            assets, or during any other period as permitted by the SEC for the
            protection of investors. In the event that a Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Administrative Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.


15 PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus
                                                                              16
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  Most of the Portfolios in this prospectus seek maximum total
Selection   return. The total return sought by a Portfolio consists of both
            income earned on a Portfolio's investments and capital
            appreciation, if any, arising from increases in the market value
            of a Portfolio's holdings. Capital appreciation of fixed income
            securities generally results from decreases in market interest
            rates or improving credit fundamentals for a particular market
            sector or security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of a Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio may invest all of its assets in mortgage- and
Related     asset-backed securities. Mortgage-related securities include
and Other   mortgage pass-through securities, collateralized mortgage
Asset-      obligations ("CMOs"), commercial mortgage-backed securities,
Backed      mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities  securities ("SMBSs") and other securities that directly or
            indirectly represent a participation in, or are secured by and
            payable from, mortgage loans on real property.

   PIMCO Variable Insurance Trust
17
<PAGE>

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolios may
            invest in other asset-backed securities that have been offered to
            investors.

Loan        Certain Portfolios may invest in fixed- and floating-rate loans,
Partici-    which investments generally will be in the form of loan
pations     participations and assignments of portions of such loans.
and         Participations and assignments involve special types of risk,
Assign-     including credit risk, interest rate risk, liquidity risk, and the
ments       risks of being a lender. If a Portfolio purchases a participation,
            it may only be able to enforce its rights through the lender, and
            may assume the credit risk of the lender in addition to the
            borrower.

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

                                                                  Prospectus
                                                                              18
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

            Variable and floating rate securities provide for a periodic
Variable    adjustment in the interest rate paid on the obligations. Each
and         Portfolio may invest in floating rate debt instruments
Floating    ("floaters") and engage in credit spread trades. While floaters
Rate        provide a certain degree of protection against rises in interest
Securities  rates, a Portfolio will participate in any declines in interest
            rates as well. Each Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. A Portfolio may not invest more than 5% of
            its assets in any combination of inverse floater, interest only,
            or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      Each Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

   PIMCO Variable Insurance Trust
19
<PAGE>

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

            Investing in the securities of issuers in any foreign country
Foreign     involves special risks and considerations not typically associated
(Non-       with investing in U.S. companies. Shareholders should consider
U.S.)       carefully the substantial risks involved for Portfolios that
Securities  invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             Certain Portfolios also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. Each Portfolio that may invest in
            foreign securities may invest up to 10% of its assets in
            securities of issuers based in countries with developing (or
            "emerging market") economies. Investing in emerging market
            securities imposes risks different from, or greater than, risks of
            investing in domestic securities or in foreign, developed
            countries. These risks include: smaller market capitalization of
            securities markets, which may suffer periods of relative
            illiquidity; significant price volatility; restrictions on foreign
            investment; possible repatriation of investment income and
            capital. In addition, foreign investors may be required to
            register the proceeds of sales; future economic or political
            crises could lead to price controls, forced mergers, expropriation
            or confiscatory taxation, seizure, nationalization, or creation of
            government monopolies. The currencies of emerging market countries
            may experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                Prospectus
                                                                              20
<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             Each Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolios' assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolios.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into
            forward foreign currency exchange contracts and invest in foreign
            currency futures contracts and options on foreign currencies and
            futures. A forward foreign currency exchange contract, which
            involves an obligation to purchase or sell a specific currency at
            a future date at a price set at the time of the contract, reduces
            a Portfolio's exposure to changes in the value of the currency it
            will deliver and increases its exposure
            to changes in the value of the currency it will receive for the
            duration of the contract. The effect on the value of a Portfolio
            is similar to selling securities denominated in one currency and
            purchasing securities denominated in another currency. A contract
            to sell foreign currency would limit any potential gain which
            might be realized if the value of the hedged currency increases. A
            Portfolio may enter into these contracts to hedge against foreign
            exchange risk, to increase exposure to a foreign currency or to
            shift exposure to foreign currency fluctuations from one currency
            to another. Suitable hedging transactions may not be available in
            all circumstances and there can be no assurance that a Portfolio
            will engage in such transactions at any given time or from time to
            time. Also, such transactions may not be successful and may
            eliminate any chance for a Portfolio to benefit from favorable
            fluctuations in relevant foreign currencies. A Portfolio may use
            one currency (or a basket of currencies) to hedge against adverse
            changes in the value of another currency (or a basket of
            currencies) when exchange rates between the two currencies are
            positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations
            under forward foreign currency exchange contracts entered into for
            non-hedging purposes.

Repurchase  Each Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


   PIMCO Variable Insurance Trust
21
<PAGE>

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. Each Portfolio may
            invest all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolios may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus
                                                                              22
<PAGE>

            each Portfolio will segregate assets determined to be liquid by
            PIMCO in accordance with procedures established by the Board of
            Trustees (or, as permitted by applicable regulation, enter into
            certain offsetting positions) to cover its obligations under
            derivative instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolios may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring a Portfolio to increase its investment in
Facilities  a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            a Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       Each Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Trans-      settlement date. This risk is in addition to the risk that the
actions     Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase a
            Portfolio's overall investment exposure. Typically, no income
            accrues on securities a Portfolio has committed to purchase prior
            to the time delivery of the securities is made, although a
            Portfolio may earn income on securities it has segregated to cover
            these positions.


   PIMCO Variable Insurance Trust
23
<PAGE>

Investment  Each Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, a Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, each
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       Each Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    Each Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.


                                                                   Prospectus
                                                                              24
<PAGE>

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

   PIMCO Variable Insurance Trust
25
<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                  Prospectus
                                                                              26
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
High Yield
 Administrative Class
 12/31/1999            $ 9.67     $0.77        $(0.49)(a)    $0.28       $(0.77)     $ 0.00         $0.00         $0.00
 12/31/1998(b)          10.00      0.51         (0.34)(a)     0.17        (0.50)       0.00          0.00          0.00
StocksPLUS Growth and Income
 Administrative Class
 12/31/1999            $12.58     $0.76        $ 1.65 (a)    $2.41       $(0.61)     $(0.82)        $0.00         $0.00
 12/31/1998(c)          10.00      0.30          2.68 (a)     2.98        (0.29)      (0.11)         0.00          0.00
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(b) Commenced operations on April 30, 1998.
(c) Commenced operations on December 31, 1997.

   PIMCO Variable Insurance Trust
27
<PAGE>




<TABLE>
<CAPTION>
                                                                   Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of    Investment
 Return                    Value               End     Expenses to  Income to   Portfolio
   of          Total        End    Total    of Period    Average     Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets   Net Assets    Rate
- -----------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>         <C>          <C>


  $0.00       $(0.77)     $ 9.18    3.01 %   $151,020     0.75%        8.25%        13%
   0.00        (0.50)       9.67    1.80       49,761     0.75         7.90*        13


  $0.00       $(1.43)     $13.56   19.85 %   $230,412     0.65%        5.69%        34%
   0.00        (0.40)      12.58   30.11       58,264     0.65         5.30         61
</TABLE>
- -------
*   Annualized.

                                                                  Prospectus
                                                                              28
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

   PIMCO Variable Insurance Trust
A-1
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings
& Poor's
Ratings     Investment Grade
Services
             AAA: Debt rated AAA has the highest rating assigned by Standard &
            Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

                                                                  Prospectus
                                                                             A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

   PIMCO Variable Insurance Trust
A-3
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

                                                                  Prospectus
                                                                             A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington, D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.


                             [LOGO OF PIMCO FUNDS]

PIMCO Funds

840 Newport Center Drive
Suite 300
Newport Beach, CA 92660


<PAGE>

[LOGO]              PIMCO Funds Prospectus

PIMCO               ------------------------------------------------------------
Variable            INTERMEDIATE DURATION BOND PORTFOLIOS
Insurance           Real Return Bond Portfolio
Trust               High Yield Bond Portfolio

April 1, 2000       ------------------------------------------------------------
                    STOCK PORTFOLIO
Share Class         StocksPLUS Growth and Income Portfolio

Adm Administrative  This cover is not part of the Prospectus

                                                           [LOGO OF PIMCO FUNDS]
<PAGE>

            Prospectus


PIMCO       This Prospectus describes 3 separate investment portfolios (the
Variable    "Portfolios"), offered by the PIMCO Variable Insurance Trust (the
Insurance   "Trust"). The Portfolios provide access to the professional
Trust       investment management services offered by Pacific Investment
            Management Company ("PIMCO"). The investments made by the
April 1,    Portfolios at any given time are not expected to be the same as
2000        those made by other mutual funds for which PIMCO acts as
            investment adviser, including mutual funds with investment
Share       objectives and strategies similar to those of the Portfolios.
Class       Accordingly, the performance of the Portfolios can be expected to
            vary from that of the other mutual funds.
Admini-
strative
            This Prospectus explains what you should know about the Portfolios
            before you invest. Please read it carefully.

            Shares of the Portfolios currently are sold to segregated asset
            accounts ("Separate Accounts") of insurance companies that fund
            variable annuity contracts and variable life insurance policies
            ("Variable Contracts"). Assets in the Separate Account are
            invested in shares of the Portfolios in accordance with allocation
            instructions received from owners of the Variable Contracts
            ("Variable Contract Owners"). Variable Contract Owners do not deal
            directly with the Portfolios to purchase or redeem shares. The
            allocation rights of Variable Contract Owners are described in the
            accompanying Separate Account prospectus. Shares of the Portfolios
            also may be sold to qualified pension and retirement plans outside
            of the separate account context.

            This Prospectus should be read in conjunction with the prospectus
            of the Separate Account. Both prospectuses should be read
            carefully and retained for future reference.

            The Securities and Exchange Commission has not approved or
            disapproved these securities, or determined if this Prospectus is
            truthful or complete. Any representation to the contrary is a
            criminal offense.

   PIMCO Variable Insurance Trust
1
<PAGE>

            Table of Contents

<TABLE>
         <S>                                                               <C>
         Summary Information..............................................   3
           Real Return Bond Portfolio.....................................   5
           High Yield Bond Portfolio......................................   7
           StocksPLUS Growth and Income Portfolio.........................   9
         Summary of Principal Risks.......................................  11
         Management of the Portfolios.....................................  14
         Investment Options...............................................  15
         Purchases and Redemptions........................................  16
         How Portfolio Shares are Priced..................................  17
         Tax Consequences.................................................  18
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  19
         Financial Highlights.............................................  29
         Other Information................................................  31
         Appendix A--Description of Securities Ratings.................... A-1
</TABLE>

                                                                  Prospectus
                                                                               2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                                  Non-U.S.
                                                                                                  Dollar
                                                                                Credit            Denominated
                                            Main Investments          Duration  Quality(1)        Securities(2)
- ---------------------------------------------------------------------------------------------------------------
 <C>           <C>                          <S>                       <C>       <C>               <C>
 Intermediate  Real Return Bond             Inflation-indexed fixed   N/A       B to Aaa; max 10%   0-20%(3)
 Duration                                   income securities                   below Baa
 Bond
 Portfolios
         ------------------------------------------------------------------------------------------------------
               High Yield Bond              Higher yielding fixed     2-6 years B to Aaa; min 65%   0-15%(4)
                                            income securities                   below Baa
- ---------------------------------------------------------------------------------------------------------------
 Stock         StocksPLUS Growth and Income S&P 500 stock index       0-1 year  B to Aaa; max       0-20%(3)
 Portfolio                                  derivatives backed by a             10% below Baa
                                            portfolio of
                                            short-term fixed-income
                                            securities
- ---------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  Each Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.
(4)  The percentage limitation relates to euro-denominated securities.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)

Fixed       The "Fixed Income Portfolios" are the Real Return Bond, and the
Income      High Yield Bond Portfolios. Each of the Fixed Income Portfolios
Instruments differs from the other primarily in the length of the Portfolio's
            duration or the proportion of its investments in certain types of
            fixed income securities. Each Fixed Income Portfolio invests at
            least 65% of its assets in "Fixed Income Instruments," which as
            used in this Prospectus includes:

            . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio   The Portfolios provide a broad range of investment choices. The
Descrip-    following summaries identify each Portfolio's investment
tions,      objective, principal investments and strategies, principal risks,
Performance performance information and fees and expenses. A more detailed
and Fees    "Summary of Principal Risks" describing principal risks of
            investing in the Portfolios begins after the Portfolio Summaries.

             It is possible to lose money on investments in the Portfolios.

             An investment in a Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.


                                                                  Prospectus
                                                                               4
<PAGE>

            PIMCO Real Return Bond Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Inflation indexed    B to Aaa; maximum
and                                  fixed income         10% below Baa
Strategies                           securities
              Seeks maximum                               Dividend
              real return,                                Frequency
              consistent with                             Declared daily and
              preservation of        Average Portfolio    distributed monthly
              real capital and       Duration
              prudent                See description
              investment             below
              management

            The Portfolio seeks its investment objective by investing under
            normal circumstances at least 65% of its assets in inflation-
            indexed bonds of varying maturities issued by the U.S. and non-
            U.S. governments, their agencies or government-sponsored
            enterprises and corporations. Inflation-indexed bonds are fixed
            income securities that are structured to provide protection
            against inflation. The value of the bond's principal or the
            interest income paid on the bond is adjusted to track changes in
            an official inflation measure. The U.S. Treasury uses the Consumer
            Price Index for Urban Consumers as the inflation measure.
            Inflation-indexed bonds issued by a foreign government are
            generally adjusted to reflect a comparable inflation index,
            calculated by that government. "Real return" equals total return
            less the estimated cost of inflation, which is typically measured
            by the change in an official inflation measure.

             Because of the unique features of inflation-indexed bonds, PIMCO
            uses a modified form of duration for the Portfolio ("real
            duration") which measures price changes as a result of changes in
            "real" interest rates. A "real" interest rate is the market
            interest rate minus expected inflation. There is no limit on the
            real duration of the Portfolio, but it is expected that the
            average real duration of this Portfolio will normally vary
            approximately within the range of the average real duration of all
            inflation-indexed bonds issued by the U.S. Treasury in the
            aggregate, which as of March 7, 2000 was 9.0 years. For point of
            reference, it is expected that the average portfolio duration (as
            opposed to real duration) of the Portfolio will generally vary
            within a one- to five-year time frame, although this range is
            subject to change.

             The Portfolio invests primarily in investment grade securities,
            but may invest up to 10% of its assets in high yield securities
            ("junk bonds") rated B or higher by Moody's or S&P, or, if
            unrated, determined by PIMCO to be of comparable quality. The
            Portfolio also may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates. The Portfolio is non-diversified, which
            means that it may concentrate its assets in a smaller number of
            issuers than a diversified Portfolio.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls).

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              . Interest Rate Risk   . Derivatives Risk     . Currency Risk
              . Credit Risk          . Liquidity Risk       . Leveraging Risk
              . Market Risk          . Issuer Non-          . Management Risk
              . Issuer Risk             Diversification Risk
                                     . Foreign Investment Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.

5  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Real Return Bond Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual
                                                   Portfolio                 Net Portfolio
                         Advisory Service Other    Operating    Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses     Reduction(2) Expenses
            ------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>          <C>          <C>
         Administrative  0.25%    0.15%   0.52%(1) 0.92%        (0.27%)      0.65%
            ------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.27%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class                         Year 1                                         Year 3
            --------------------------------------------------------------------------------------
         <S>                                 <C>                                            <C>
         Administrative                      $66                                            $266
            --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>

            PIMCO High Yield Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Higher yielding      B to Aaa; minimum
and           Seeks maximum          fixed income         65% below Baa
Strategies    total return,          securities
              consistent with                             Dividend Frequency
              preservation of        Average Portfolio    Declared daily and
              capital and            Duration             distributed monthly
              prudent                2-6 years
              investment
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of high yield securities ("junk bonds")
            rated below investment grade but rated at least B by Moody's or
            S&P, or, if unrated, determined by PIMCO to be of comparable
            quality. The remainder of the Portfolio's assets may be invested
            in investment grade Fixed Income Instruments. The average
            portfolio duration of this Portfolio normally varies within a two-
            to six-year time frame based on PIMCO's forecast for interest
            rates. The Portfolio may invest without limit in U.S. dollar-
            denominated securities of foreign issuers. The Portfolio may
            invest up to 15% of its assets in euro-denominated securities. The
            Portfolio normally will hedge at least 75% of its exposure to the
            euro to reduce the risk of loss due to fluctuations in currency
            exchange rates.

             The Portfolio may invest up to 15% of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements. The Portfolio may invest all of its assets in
            mortgage- or asset-backed securities. The Portfolio may lend its
            portfolio securities to brokers, dealers, and other financial
            institutions to earn income. The Portfolio may seek to obtain
            market exposure to the securities in which it primarily invests by
            entering into a series of purchase and sale contracts or by using
            other investment techniques (such as buy backs or dollar rolls).
            The "total return" sought by the Portfolio consists of income
            earned on the Portfolio's investments, plus capital appreciation,
            if any, which generally arises from decreases in interest rates or
            improving credit fundamentals for a particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Issuer Risk         . Foreign
                 Risk                .  Liquidity Risk       Investment Risk
              .  Credit Risk         .  Derivatives Risk    .  Currency Risk
              .  High Yield Risk     .  Mortgage Risk       .  Leveraging Risk
              .  Market Risk                                .  Management Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


7
   PIMCO Variable Insurance Trust
<PAGE>

            PIMCO High Yield Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class



                                    [GRAPH]

                                 1999     3.01%

                   Calendar Year End (through 12/31)

 Highest and Lowest Quarter Returns
 (for periods shown in the bar chart
 -----------------------------------
 Highest (1st Qtr.'99)         2.00%
 -----------------------------------
 Lowest (2nd Qtr. '99)       (0.51%)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                          1 Year (04/30/98)
         --------------------------------------------------
         <S>                              <C>    <C>
         Administrative Class             3.01%  2.88%
         --------------------------------------------------
         Lehman Brothers BB Intermediate
          Corporate Index(1)              2.20%  3.02%
         --------------------------------------------------
</TABLE>

            (1) The Lehman Brothers BB Intermediate Corporate Index is an
                unmanaged index comprised of various fixed income securities
                rated BB with an average duration of 4.40 years as of
                12/31/99. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
         ----------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.25%    0.15%   0.35%(1) 0.75%               0.00%        0.75%
         ----------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.35% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.75% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
         --------------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $77                $240               $417               $930
         --------------------------------------------------------------------------------------
</TABLE>

                                                                 Prospectus    8
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              S&P 500 stock        B to Aaa; maximum
and                                  index derivatives    10% below Baa
Strategies    Seeks total            backed by a
              return which           portfolio of         Dividend
              exceeds that of        short-term fixed     Frequency
              the S&P 500            income securities    Declared and
                                                          distributed
                                     Average Portfolio    quarterly
                                     Duration
                                     0-1 year

            The Portfolio seeks to exceed the total return of the S&P 500 by
            investing under normal circumstances substantially all of its
            assets in S&P 500 derivatives, backed by a portfolio of Fixed
            Income Instruments. The Portfolio may invest in common stocks,
            options, futures, options on futures and swaps. The Portfolio uses
            S&P 500 derivatives in addition to or in place of S&P 500 stocks
            to attempt to equal or exceed the performance of the S&P 500. The
            value of S&P 500 derivatives closely track changes in the value of
            the index. However, S&P 500 derivatives may be purchased with a
            fraction of the assets that would be needed to purchase the equity
            securities directly, so that the remainder of the assets may be
            invested in Fixed Income Instruments. PIMCO actively manages the
            fixed income assets held by the Portfolio with a view toward
            enhancing the Portfolio's total return, subject to an overall
            portfolio duration which is normally not expected to exceed one
            year.

             The S&P 500 is composed of 500 selected common stocks that
            represent approximately two-thirds of the total market value of
            all U.S. common stocks. The Portfolio is neither sponsored by nor
            affiliated with S&P. The Portfolio seeks to remain invested in S&P
            500 derivatives or S&P 500 stocks even when the S&P 500 is
            declining.

             Though the Portfolio does not normally invest directly in S&P 500
            securities, when S&P 500 derivatives appear to be overvalued
            relative to the S&P 500, the Portfolio may invest all of its
            assets in a "basket" of S&P 500 stocks. Individual stocks are
            selected based on an analysis of the historical correlation
            between the return of every S&P 500 stock and the return on the
            S&P 500 itself. PIMCO may employ fundamental analysis of factors
            such as earnings and earnings growth, price to earnings ratio,
            dividend growth, and cash flows to choose among stocks that
            satisfy the correlation tests. Stocks chosen for the Portfolio are
            not limited to those with any particular weighting in the S&P 500.
            The Portfolio may also invest in exchange traded funds based on
            the S&P 500, such as Standard & Poor's Depositary Receipt.

             Assets not invested in equity securities or derivatives may be
            invested in Fixed Income Instruments. The Portfolio may invest up
            to 10% of its assets in high yield securities ("junk bonds") rated
            B or higher by Moody's or S&P, or, if unrated, determined by PIMCO
            to be of comparable quality. The Portfolio may invest up to 20% of
            its assets in securities denominated in foreign currencies and may
            invest beyond this limit in U.S. dollar denominated securities of
            foreign issuers. The Portfolio will normally hedge at least 75% of
            its exposure to foreign currency to reduce the risk of loss due to
            fluctuations in currency exchange rates. In addition, the
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income.

- --------------------------------------------------------------------------------
Principal   Under certain conditions, generally in a market where the value of
Risks       both S&P 500 derivatives and fixed income securities are
            declining, the Portfolio may experience greater losses than would
            be the case if it invested directly in a portfolio of S&P 500
            stocks. Among the principal risks of investing in the Portfolio,
            which could adversely affect its net asset value, yield and total
            return, are:

              . Market Risk          . Interest Rate        . Mortgage Risk
              . Issuer Risk             Risk                . Leveraging Risk
              . Derivatives Risk     . Liquidity Risk       . Management Risk
              . Credit Risk          . Foreign
                                        Investment
                                        Risk
                                     . Currency Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.
- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.

9  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class




                                  [GRAPH]

                              1998     30.11%
                              1999     19.85%

                  Calendar Year End (through 12/31)

Highest and Lowest Quarter Returns
(for periods shown in the bar chart)
- ------------------------------------
Highest (4th Qtr. '98)        21.95%
- ------------------------------------
Lowest (3rd Qtr. '98)         -8.82%

            Average Annual Total Returns (for periods ended 12/31/99)
<TABLE>
<CAPTION>
                                                                                   Portfolio
                                                                                   Inception
                                              1 Year                               (12/31/97)
         ------------------------------------------------------------------------------------
         <S>                                  <C>                                  <C>
         Administrative Class                 19.85%                               24.87%
         ------------------------------------------------------------------------------------
         S&P 500 Index(1)                     21.04%                               24.75%
         ------------------------------------------------------------------------------------
</TABLE>

            (1) The Standard & Poor's 500 Composite Stock Price Index is an
                unmanaged index of common stocks. It is not possible to invest
                directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
         ----------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.40%    0.15%   0.10%(1) 0.65%               0.00%        0.65%
         ----------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.10% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operation expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
         --------------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $208               $362               $810
         --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus  10
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

High        Portfolios that invest in high yield securities and unrated
Yield       securities of similar credit quality (commonly known as "junk
Risk        bonds") may be subject to greater levels of interest rate, credit
            and liquidity risk than Portfolios that do not invest in such
            securities. High yield securities are considered predominately
            speculative with respect to the issuer's continuing ability to
            make principal and interest payments. An economic downturn or
            period of rising interest rates could adversely affect the market
            for high yield securities and reduce a Portfolio's ability to sell
            its high yield securities (liquidity risk).

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

   PIMCO Variable Insurance Trust
11
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolios may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    Portfolios that invest directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies are subject to the risk that those currencies
            will decline in value relative to the U.S. dollar, or, in the case
            of hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary

                                                                  Prospectus
                                                                              12
<PAGE>

            Fund, or by the imposition of currency controls or other political
            developments in the U.S. or abroad. As a result, a Portfolio's
            investments in foreign currency-denominated securities may reduce
            the returns of a Portfolio.

Issuer      Focusing investments in a small number of issuers, industries or
Non-        foreign currencies increases risk. Portfolios that are "non-
Diversi-    diversified" may invest a greater percentage of their assets in
fication    the securities of a single issuer (such as bonds issued by a
Risk        particular state) than Portfolios that are "diversified."
            Portfolios that invest in a relatively small number of issuers are
            more susceptible to risks associated with a single economic,
            political or regulatory occurrence than a more diversified
            portfolio might be. Some of those issuers also may present
            substantial credit or other risks. Similarly, a Portfolio may be
            more sensitive to adverse economic, business or political
            developments if it invests a substantial portion of its assets in
            the bonds of similar projects or from issuers in the same state.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

   PIMCO Variable Insurance Trust
13
<PAGE>

            Management of the Portfolios

Investment  PIMCO serves as investment adviser and the administrator (serving
Adviser     in its capacity as administrator, the "Administrator") for the
and         Portfolios. Subject to the supervision of the Board of Trustees,
Admini-     PIMCO is responsible for managing the investment activities of the
strator     Portfolios and the Portfolios' business affairs and other
            administrative matters.

             PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
            Beach, California 92660. Organized in 1971, PIMCO provides
            investment management and advisory services to private accounts of
            institutional and individual clients and to mutual funds. As of
            December 31, 1999, PIMCO had approximately $186 billion in assets
            under management.

Advisory    Each Portfolio pays PIMCO fees in return for providing investment
Fees        advisory services. For the fiscal year ended December 31, 1999,
            the Portfolios paid monthly advisory fees to PIMCO at the
            following annual rates (stated as a percentage of the average
            daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
            Portfolio                  Advisory Fees
            ----------------------------------------
            <S>                        <C>
            High Yield Bond Portfolio      0.50%
            All other Portfolios           0.40%
</TABLE>

             Effective April 1, 2000, the Portfolios pay monthly advisory fees
            to PIMCO at the following annual rates (stated as a percentage of
            the average daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
            Portfolio
                                                 Advisory Fees
            --------------------------------------------------
            <S>                                     <C>
            StocksPLUS Growth and Income Portfolio      0.40%
            All other Portfolios                        0.25%
</TABLE>

Admini-     Each Portfolio pays for the administrative services it requires
strative    under a fee structure which is essentially fixed. Shareholders of
Fees        each Portfolio pay an administrative fee to PIMCO, computed as a
            percentage of the Portfolio's assets attributable in the aggregate
            to that class of shares. PIMCO, in turn, provides or procures
            administrative services for shareholders and also bears the costs
            of various third-party services required by the Portfolios,
            including audit, custodial, portfolio accounting, legal, transfer
            agency and printing costs. The result of this fee structure is an
            expense level for shareholders of each Portfolio that, with
            limited exceptions, is precise and predictable under ordinary
            circumstances.

             For the fiscal year ended December 31, 1999, the Portfolios paid
            PIMCO monthly administrative fees at the following annual rates:

<TABLE>
<CAPTION>
            Portfolio       Administrative Fees
            --------------------------------
            <S>             <C>
            All Portfolios         0.25%
</TABLE>

             Effective April 1, 2000, the Portfolios pay PIMCO monthly
            administrative fees at the following annual rates:

<TABLE>
<CAPTION>
            Portfolio                             Administrative Fees
            ------------------------------------------------------
            <S>                                   <C>
            StocksPLUS Growth & Income Portfolio         0.10%
            High Yield Bond Portfolio                    0.35%
            Real Return Bond Portfolio                   0.25%
</TABLE>

                                                                  Prospectus
                                                                              14
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

<TABLE>
<CAPTION>
                                                        Recent Professional
         Portfolio          Portfolio Manager    Since  Experience
            --------------------------------------------------------------------
         <C>                <C>                  <C>    <S>
         StocksPLUS         William H. Gross     12/97* Managing Director, Chief
          Growth and Income                             Investment Officer and a
                                                        founding partner of
                                                        PIMCO. He leads a team
                                                        which manages the
                                                        StocksPLUS Portfolio.

         Real Return Bond   John B. Brynjolfsson  9/99* Executive Vice
                                                        President, PIMCO. He
                                                        joined PIMCO as a
                                                        Portfolio Manager in
                                                        1989, and has managed
                                                        fixed income accounts
                                                        for various
                                                        institutional clients
                                                        and funds since that
                                                        time.

         High Yield Bond    Benjamin L. Trosky    4/98* Managing Director,
                                                        PIMCO. He joined PIMCO
                                                        as a Portfolio Manager
                                                        in 1990.
</TABLE>
            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

   PIMCO Variable Insurance Trust
15
<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of each Portfolio. The Plan allows the
            Portfolios to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits a Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of a Portfolio's Administrative Class assets on
            an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account

                                                                  Prospectus
                                                                              16
<PAGE>

            allocating assets to the Portfolios are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolios might be
            required to redeem the investment of one or more of its separate
            accounts from the Portfolios, which might force the Portfolios to
            sell securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolios to dispose of
            their securities or to determine fairly the value of their net
            assets, or during any other period as permitted by the SEC for the
            protection of investors. In the event that a Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Administrative Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.


17 PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.
            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus
                                                                              18
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  Most of the Portfolios in this prospectus seek maximum total
Selection   return. The total return sought by a Portfolio consists of both
            income earned on a Portfolio's investments and capital
            appreciation, if any, arising from increases in the market value
            of a Portfolio's holdings. Capital appreciation of fixed income
            securities generally results from decreases in market interest
            rates or improving credit fundamentals for a particular market
            sector or security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of a Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio may invest all of its assets in mortgage- and
Related     asset-backed securities. Mortgage-related securities include
and Other   mortgage pass-through securities, collateralized mortgage
Asset-      obligations ("CMOs"), commercial mortgage-backed securities,
Backed      mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities  securities ("SMBSs") and other securities that directly or
            indirectly represent a participation in, or are secured by and
            payable from, mortgage loans on real property.

   PIMCO Variable Insurance Trust
19
<PAGE>

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolios may
            invest in other asset-backed securities that have been offered to
            investors.

Loan        Certain Portfolios may invest in fixed- and floating-rate loans,
Partici-    which investments generally will be in the form of loan
pations     participations and assignments of portions of such loans.
and         Participations and assignments involve special types of risk,
Assign-     including credit risk, interest rate risk, liquidity risk, and the
ments       risks of being a lender. If a Portfolio purchases a participation,
            it may only be able to enforce its rights through the lender, and
            may assume the credit risk of the lender in addition to the
            borrower.

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

                                                                  Prospectus
                                                                              20
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

Variable    Variable and floating rate securities provide for a periodic
and         adjustment in the interest rate paid on the obligations. Each
Floating    Portfolio may invest in floating rate debt instruments
Rate        ("floaters") and engage in credit spread trades. While floaters
Securities  provide a certain degree of protection against rises in interest
            rates, a Portfolio will participate in any declines in interest
            rates as well. Each Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. A Portfolio may not invest more than 5% of
            its assets in any combination of inverse floater, interest only,
            or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      Each Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

   PIMCO Variable Insurance Trust
21
<PAGE>

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Foreign     Investing in the securities of issuers in any foreign country
(Non-       involves special risks and considerations not typically associated
U.S.)       with investing in U.S. companies. Shareholders should consider
Securities  carefully the substantial risks involved for Portfolios that
            invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             Certain Portfolios also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. Each Portfolio that may invest in
            foreign securities may invest up to 10% of it assets in securities
            of issuers based in countries with developing (or "emerging
            market") economies. Investing in emerging market securities
            imposes risks different from, or greater than, risks of investing
            in domestic securities or in foreign, developed countries. These
            risks include: smaller market capitalization of securities
            markets, which may suffer periods of relative illiquidity;
            significant price volatility; restrictions on foreign investment;
            possible repatriation of investment income and capital. In
            addition, foreign investors may be required to register the
            proceeds of sales; future economic or political crises could lead
            to price controls, forced mergers, expropriation or confiscatory
            taxation, seizure, nationalization, or creation of government
            monopolies. The currencies of emerging market countries may
            experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                Prospectus
                                                                              22
<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             Each Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolios' assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolios.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into
            forward foreign currency exchange contracts and invest in foreign
            currency futures contracts and options on foreign currencies and
            futures. A forward foreign currency exchange contract, which
            involves an obligation to purchase or sell a specific currency at
            a future date at a price set at the time of the contract, reduces
            a Portfolio's exposure to changes in the value of the currency it
            will deliver and increases its exposure
            to changes in the value of the currency it will receive for the
            duration of the contract. The effect on the value of a Portfolio
            is similar to selling securities denominated in one currency and
            purchasing securities denominated in another currency. A contract
            to sell foreign currency would limit any potential gain which
            might be realized if the value of the hedged currency increases. A
            Portfolio may enter into these contracts to hedge against foreign
            exchange risk, to increase exposure to a foreign currency or to
            shift exposure to foreign currency fluctuations from one currency
            to another. Suitable hedging transactions may not be available in
            all circumstances and there can be no assurance that a Portfolio
            will engage in such transactions at any given time or from time to
            time. Also, such transactions may not be successful and may
            eliminate any chance for a Portfolio to benefit from favorable
            fluctuations in relevant foreign currencies. A Portfolio may use
            one currency (or a basket of currencies) to hedge against adverse
            changes in the value of another currency (or a basket of
            currencies) when exchange rates between the two currencies are
            positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations
            under forward foreign currency exchange contracts entered into for
            non-hedging purposes.

Repurchase  Each Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


   PIMCO Variable Insurance Trust
23
<PAGE>

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. Each Portfolio may
            invest all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolios may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus
                                                                              24
<PAGE>

            each Portfolio will segregate assets determined to be liquid by
            PIMCO in accordance with procedures established by the Board of
            Trustees (or, as permitted by applicable regulation, enter into
            certain offsetting positions) to cover its obligations under
            derivative instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolios may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring a Portfolio to increase its investment in
Facilities  a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            a Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       Each Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Transactionssettlement date. This risk is in addition to the risk that the
            Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase a
            Portfolio's overall investment exposure. Typically, no income
            accrues on securities a Portfolio has committed to purchase prior
            to the time delivery of the securities is made, although a
            Portfolio may earn income on securities it has segregated to cover
            these positions.


   PIMCO Variable Insurance Trust
25
<PAGE>

Investment  Each Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, a Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, each
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       Each Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    Each Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.


                                                                  Prospectus
                                                                              26
<PAGE>

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

   PIMCO Variable Insurance Trust
27
<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                  Prospectus
                                                                              28
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(b)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Real Return
 Administrative Class
 12/31/1999(a)         $10.00     $0.20        $(0.20)(b)    $0.00       $(0.20)     $ 0.00         $0.00         $0.00
High Yield
 Administrative Class
 12/31/1999            $ 9.67     $0.77        $(0.49)(b)    $0.28       $(0.77)     $ 0.00         $0.00         $0.00
 12/31/1998(d)          10.00      0.51         (0.34)(b)     0.17        (0.50)       0.00          0.00          0.00
StocksPLUS Growth and Income
 Administrative Class
 12/31/1999            $12.58     $0.76        $ 1.65 (b)    $2.41       $(0.61)     $(0.82)        $0.00         $0.00
 12/31/1998(e)          10.00      0.30          2.68 (b)     2.98        (0.29)      (0.11)         0.00          0.00
</TABLE>
- -------
(a) Commenced operations on September 30, 1999.
(b) Per share amounts based on average number of shares outstanding during the
    period.
(d) Commenced operations on April 30, 1998.
(e) Commercial operations on December 31, 1997.

   PIMCO Variable Insurance Trust
29
<PAGE>




<TABLE>
<CAPTION>
                                                                     Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of      Investment
 Return                    Value               End     Expenses to    Income to   Portfolio
   of          Total        End    Total    of Period    Average       Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets     Net Assets    Rate
- -------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>           <C>          <C>


  $0.00       $(0.20)     $ 9.80   (0.03)%   $  3,000     0.65%*(c)      7.72%*       23%


  $0.00       $(0.77)     $ 9.18    3.01 %   $151,020     0.75%          8.25%        13%
   0.00        (0.50)       9.67    1.80       49,761     0.75           7.90*        13


  $0.00       $(1.43)     $13.56   19.85 %   $230,412     0.65%          5.69%        34%
   0.00        (0.40)      12.58   30.11       58,264     0.65           5.30         61
</TABLE>
- -------
*   Annualized.
(c) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.92%* for the
    period ended December 31, 1999.

                                                                  Prospectus
                                                                              30
<PAGE>

            Other Information


Performance The following table provides information concerning the historical
Information total return performance of the Institutional Class shares of one
of          series of PIMCO Funds: Pacific Investment Management Series
Similar     ("PIMS"). The PIMS series has investment objectives, policies and
Funds       strategies substantially similar to those of its respective PIMCO
            Variable Insurance Trust ("PVIT") Portfolio and is currently
            managed by the same portfolio manager. While the investment
            objectives and policies of the PIMS series and its respective PVIT
            Portfolio are similar, they are not identical and the performance
            of the PIMS series and the PVIT Portfolio will vary. The data is
            provided to illustrate the past performance of PIMCO in managing a
            substantially similar investment portfolio and does not represent
            the past performance of the PVIT Portfolio or the future
            performance of the PVIT Portfolio or its portfolio manager.
            Consequently, potential investors should not consider this
            performance data as an indication of the future performance of the
            PVIT Portfolio or of its portfolio manager.

            The performance data shown below reflects the operating expenses
            of the Institutional Class of the PIMS series. The operating
            expenses of the Institutional Class of the PIMS series in the
            table are lower than the operating expenses of the Administrative
            Class of the corresponding PVIT Portfolio. As such, performance
            would have been lower if the PVIT Portfolio's expenses were used.
            In addition, the PIMS series, unlike the Portfolios, are not sold
            to Separate Accounts to fund Variable Contracts. As a result, the
            performance results presented below do not take into account
            charges or deductions against a Separate Account or Variable
            Contract for cost of insurance charges, premium loads,
            administrative fees, maintenance fees, premium taxes, mortality
            and expense risk charges, or other charges that may be incurred
            under a Variable Contract for which the Portfolio serves as an
            underlying investment vehicle. By contrast, Variable Contract
            Owners with contract value allocated to the Portfolios will be
            subject to charges and expenses relating to the Variable Contracts
            and Separate Accounts.

            The PIMS series' performance data shown below is calculated in
            accordance with standards prescribed by the SEC for the
            calculation of average annual total return information. The
            investment results of the PIMS series presented below are
            unaudited and are not intended to predict or suggest results that
            might be experienced by the PIMS series or the Portfolio. Share
            prices and investment returns will fluctuate reflecting market
            conditions, as well as changes in company-specific fundamentals of
            portfolio securities. The performance data for the benchmark index
            identified below does not reflect the fees or expenses of the PIMS
            series or the Portfolio.

   Average Annual Total Return for Similar Series of PIMS Institutional Class
         and for Benchmark Indices for Periods Ended December 31, 1999

<TABLE>
<CAPTION>
                                                              Since   Inception
                                     1 Year 3 Years 5 Years Inception   Date
- -------------------------------------------------------------------------------
<S>                                  <C>    <C>     <C>     <C>       <C>
PIMCO Real Return Bond Fund           5.72    N/A     N/A     5.13     1/29/97
 Lehman Inflation Linked Treasury/1/  2.36    N/A     N/A
</TABLE>
- -------
/1/The Lehman Brothers Inflation Linked Treasury Index is an unmanaged market
  index consisting of the U.S. Treasury Inflation Protected Securities market.
  It is not possible to invest directly in the index.

   PIMCO Variable Insurance Trust
31
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

                                                                  Prospectus
                                                                             A-1
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.


   PIMCO Variable Insurance Trust
A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

                                                                  Prospectus
                                                                             A-3
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

   PIMCO Variable Insurance Trust
A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington, D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.


                             [LOGO OF PIMCO FUNDS]

PIMCO Funds

840 Newport Center Drive
Suite 300
Newport Beach, CA 92660



<PAGE>


[LOGO]              PIMCO Funds Prospectus

PIMCO               ------------------------------------------------------------
Variable            INTERMEDIATE DURATION BOND PORTFOLIOS
Insurance           Total Return Bond Portfolio
Trust               High Yield Bond Portfolio

April 1, 2000

Share Class

Adm Administrative  This cover is not part of the Prospectus

                                                           [LOGO OF PIMCO FUNDS]

<PAGE>

            Prospectus


PIMCO       This Prospectus describes the Total Return Bond and High Yield
Variable    Bond Portfolios (the "Portfolios") which are separate investment
Insurance   portfolios offered by the PIMCO Variable Insurance Trust (the
Trust       "Trust"). The Portfolios provide access to the professional
            investment management services offered by Pacific Investment
April 1,    Management Company ("PIMCO"). The investments made by the
2000        Portfolios at any given time are not expected to be the same as
            those made by other mutual funds for which PIMCO acts as
Share       investment adviser, including mutual funds with investment
Class       objectives and strategies similar to those of the Portfolios.
Adminis-    Accordingly, the performance of the Portfolios can be expected to
trative     vary from that of the other mutual funds.

            This Prospectus explains what you should know about the Portfolios
            before you invest. Please read it carefully.

            Shares of the Portfolios currently are sold to segregated asset
            accounts ("Separate Accounts") of insurance companies that fund
            variable annuity contracts and variable life insurance policies
            ("Variable Contracts"). Assets in the Separate Account are
            invested in shares of the Portfolios in accordance with allocation
            instructions received from owners of the Variable Contracts
            ("Variable Contract Owners"). Variable Contract Owners do not deal
            directly with the Portfolios to purchase or redeem shares. The
            allocation rights of Variable Contract Owners are described in the
            accompanying Separate Account prospectus. Shares of the Portfolios
            also may be sold to qualified pension and retirement plans outside
            of the separate account context.

            This Prospectus should be read in conjunction with the prospectus
            of the Separate Account. Both prospectuses should be read
            carefully and retained for future reference.

            The Securities and Exchange Commission has not approved or
            disapproved these securities, or determined if this Prospectus is
            truthful or complete. Any representation to the contrary is a
            criminal offense.

   PIMCO Variable Insurance Trust
1
<PAGE>

            Table of Contents

<TABLE>
         <S>                                                               <C>
         Summary Information..............................................   3
         Portfolio Summaries..............................................   5
           Total Return Bond Portfolio....................................   5
           High Yield Bond Portfolio......................................   7
         Summary of Principal Risks.......................................   9
         Management of the Portfolios.....................................  12
         Investment Options...............................................  13
         Purchases and Redemptions........................................  14
         How Portfolio Shares are Priced..................................  15
         Tax Consequences.................................................  16
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  17
         Financial Highlights.............................................  27
         Appendix A--Description of Securities Ratings.................... A-1
</TABLE>

                                                                  Prospectus
                                                                               2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                       Non-U.S.
                                                                                       Dollar
                                                                     Credit            Denominated
                                 Main Investments          Duration  Quality(1)        Securities(2)
- ----------------------------------------------------------------------------------------------------
 <C>           <C>               <S>                       <C>       <C>               <C>
 Intermediate  Total Return Bond Intermediate maturity     3-6 years B to Aaa; max 10%     0-20%(3)
 Duration                        fixed income securities             below Baa
 Bond
 Portfolios
         -------------------------------------------------------------------------------------------
               High Yield Bond   Higher yielding fixed     2-6 years B to Aaa; min 65%     0-15%(4)
                                 income securities                   below Baa
- ----------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  Each Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.
(4)  The percentage limitation relates to euro-denominated securities.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)
Fixed       The "Fixed Income Portfolios" are the Total Return Bond and the
Income      High Yield Bond Portfolios. Each of the Fixed Income Portfolios
Instruments differs from the other primarily in the length of the Portfolio's
            duration or the proportion of its investments in certain types of
            fixed income securities. Each Fixed Income Portfolio invests at
            least 65% of its assets in "Fixed Income Instruments," which as
            used in this Prospectus includes:

            . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio   The Portfolios provide a broad range of investment choices. The
Descrip-    following summaries identify each Portfolio's investment
tions,      objective, principal investments and strategies, principal risks,
Per-        performance information and fees and expenses. A more detailed
formance    "Summary of Principal Risks" describing principal risks of
and Fees    investing in the Portfolios begins after the Portfolio Summaries.

             It is possible to lose money on investments in the Portfolios.

             An investment in a Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.

                                                                  Prospectus
                                                                               4
<PAGE>

            PIMCO Total Return Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Intermediate         B to Aaa; maximum
and           Seeks maximum          maturity fixed       10% below Baa
Strategies    total return,          income
              consistent with        securities           Dividend Frequency
              preservation of                             Declared daily and
              capital and            Average Portfolio    distributed monthly
              prudent                Duration
              investment             3-6 years
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a three- to six-year time frame based on
            PIMCO's forecast for interest rates.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Derivatives         .  Currency Risk
                 Risk                   Risk                .  Leveraging
              .  Credit Risk         .  Liquidity Risk         Risk
              .  Market Risk         .  Mortgage Risk       .  Management
              .  Issuer Risk         .  Foreign                Risk
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


5  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Total Return Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

                                            Highest and Lowest Quarter Returns
                                            (for periods shown in the bar chart)
                                            --------------------
                                            Highest (3rd Qtr. '98)5.43%
                                            --------------------
   [GRAPH]                                  Lowest (2nd Qtr. '99)(0.94%)

1998    8.61%
1999   -0.58%


                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                         1 Year  (12/31/97)
            -----------------------------------------------
         <S>                             <C>     <C>
         Administrative Class            (0.58%) 3.91%
            -----------------------------------------------
         Lehman Aggregate Bond Index(1)  (0.82%) 3.82%
            -----------------------------------------------
</TABLE>

            (1) The Lehman Brothers Aggregate Bond Index is an unmanaged index
                of investment grade, U.S. dollar-denominated fixed income
                securities of domestic issuers having a maturity greater than
                one year. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual
                                                   Portfolio                 Net Portfolio
                         Advisory Service Other    Operating    Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses     Reduction(2) Expenses
            ------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>          <C>          <C>
         Administrative  0.25%    0.15%   0.29%(1) 0.69%        (0.04%)      0.65%
            ------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.04%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $217               $380               $855
            -----------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>

            PIMCO High Yield Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Higher yielding      B to Aaa; minimum
and           Seeks maximum          fixed income         65% below Baa
Strategies    total return,          securities
              consistent with                             Dividend Frequency
              preservation of        Average Portfolio    Declared daily and
              capital and            Duration             distributed monthly
              prudent                2-6 years
              investment
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of high yield securities ("junk bonds")
            rated below investment grade but rated at least B by Moody's or
            S&P, or, if unrated, determined by PIMCO to be of comparable
            quality. The remainder of the Portfolio's assets may be invested
            in investment grade Fixed Income Instruments. The average
            portfolio duration of this Portfolio normally varies within a two-
            to six-year time frame based on PIMCO's forecast for interest
            rates. The Portfolio may invest without limit in U.S. dollar-
            denominated securities of foreign issuers. The Portfolio may
            invest up to 15% of its assets in euro-denominated securities. The
            Portfolio normally will hedge at least 75% of its exposure to the
            euro to reduce the risk of loss due to fluctuations in currency
            exchange rates.

             The Portfolio may invest up to 15% of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements. The Portfolio may invest all of its assets in
            mortgage- or asset-backed securities. The Portfolio may lend its
            portfolio securities to brokers, dealers, and other financial
            institutions to earn income. The Portfolio may seek to obtain
            market exposure to the securities in which it primarily invests by
            entering into a series of purchase and sale contracts or by using
            other investment techniques (such as buy backs or dollar rolls).
            The "total return" sought by the Portfolio consists of income
            earned on the Portfolio's investments, plus capital appreciation,
            if any, which generally arises from decreases in interest rates or
            improving credit fundamentals for a particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Issuer Risk         .  Foreign
                 Risk                .  Liquidity Risk         Investment Risk
              .  Credit Risk         .  Derivatives Risk    .  Currency Risk
              .  High Yield Risk     .  Mortgage Risk       .  Leveraging Risk
              .  Market Risk                                .  Management Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


7
   PIMCO Variable Insurance Trust
<PAGE>

            PIMCO High Yield Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

                                            Highest and Lowest Quarter Returns
                                            (for periods shown in the bar chart)
                                            --------------------
   [GRAPH]                                  Highest (1st Qtr.'99)2.00%
                                            --------------------
1999     3.01%                              Lowest (2nd Qtr.'99)(0.51%)


                   Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                          1 Year (04/30/98)
            -----------------------------------------------
         <S>                              <C>    <C>
         Administrative Class             3.01%  2.88%
            -----------------------------------------------
         Lehman Brothers BB Intermediate
          Corporate Index(1)              2.20%  3.02%
            -----------------------------------------------
</TABLE>

            (1) The Lehman Brothers BB Intermediate Corporate Index is an
                unmanaged index comprised of various fixed income securities
                rated BB with an average duration of 4.40 years as of
                12/31/99. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.25%    0.15%   0.35%(1) 0.75%               0.00%        0.75%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.35% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.75% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $77                $240               $417               $930
            -----------------------------------------------------------------------------------
</TABLE>

                                                                 Prospectus    8
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

High        Portfolios that invest in high yield securities and unrated
Yield       securities of similar credit quality (commonly known as "junk
Risk        bonds") may be subject to greater levels of interest rate, credit
            and liquidity risk than Portfolios that do not invest in such
            securities. High yield securities are considered predominately
            speculative with respect to the issuer's continuing ability to
            make principal and interest payments. An economic downturn or
            period of rising interest rates could adversely affect the market
            for high yield securities and reduce a Portfolio's ability to sell
            its high yield securities (liquidity risk).

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

   PIMCO Variable Insurance Trust
9
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolios may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    Portfolios that invest directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies are subject to the risk that those currencies
            will decline in value relative to the U.S. dollar, or, in the case
            of hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary

                                                                  Prospectus
                                                                              10
<PAGE>

            Fund, or by the imposition of currency controls or other political
            developments in the U.S. or abroad. As a result, a Portfolio's
            investments in foreign currency-denominated securities may reduce
            the returns of a Portfolio.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

   PIMCO Variable Insurance Trust
11
<PAGE>

            Management of the Portfolios

Inves-      PIMCO serves as investment adviser and the administrator (serving
tment       in its capacity as administrator, the "Administrator") for the
Adviser     Portfolios. Subject to the supervision of the Board of Trustees,
and         PIMCO is responsible for managing the investment activities of the
Adminis-    Portfolios and the Portfolios' business affairs and other
trator      administrative matters.

             PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
            Beach, California 92660. Organized in 1971, PIMCO provides
            investment management and advisory services to private accounts of
            institutional and individual clients and to mutual funds. As of
            December 31, 1999, PIMCO had approximately $186 billion in assets
            under management.

Advisory    Each Portfolio pays PIMCO fees in return for providing investment
Fees        advisory services. For the fiscal year ended December 31, 1999,
            the Portfolios paid monthly advisory fees to PIMCO at the
            following annual rates (stated as a percentage of the average
            daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio                                               Advisory Fees
         ---------------------------------------------------------------------
         <S>                                                     <C>
         Total Return Bond Portfolio                                 0.40%
         High Yield Bond Portfolio                                   0.50%
</TABLE>

             Effective April 1, 2000, the Portfolios pay monthly advisory fees
            to PIMCO at the following annual rates (stated as a percentage of
            the average daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio
                                                                Advisory Fees
         --------------------------------------------------------------------
         <S>                                                    <C>
         All Portfolios                                             0.25%
</TABLE>

Adminis-    Each Portfolio pays for the administrative services it requires
rative      under a fee structure which is essentially fixed. Shareholders of
Fees        each Portfolio pay an administrative fee to PIMCO, computed as a
            percentage of the Portfolio's assets attributable in the aggregate
            to that class of shares. PIMCO, in turn, provides or procures
            administrative services for shareholders and also bears the costs
            of various third-party services required by the Portfolios,
            including audit, custodial, portfolio accounting, legal, transfer
            agency and printing costs. The result of this fee structure is an
            expense level for shareholders of each Portfolio that, with
            limited exceptions, is precise and predictable under ordinary
            circumstances.

             For the fiscal year ended December 31, 1999, the Portfolios paid
            PIMCO monthly administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio                                        Administrative Fees
         --------------------------------------------------------------------
         <S>                                              <C>
         All Portfolios                                          0.25%
</TABLE>

             Effective April 1, 2000, the Portfolios pay PIMCO monthly
            administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio                                        Administrative Fees
         --------------------------------------------------------------------
         <S>                                              <C>
         Total Return Bond Portfolio                             0.25%
         High Yield Bond Portfolio                               0.35%
</TABLE>

                                                                  Prospectus
                                                                              12
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

<TABLE>
<CAPTION>
                                                     Recent Professional
         Portfolio         Portfolio Manager  Since  Experience
         ----------------------------------------------------------------------

         <C>               <C>                <C>    <S>
         Total Return Bond William H. Gross   12/97* Managing Director, Chief
                                                     Investment Officer and a
                                                     founding partner of PIMCO.




         High Yield Bond   Benjamin L. Trosky  4/98* Managing Director, PIMCO.
                                                     He joined PIMCO as a
                                                     Portfolio Manager in 1990.

</TABLE>



            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

   PIMCO Variable Insurance Trust
13
<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of each Portfolio. The Plan allows the
            Portfolios to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits a Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of a Portfolio's Administrative Class assets on
            an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account

                                                                  Prospectus
                                                                              14
<PAGE>

            allocating assets to the Portfolios are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolios might be
            required to redeem the investment of one or more of its separate
            accounts from the Portfolios, which might force the Portfolios to
            sell securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolios to dispose of
            their securities or to determine fairly the value of their net
            assets, or during any other period as permitted by the SEC for the
            protection of investors. In the event that a Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Administrative Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.


15 PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.
            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus
                                                                              16
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  Most of the Portfolios in this prospectus seek maximum total
Selection   return. The total return sought by a Portfolio consists of both
            income earned on a Portfolio's investments and capital
            appreciation, if any, arising from increases in the market value
            of a Portfolio's holdings. Capital appreciation of fixed income
            securities generally results from decreases in market interest
            rates or improving credit fundamentals for a particular market
            sector or security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of a Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio may invest all of its assets in mortgage- and
Related     asset-backed securities. Mortgage-related securities include
and Other   mortgage pass-through securities, collateralized mortgage
Asset-      obligations ("CMOs"), commercial mortgage-backed securities,
Backed      mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities  securities ("SMBSs") and other securities that directly or
            indirectly represent a participation in, or are secured by and
            payable from, mortgage loans on real property.

   PIMCO Variable Insurance Trust
17
<PAGE>

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolios may
            invest in other asset-backed securities that have been offered to
            investors.

Loan        Certain Portfolios may invest in fixed- and floating-rate loans,
Participa-  which investments generally will be in the form of loan
tions       participations and assignments of portions of such loans.
and         Participations and assignments involve special types of risk,
Assign-     including credit risk, interest rate risk, liquidity risk, and the
ments       risks of being a lender. If a Portfolio purchases a participation,
            it may only be able to enforce its rights through the lender, and
            may assume the credit risk of the lender in addition to the
            borrower.

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

                                                                  Prospectus
                                                                              18
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

            Variable and floating rate securities provide for a periodic
Variable    adjustment in the interest rate paid on the obligations. Each
and         Portfolio may invest in floating rate debt instruments
Floating    ("floaters") and engage in credit spread trades. While floaters
Rate        provide a certain degree of protection against rises in interest
Securities  rates, a Portfolio will participate in any declines in interest
            rates as well. Each Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. A Portfolio may not invest more than 5% of
            its assets in any combination of inverse floater, interest only,
            or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      Each Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

   PIMCO Variable Insurance Trust
19
<PAGE>

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

            Investing in the securities of issuers in any foreign country
Foreign     involves special risks and considerations not typically associated
(Non-       with investing in U.S. companies. Shareholders should consider
U.S.)       carefully the substantial risks involved for Portfolios that
Securities  invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             Certain Portfolios also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. Each Portfolio that may invest in
            foreign securities, may invest up to 10% of its assets in
            securities of issuers based in countries with developing (or
            "emerging market") economies. Investing in emerging market
            securities imposes risks different from, or greater than, risks of
            investing in domestic securities or in foreign, developed
            countries. These risks include: smaller market capitalization of
            securities markets, which may suffer periods of relative
            illiquidity; significant price volatility; restrictions on foreign
            investment; possible repatriation of investment income and
            capital. In addition, foreign investors may be required to
            register the proceeds of sales; future economic or political
            crises could lead to price controls, forced mergers, expropriation
            or confiscatory taxation, seizure, nationalization, or creation of
            government monopolies. The currencies of emerging market countries
            may experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                Prospectus
                                                                              20
<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             Each Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolios' assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolios.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into
            forward foreign currency exchange contracts and invest in foreign
            currency futures contracts and options on foreign currencies and
            futures. A forward foreign currency exchange contract, which
            involves an obligation to purchase or sell a specific currency at
            a future date at a price set at the time of the contract, reduces
            a Portfolio's exposure to changes in the value of the currency it
            will deliver and increases its exposure
            to changes in the value of the currency it will receive for the
            duration of the contract. The effect on the value of a Portfolio
            is similar to selling securities denominated in one currency and
            purchasing securities denominated in another currency. A contract
            to sell foreign currency would limit any potential gain which
            might be realized if the value of the hedged currency increases. A
            Portfolio may enter into these contracts to hedge against foreign
            exchange risk, to increase exposure to a foreign currency or to
            shift exposure to foreign currency fluctuations from one currency
            to another. Suitable hedging transactions may not be available in
            all circumstances and there can be no assurance that a Portfolio
            will engage in such transactions at any given time or from time to
            time. Also, such transactions may not be successful and may
            eliminate any chance for a Portfolio to benefit from favorable
            fluctuations in relevant foreign currencies. A Portfolio may use
            one currency (or a basket of currencies) to hedge against adverse
            changes in the value of another currency (or a basket of
            currencies) when exchange rates between the two currencies are
            positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations
            under forward foreign currency exchange contracts entered into for
            non-hedging purposes.

Repurchase  Each Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


   PIMCO Variable Insurance Trust
21
<PAGE>

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. Each Portfolio may
            invest all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolios may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus
                                                                              22
<PAGE>

            each Portfolio will segregate assets determined to be liquid by
            PIMCO in accordance with procedures established by the Board of
            Trustees (or, as permitted by applicable regulation, enter into
            certain offsetting positions) to cover its obligations under
            derivative instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolios may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring a Portfolio to increase its investment in
Facilities  a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            a Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       Each Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Transac-    settlement date. This risk is in addition to the risk that the
tions       Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase a
            Portfolio's overall investment exposure. Typically, no income
            accrues on securities a Portfolio has committed to purchase prior
            to the time delivery of the securities is made, although a
            Portfolio may earn income on securities it has segregated to cover
            these positions.


   PIMCO Variable Insurance Trust
23
<PAGE>

Investment  Each Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, a Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, each
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       Each Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    Each Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.


                                                                   Prospectus
                                                                              24
<PAGE>

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

   PIMCO Variable Insurance Trust
25
<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                  Prospectus
                                                                              26
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Total Return
 Administrative Class
 12/31/1999            $10.09     $0.58        $(0.64)(a)    $(0.06)     $(0.58)      $0.00        $ 0.00         $0.00
 12/31/1998(c)          10.00      0.56          0.28 (a)      0.84       (0.56)       0.00         (0.19)         0.00
High Yield
 Administrative Class
 12/31/1999            $ 9.67     $0.77        $(0.49)(a)    $ 0.28      $(0.77)      $0.00        $ 0.00         $0.00
 12/31/1998(d)          10.00      0.51         (0.34)(a)      0.17       (0.50)       0.00          0.00          0.00
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(c) Commenced operations on December 31, 1997.
(d) Commenced operations on April 30, 1998.

   PIMCO Variable Insurance Trust
27
<PAGE>




<TABLE>
<CAPTION>
                                                                     Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of      Investment
 Return                    Value               End     Expenses to    Income to   Portfolio
   of          Total        End    Total    of Period    Average       Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets     Net Assets    Rate
- -------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>           <C>          <C>


  $0.00       $(0.58)     $ 9.45   (0.58)%   $  3,877     0.65% (b)      5.96%       102%
   0.00        (0.75)      10.09    8.61        3,259     0.65           5.55        139


  $0.00       $(0.77)     $ 9.18    3.01 %   $151,020     0.75%          8.25%        13%
   0.00        (0.50)       9.67    1.80       49,761     0.75           7.90*        13
</TABLE>
- -------
*   Annualized.
(b) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.69% for the
    period ended December 31, 1999.

                                                                  Prospectus
                                                                              28
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

   PIMCO Variable Insurance Trust
A-1
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

                                                                  Prospectus
                                                                             A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

   PIMCO Variable Insurance Trust
A-3
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

                                                                  Prospectus
                                                                             A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington, D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.


                             [LOGO OF PIMCO FUNDS]

PIMCO Funds

840 Newport Center Drive
Suite 300
Newport Beach, CA 92660
<PAGE>

PIMCO
Variable
Insurance
Trust

April 1, 2000

Share Class

Adm Administrative


PIMCO Funds Prospectus



- --------------------------------------------------------------------------------
SHORT DURATION BOND PORTFOLIO
Money Market Portfolio

- --------------------------------------------------------------------------------
INTERMEDIATE DURATION BOND PORTFOLIO
Total Return Bond Portfolio

- --------------------------------------------------------------------------------
INTERNATIONAL BOND PORTFOLIO
Foreign Bond Portfolio

- --------------------------------------------------------------------------------
STOCK PORTFOLIO
StocksPLUS Growth and Income Portfolio






This cover is not part of the Prospectus                   [LOGO OF PIMCO FUNDS]
<PAGE>

            Prospectus


PIMCO       This Prospectus describes 4 separate investment portfolios (the
Variable    "Portfolios"), offered by the PIMCO Variable Insurance Trust (the
Insurance   "Trust"). The Portfolios provide access to the professional
Trust       investment management services offered by Pacific Investment
            Management Company ("PIMCO"). The investments made by the
April 1,    Portfolios at any given time are not expected to be the same as
2000        those made by other mutual funds for which PIMCO acts as
            investment adviser, including mutual funds with investment
Share       objectives and strategies similar to those of the Portfolios.
Class       Accordingly, the performance of the Portfolios can be expected to
Adminis-    vary from that of the other mutual funds.
trative
            This Prospectus explains what you should know about the Portfolios
            before you invest. Please read it carefully.

            Shares of the Portfolios currently are sold to segregated asset
            accounts ("Separate Accounts") of insurance companies that fund
            variable annuity contracts and variable life insurance policies
            ("Variable Contracts"). Assets in the Separate Account are
            invested in shares of the Portfolios in accordance with allocation
            instructions received from owners of the Variable Contracts
            ("Variable Contract Owners"). Variable Contract Owners do not deal
            directly with the Portfolios to purchase or redeem shares. The
            allocation rights of Variable Contract Owners are described in the
            accompanying Separate Account prospectus. Shares of the Portfolios
            also may be sold to qualified pension and retirement plans outside
            of the separate account context.

            This Prospectus should be read in conjunction with the prospectus
            of the Separate Account. Both prospectuses should be read
            carefully and retained for future reference.

            The Securities and Exchange Commission has not approved or
            disapproved these securities, or determined if this Prospectus is
            truthful or complete. Any representation to the contrary is a
            criminal offense.

   PIMCO Variable Insurance Trust
1
<PAGE>

            Table of Contents

<TABLE>
         <S>                                                               <C>
         Summary Information..............................................   3
         Portfolio Summaries..............................................   5
           Money Market Portfolio.........................................   5
           Total Return Bond Portfolio....................................   7
           Foreign Bond Portfolio.........................................   9
           StocksPLUS Growth and Income Portfolio.........................  11
         Summary of Principal Risks.......................................  13
         Management of the Portfolios.....................................  16
         Investment Options...............................................  17
         Purchases and Redemptions........................................  18
         How Portfolio Shares are Priced..................................  19
         Tax Consequences.................................................  20
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  21
         Financial Highlights.............................................  31
         Appendix A--Description of Securities Ratings.................... A-1
</TABLE>

                                                                  Prospectus
                                                                               2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                            Main Investments   Duration                         Credit Quality(1)
- -------------------------------------------------------------------------------------------------------------------------------
 <C>           <C>                          <S>                <C>                              <C>
 Short         Money Market                 Money market       (less than or =) 90 days dollar- Min 95% Aaa or
 Duration                                   instruments        weighted average                 Prime 1; (less than or =) 5% Aa
 Bond                                                          maturity                         or Prime 2
 Portfolio
- -------------------------------------------------------------------------------------------------------------------------------
 Intermediate  Total Return Bond            Intermediate       3-6 years                        B to Aaa; max 10%
 Duration Bond                              maturity fixed                                      below Baa
 Portfolio                                  income
                                            securities
- -------------------------------------------------------------------------------------------------------------------------------
 International Foreign Bond                 Intermediate       3-7 years                        B to Aaa; max
 Bond                                       maturity hedged                                     10% below Baa
 Portfolio                                  non-U.S. fixed
                                            income
                                            securities
- -------------------------------------------------------------------------------------------------------------------------------
 Stock         StocksPLUS Growth and Income S&P 500 stock      0-1 year                         B to Aaa; max
 Portfolio                                  index                                               10% below Baa
                                            derivatives
                                            backed by a
                                            portfolio of
                                            short-term
                                            fixed-income
                                            securities
- -------------------------------------------------------------------------------------------------------------------------------
<CAPTION>
                    Non-U.S. Dollar
                    Denominated Securities(2)
- -------------------------------------------------------------------------------------------------------------------------------
                    <S>
                    0%
- -------------------------------------------------------------------------------------------------------------------------------
                    0-20%(3)
- -------------------------------------------------------------------------------------------------------------------------------
                    (greater than or =) 85%(4)
- -------------------------------------------------------------------------------------------------------------------------------
                    0-20%(3)
- -------------------------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  Each Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.
(4)  The percentage limitation relates to securities of foreign issuers,
     denominated in any currency.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)
Fixed       The "Fixed Income Portfolios" are the Money Market, the Total
Income      Return Bond and the Foreign Bond Portfolios. Each of the Fixed
Instruments Income Portfolios differs from the others primarily in the length
            of the Portfolio's duration or the proportion of its investments
            in certain types of fixed income securities. Each Fixed Income
            Portfolio invests at least 65% of its assets in "Fixed Income
            Instruments," which as used in this Prospectus includes:

            . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio   The Portfolios provide a broad range of investment choices. The
Descrip-    following summaries identify each Portfolio's investment
tions,      objective, principal investments and strategies, principal risks,
Performance performance information and fees and expenses. A more detailed
and Fees    "Summary of Principal Risks" describing principal risks of
            investing in the Portfolios begins after the Portfolio Summaries.

             It is possible to lose money on investments in the Portfolios.

             An investment in a Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.

                                                                  Prospectus
                                                                               4
<PAGE>

            PIMCO Money Market Portfolio

- --------------------------------------------------------------------------------
Principal     Investment Objective  Portfolio Focus      Credit Quality
Investments   Seeks maximum         Money market         Minimum 95% rated Aaa
and           current income,       instruments          or Prime 1; (less
Strategies    consistent with                            than or =)5% Aa or
              preservation of       Average              Prime 2
              capital and           Portfolio
              daily liquidity       Maturity             Dividend Frequency
                                    (less than or =)     Declared daily and
                                    90 days dollar-      distributed monthly
                                    weighted average
                                    maturity

            The Portfolio seeks to achieve its investment objective by
            investing at least 95% of its total assets in a diversified
            portfolio of money market securities that are in the highest
            rating category for short-term obligations. The Portfolio also may
            invest up to 5% of its total assets in money market securities
            that are in the second-highest rating category for short-term
            obligations. The Portfolio may only invest in U.S. dollar-
            denominated securities that mature in 397 days or fewer from the
            date of purchase. The dollar-weighted average portfolio maturity
            of the Portfolio may not exceed 90 days. The Portfolio attempts to
            maintain a stable net asset value of $1.00 per share, although
            there is no assurance that it will be successful in doing so.

             The Portfolio may invest in the following: obligations of the
            U.S. Government (including its agencies and government-sponsored
            enterprises); short-term corporate debt securities of domestic and
            foreign corporations; obligations of domestic and foreign
            commercial banks, savings banks, and savings and loan
            associations; and commercial paper. The Portfolio may invest more
            than 25% of its total assets in securities or obligations issued
            by U.S. banks. The Portfolio may lend its portfolio securities to
            brokers, dealers and other financial institutions in order to earn
            income.

             The Portfolio's investments will comply with applicable rules
            governing the quality, maturity and diversification of securities
            held by money market funds.

- --------------------------------------------------------------------------------
Principal   An investment in the Portfolio is not insured or guaranteed by the
Risks       Federal Deposit Insurance Corporation or any other government
            agency. Although the Portfolio seeks to preserve the value of your
            investment at $1.00 per share, it is possible to lose money by
            investing in the Portfolio. Among the principal risks of investing
            in the Portfolio, which could adversely affect its net asset
            value, yield and total return, are:

              .  Interest Rate      .  Market Risk
                 Risk               .  Issuer Risk
              .  Credit Risk
              .  Management Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.

   PIMCO Variable Insurance Trust
5
<PAGE>

            PIMCO Money Market Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.15%    0.15%   0.97%(1) 1.27%               (0.77%)      0.50%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.20% administrative fee and 0.77%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.50% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class                         Year 1                                         Year 3
            --------------------------------------------------------------------------------------
         <S>                                 <C>                                            <C>
         Administrative                       $51                                            $327
            --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>

            PIMCO Total Return Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Intermediate         B to Aaa; maximum
and           Seeks maximum          maturity fixed       10% below Baa
Strategies    total return,          income
              consistent with        securities           Dividend Frequency
              preservation of                             Declared daily and
              capital and            Average Portfolio    distributed monthly
              prudent                Duration
              investment             3-6 years
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a three- to six-year time frame based on
            PIMCO's forecast for interest rates.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Derivatives         .  Currency Risk
                 Risk                   Risk                .  Leveraging
              .  Credit Risk         .  Liquidity Risk         Risk
              .  Market Risk         .  Mortgage Risk       .  Management
              .  Issuer Risk         .  Foreign                Risk
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


7  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Total Return Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

   [GRAPH]              Highest and Lowest Quarter Returns
                        (for periods shown in the bar chart)
'98     8.61%           --------------------
'99    -0.58%           Highest (3rd Qtr. '98)5.43%
                        --------------------
                        Lowest (2nd Qtr. '99)(0.94%)

                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                         1 Year  (12/31/97)
         --------------------------------------------------
         <S>                             <C>     <C>
         Administrative Class            (0.58%) 3.91%
         --------------------------------------------------
         Lehman Aggregate Bond Index(1)  (0.82%) 3.82%
         --------------------------------------------------
</TABLE>

            (1) The Lehman Brothers Aggregate Bond Index is an unmanaged index
                of investment grade, U.S. dollar-denominated fixed income
                securities of domestic issuers having a maturity greater than
                one year. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual
                                                   Portfolio                 Net Portfolio
                         Advisory Service Other    Operating    Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses     Reduction(2) Expenses
         ---------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>          <C>          <C>
         Administrative  0.25%    0.15%   0.29%(1) 0.69%        (0.04%)      0.65%
         ---------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.04%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
         --------------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $217               $380               $855
         --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   8
<PAGE>

            PIMCO Foreign Bond Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Intermediate         B to Aaa; maximum
and           Seeks maximum          maturity hedged      10% below Baa
Strategies    total return,          non-U.S. fixed
              consistent with        income securities    Dividend
              preservation of                             Frequency
              capital and            Average Portfolio
              prudent                Duration             Declared daily and
              investment             3-7 years            distributed monthly
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 85% of its assets in
            Fixed Income Instruments of issuers located outside the United
            States, representing at least three foreign countries, which may
            be represented by futures contracts (including related options)
            with respect to such securities, and options on such securities.
            Such securities normally are denominated in major foreign
            currencies or baskets of foreign currencies (such as the euro).
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             PIMCO selects the Portfolio's foreign country and currency
            compositions based on an evaluation of various factors, including,
            but not limited to, relative interest rates, exchange rates,
            monetary and fiscal policies, trade and current account balances.
            The average portfolio duration of this Portfolio normally varies
            within a three- to seven-year time frame. The Portfolio invests
            primarily in investment grade debt securities, but may invest up
            to 10% of its assets in high yield securities ("junk bonds") rated
            B or higher by Moody's or S&P, or, if unrated, determined by PIMCO
            to be of comparable quality. The Portfolio is non-diversified,
            which means that it may concentrate its assets in a smaller number
            of issuers than a diversified Portfolio.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal Risks
            Among the principal risks of investing in the Portfolio, which
            could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Foreign             .  Mortgage Risk
                 Risk                   Investment Risk     .  Derivatives Risk
              .  Credit Risk         .  Currency Risk       .  Leveraging Risk
              .  Market Risk         .  Issuer Non-         .  Management Risk
              .  Issuer Risk            Diversification
                                        Risk
                                     .  Liquidity Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.
- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.

9  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Foreign Bond Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         Administrative  0.25%    0.15%   0.85%(1) 1.25%               (0.15%)      1.10%(3)
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.50% administrative fee, 0.20%
                interest expense, and 0.15% representing the Portfolio's
                organizational expenses as attributed to the class and pro
                rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.90% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.
            (3) Ratio of net expenses to average net assets excluding interest
                expense is 0.90% for the Administrative Class.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
         <S>                                 <C>                                            <C>
         Share Class                         Year 1                                         Year 3
            --------------------------------------------------------------------------------------
         Administrative                      $112                                           $382
            --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus
                                                                              10
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              S&P 500 stock        B to Aaa; maximum
and                                  index derivatives    10% below Baa
Strategies    Seeks total            backed by a
              return which           portfolio of         Dividend
              exceeds that of        short-term fixed     Frequency
              the S&P 500            income securities    Declared and
                                                          distributed
                                     Average Portfolio    quarterly
                                     Duration
                                     0-1 year

            The Portfolio seeks to exceed the total return of the S&P 500 by
            investing under normal circumstances substantially all of its
            assets in S&P 500 derivatives, backed by a portfolio of Fixed
            Income Instruments. The Portfolio may invest in common stocks,
            options, futures, options on futures and swaps. The Portfolio uses
            S&P 500 derivatives in addition to or in place of S&P 500 stocks
            to attempt to equal or exceed the performance of the S&P 500. The
            value of S&P 500 derivatives closely track changes in the value of
            the index. However, S&P 500 derivatives may be purchased with a
            fraction of the assets that would be needed to purchase the equity
            securities directly, so that the remainder of the assets may be
            invested in Fixed Income Instruments. PIMCO actively manages the
            fixed income assets held by the Portfolio with a view toward
            enhancing the Portfolio's total return, subject to an overall
            portfolio duration which is normally not expected to exceed one
            year.

             The S&P 500 is composed of 500 selected common stocks that
            represent approximately two-thirds of the total market value of
            all U.S. common stocks. The Portfolio is neither sponsored by nor
            affiliated with S&P. The Portfolio seeks to remain invested in S&P
            500 derivatives or S&P 500 stocks even when the S&P 500 is
            declining.

             Though the Portfolio does not normally invest directly in S&P 500
            securities, when S&P 500 derivatives appear to be overvalued
            relative to the S&P 500, the Portfolio may invest all of its
            assets in a "basket" of S&P 500 stocks. Individual stocks are
            selected based on an analysis of the historical correlation
            between the return of every S&P 500 stock and the return on the
            S&P 500 itself. PIMCO may employ fundamental analysis of factors
            such as earnings and earnings growth, price to earnings ratio,
            dividend growth, and cash flows to choose among stocks that
            satisfy the correlation tests. Stocks chosen for the Portfolio are
            not limited to those with any particular weighting in the S&P 500.
            The Portfolio may also invest in exchange traded funds based on
            the S&P 500, such as Standard & Poor's Depositary Receipt.

             Assets not invested in equity securities or derivatives may be
            invested in Fixed Income Instruments. The Portfolio may invest up
            to 10% of its assets in high yield securities ("junk bonds") rated
            B or higher by Moody's or S&P, or, if unrated, determined by PIMCO
            to be of comparable quality. The Portfolio may invest up to 20% of
            its assets in securities denominated in foreign currencies and may
            invest beyond this limit in U.S. dollar denominated securities of
            foreign issuers. The Portfolio will normally hedge at least 75% of
            its exposure to foreign currency to reduce the risk of loss due to
            fluctuations in currency exchange rates. In addition, the
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income.

- --------------------------------------------------------------------------------
Principal   Under certain conditions, generally in a market where the value of
Risks       both S&P 500 derivatives and fixed income securities are
            declining, the Portfolio may experience greater losses than would
            be the case if it invested directly in a portfolio of S&P 500
            stocks. Among the principal risks of investing in the Portfolio,
            which could adversely affect its net asset value, yield and total
            return, are:

              . Market Risk          . Interest Rate        . Mortgage Risk
              . Issuer Risk             Risk                . Leveraging Risk
              . Derivatives Risk     . Liquidity Risk       . Management Risk
              . Credit Risk          . Foreign
                                        Investment
                                        Risk
                                     . Currency Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.
- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.

11 PIMCO Variable Insurance Trust
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

   [GRAPH]        Highest and Lowest Quarter Returns
                  (for periods shown in the bar chart)
'98     30.11%    --------------------
'99     19.85%    Highest (4th Qtr. '98)21.95%
                  --------------------
                  Lowest (3rd Qtr. '98)-8.82%


                  Calendar Year End (through 12/31)

            Average Annual Total Returns (for periods ended 12/31/99)
<TABLE>
<CAPTION>
                                                                                   Portfolio
                                                                                   Inception
                                              1 Year                               (12/31/97)
         ------------------------------------------------------------------------------------
         <S>                                  <C>                                  <C>
         Administrative Class                 19.85%                               24.87%
         ------------------------------------------------------------------------------------
         S&P 500 Index(1)                     21.04%                               24.75%
         ------------------------------------------------------------------------------------
</TABLE>

            (1) The Standard & Poor's 500 Composite Stock Price Index is an
                unmanaged index of common stocks. It is not possible to invest
                directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
         ----------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.40%    0.15%   0.10%(1) 0.65%               0.00%        0.65%
         ----------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflects a 0.10% administrative fee.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operation expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
         --------------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $208               $362               $810
         --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus  12
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

   PIMCO Variable Insurance Trust
13
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolios may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    Portfolios that invest directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies are subject to the risk that those currencies
            will decline in value relative to the U.S. dollar, or, in the case
            of hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary

                                                                Prospectus
                                                                              14
<PAGE>

            Fund, or by the imposition of currency controls or other political
            developments in the U.S. or abroad. As a result, a Portfolio's
            investments in foreign currency-denominated securities may reduce
            the returns of a Portfolio.

Issuer      Focusing investments in a small number of issuers, industries or
Non-        foreign currencies increases risk. Portfolios that are "non-
Diversifi-  diversified" may invest a greater percentage of their assets in
cation      the securities of a single issuer (such as bonds issued by a
Risk        particular state) than Portfolios that are "diversified."
            Portfolios that invest in a relatively small number of issuers are
            more susceptible to risks associated with a single economic,
            political or regulatory occurrence than a more diversified
            portfolio might be. Some of those issuers also may present
            substantial credit or other risks. Similarly, a Portfolio may be
            more sensitive to adverse economic, business or political
            developments if it invests a substantial portion of its assets in
            the bonds of similar projects or from issuers in the same state.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

   PIMCO Variable Insurance Trust
15
<PAGE>

            Management of the Portfolios

Invest-     PIMCO serves as investment adviser and the administrator (serving
ment        in its capacity as administrator, the "Administrator") for the
Adviser     Portfolios. Subject to the supervision of the Board of Trustees,
and         PIMCO is responsible for managing the investment activities of the
Admini-     Portfolios and the Portfolios' business affairs and other
strator     administrative matters.

             PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
            Beach, California 92660. Organized in 1971, PIMCO provides
            investment management and advisory services to private accounts of
            institutional and individual clients and to mutual funds. As of
            December 31, 1999, PIMCO had approximately $186 billion in assets
            under management.

Advisory    Each Portfolio pays PIMCO fees in return for providing investment
Fees        advisory services. For the fiscal year ended December 31, 1999,
            the Portfolios paid monthly advisory fees to PIMCO at the
            following annual rates (stated as a percentage of the average
            daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio                                  Advisory Fees
         ---------------------------------------------------------------------
         <S>                                     <C>
         Money Market Portfolio                         0.30%
         Foreign Bond Portfolio                         0.60%
         All other Portfolios                           0.40%
</TABLE>
             Effective April 1, 2000, the Portfolios pay monthly advisory fees
            to PIMCO at the following annual rates (stated as a percentage of
            the average daily net assets of each Portfolio taken separately):
<TABLE>
<CAPTION>
         Portfolio
                                                    Advisory Fees
         ---------------------------------------------------------------------
         <S>                                     <C>
         Money Market Portfolio                         0.15%
         StocksPLUS Growth and Income Portfolio         0.40%
         All other Portfolios                           0.25%
</TABLE>

Admini-     Each Portfolio pays for the administrative services it requires
strative    under a fee structure which is essentially fixed. Shareholders of
Fees        each Portfolio pay an administrative fee to PIMCO, computed as a
            percentage of the Portfolio's assets attributable in the aggregate
            to that class of shares. PIMCO, in turn, provides or procures
            administrative services for shareholders and also bears the costs
            of various third-party services required by the Portfolios,
            including audit, custodial, portfolio accounting, legal, transfer
            agency and printing costs. The result of this fee structure is an
            expense level for shareholders of each Portfolio that, with
            limited exceptions, is precise and predictable under ordinary
            circumstances.

             For the fiscal year ended December 31, 1999, the Portfolios paid
            PIMCO monthly administrative fees at the following annual rates:
<TABLE>
<CAPTION>
         Portfolio                               Administrative Fees
         ---------------------------------------------------------------------
         <S>                                     <C>
         Money Market Portfolio                         0.20%
         Foreign Bond Portfolio                         0.30%
         All other Portfolios                           0.25%
</TABLE>
             Effective April 1, 2000, the Portfolios pay PIMCO monthly
            administrative fees at the following annual rates:
<TABLE>
<CAPTION>
         Portfolio                               Administrative Fees
         ---------------------------------------------------------------------
         <S>                                     <C>
         Money Market Portfolio                         0.20%
         Total Return Bond Portfolio                    0.25%
         Foreign Bond Portfolio                         0.50%
         StocksPLUS Growth & Income Portfolio           0.10%
</TABLE>

                                                                  Prospectus
                                                                              16
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

<TABLE>
<CAPTION>
         Portfolio          Portfolio Manager  Since  Recent Professional Experience
            ----------------------------------------------------------------------------------------------
         <C>                <C>                <C>    <S>
         Money Market       Paul A. McCulley    9/99* Executive Vice President, PIMCO. He has managed
                                                      fixed income assets since joining PIMCO in 1999.
                                                      Prior to joining PIMCO, Mr. McCulley was associated
                                                      with Warburg Dillon Read as a Managing Director from
                                                      1992-1999 and Head of Economic and Strategy Research
                                                      for the Americas from 1995-1999, where he managed
                                                      macro research world-wide.

         Total Return Bond  William H. Gross   12/97* Managing Director, Chief Investment Officer and a
         StocksPLUS                            12/97* founding partner of PIMCO. He leads a team which
          Growth and Income                           manages the StocksPLUS Portfolio.

         Foreign Bond       Lee R. Thomas, III  2/99* Managing Director and Senior International Portfolio
                                                      Manager, PIMCO. He joined PIMCO as a Portfolio
                                                      Manager in 1995, and has managed fixed income
                                                      accounts for various institutional clients and funds
                                                      since that time. Prior to joining PIMCO, he was
                                                      associated with Investcorp as a member of the
                                                      management committee responsible for global
                                                      securities and foreign exchange trading.
</TABLE>
            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

   PIMCO Variable Insurance Trust
17
<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of each Portfolio. The Plan allows the
            Portfolios to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits a Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of a Portfolio's Administrative Class assets on
            an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account

                                                                  Prospectus
                                                                              18
<PAGE>

            allocating assets to the Portfolios are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolios might be
            required to redeem the investment of one or more of its separate
            accounts from the Portfolios, which might force the Portfolios to
            sell securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolios to dispose of
            their securities or to determine fairly the value of their net
            assets, or during any other period as permitted by the SEC for the
            protection of investors. In the event that a Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Administrative Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             Except for the Money Market Portfolio, for purposes of
            calculating NAV, portfolio securities and other assets for which
            market quotes are available are stated at market value. Market
            value is generally determined on the basis of last reported sales
            prices, or if no sales are reported, based on quotes obtained from
            a quotation reporting system, established market makers, or
            pricing services. Certain securities or investments for which
            daily market quotations are not readily available may be valued,
            pursuant to guidelines established by the Board of Trustees, with
            reference to other securities or indices. Short-term investments
            having a maturity of 60 days or less are generally valued at
            amortized cost. Exchange traded options, futures and options on
            futures are valued at the settlement price determined by the
            exchange. Other securities for which market quotes are not readily
            available are valued at fair value as determined in good faith by
            the Board of Trustees or persons acting at their direction.

             The Money Market Portfolio's securities are valued using the
            amortized cost method of valuation, which involves valuing a
            security at cost on the date of acquisition and thereafter
            assuming a constant accretion of a discount or amortization of a
            premium to maturity, regardless of the impact of fluctuating
            interest rates on the market value of the instrument. While this
            method provides certainty in valuation, it may result in periods
            during which value, as determined by amortized cost, is higher or
            lower than the price the Portfolio would receive if it sold the
            instrument.

19 PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus
                                                                              20
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  Most of the Portfolios in this prospectus seek maximum total
Selection   return. The total return sought by a Portfolio consists of both
            income earned on a Portfolio's investments and capital
            appreciation, if any, arising from increases in the market value
            of a Portfolio's holdings. Capital appreciation of fixed income
            securities generally results from decreases in market interest
            rates or improving credit fundamentals for a particular market
            sector or security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of a Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio (except the Money Market Portfolio) may invest all
Related     of its assets in mortgage- and asset-backed securities. Mortgage-
and Other   related securities include mortgage pass-through securities,
Asset-      collateralized mortgage obligations ("CMOs"), commercial mortgage-
Backed      backed securities, mortgage dollar rolls, CMO residuals, stripped
Securities  mortgage-backed securities ("SMBSs") and other securities that
            directly or indirectly represent a participation in, or are
            secured by and payable from, mortgage loans on real property.

   PIMCO Variable Insurance Trust
21
<PAGE>

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolios may
            invest in other asset-backed securities that have been offered to
            investors.

Loan        Certain Portfolios may invest in fixed- and floating-rate loans,
Participa-  which investments generally will be in the form of loan
tions       participations and assignments of portions of such loans.
and         Participations and assignments involve special types of risk,
Assign-     including credit risk, interest rate risk, liquidity risk, and the
ments       risks of being a lender. If a Portfolio purchases a participation,
            it may only be able to enforce its rights through the lender, and
            may assume the credit risk of the lender in addition to the
            borrower.

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

                                                                  Prospectus
                                                                              22
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

            Variable and floating rate securities provide for a periodic
Variable    adjustment in the interest rate paid on the obligations. Each
and         Portfolio may invest in floating rate debt instruments
Floating    ("floaters") and (except for the Money Market Portfolio) engage in
Rate        credit spread trades. While floaters provide a certain degree of
Securities  protection against rises in interest rates, a Portfolio will
            participate in any declines in interest rates as well. Each
            Portfolio (except the Money Market Portfolio) may also invest in
            inverse floating rate debt instruments ("inverse floaters"). An
            inverse floater may exhibit greater price volatility than a fixed
            rate obligation of similar credit quality. A Portfolio may not
            invest more than 5% of its assets in any combination of inverse
            floater, interest only, or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      Each Portfolio (except the Money Market Portfolio) may invest in
Linked      "event-linked bonds," which are fixed income securities for which
Bonds       the return of principal and payment of interest is contingent on
            the non-occurrence of a specific "trigger" event, such as a
            hurricane, earthquake or other physical or weather-related
            phenomenon. Some event-linked bonds are commonly referred to as
            "catastrophe bonds." If a trigger event occurs, a Portfolio may
            lose a portion or all of its principal invested in the bond.
            Event-linked bonds often provide for an extension of maturity to
            process and audit loss claims where a trigger event has, or
            possibly has, occurred. Event-linked bonds may also expose the
            Portfolio to certain unanticipated risks including but not limited
            to issuer (credit) default, adverse regulatory or jurisdictional
            interpretation, and adverse tax consequences. Event-linked bonds
            may also be subject to liquidity risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

  PIMCO Variable Insurance Trust
23
<PAGE>

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

            Investing in the securities of issuers in any foreign country
Foreign     involves special risks and considerations not typically associated
(Non-       with investing in U.S. companies. Shareholders should consider
U.S.)       carefully the substantial risks involved for Portfolios that
Securities  invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             Certain Portfolios also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. Each Portfolio that may invest in
            foreign securities may invest up to 10% of its assets in the
            securities of issuers based in countries with developing (or
            "emerging market") economies. Investing in emerging market
            securities imposes risks different from, or greater than, risks of
            investing in domestic securities or in foreign, developed
            countries. These risks include: smaller market capitalization of
            securities markets, which may suffer periods of relative
            illiquidity; significant price volatility; restrictions on foreign
            investment; possible repatriation of investment income and
            capital. In addition, foreign investors may be required to
            register the proceeds of sales; future economic or political
            crises could lead to price controls, forced mergers, expropriation
            or confiscatory taxation, seizure, nationalization, or creation of
            government monopolies. The currencies of emerging market countries
            may experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                Prospectus
                                                                              24
<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             Each Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolios' assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolios.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into
            forward foreign currency exchange contracts and invest in foreign
            currency futures contracts and options on foreign currencies and
            futures. A forward foreign currency exchange contract, which
            involves an obligation to purchase or sell a specific currency at
            a future date at a price set at the time of the contract, reduces
            a Portfolio's exposure to changes in the value of the currency it
            will deliver and increases its exposure
            to changes in the value of the currency it will receive for the
            duration of the contract. The effect on the value of a Portfolio
            is similar to selling securities denominated in one currency and
            purchasing securities denominated in another currency. A contract
            to sell foreign currency would limit any potential gain which
            might be realized if the value of the hedged currency increases. A
            Portfolio may enter into these contracts to hedge against foreign
            exchange risk, to increase exposure to a foreign currency or to
            shift exposure to foreign currency fluctuations from one currency
            to another. Suitable hedging transactions may not be available in
            all circumstances and there can be no assurance that a Portfolio
            will engage in such transactions at any given time or from time to
            time. Also, such transactions may not be successful and may
            eliminate any chance for a Portfolio to benefit from favorable
            fluctuations in relevant foreign currencies. A Portfolio may use
            one currency (or a basket of currencies) to hedge against adverse
            changes in the value of another currency (or a basket of
            currencies) when exchange rates between the two currencies are
            positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations
            under forward foreign currency exchange contracts entered into for
            non-hedging purposes.

Repurchase  Each Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


   PIMCO Variable Insurance Trust
25
<PAGE>

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio (except the Money Market Portfolio) may, but is not
            required to, use derivative instruments for risk management
            purposes or as part of its investment strategies. Generally,
            derivatives are financial contracts whose value depends upon, or
            is derived from, the value of an underlying asset, reference rate
            or index, and may relate to stocks, bonds, interest rates,
            currencies or currency exchange rates, commodities, and related
            indexes. Examples of derivative instruments include options
            contracts, futures contracts, options on futures contracts and
            swap agreements. Each Portfolio may invest all of its assets in
            derivative instruments, subject to the Portfolio's objective and
            policies. A portfolio manager may decide not to employ any of
            these strategies and there is no assurance that any derivatives
            strategy used by a Portfolio will succeed. A description of these
            and other derivative instruments that the Portfolios may use are
            described under "Investment Objectives and Policies" in the
            Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus
                                                                              26
<PAGE>

            each Portfolio will segregate assets determined to be liquid by
            PIMCO in accordance with procedures established by the Board of
            Trustees (or, as permitted by applicable regulation, enter into
            certain offsetting positions) to cover its obligations under
            derivative instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolios may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring a Portfolio to increase its investment in
Facilities  a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            a Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       Each Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Trans-      settlement date. This risk is in addition to the risk that the
actions     Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase a
            Portfolio's overall investment exposure. Typically, no income
            accrues on securities a Portfolio has committed to purchase prior
            to the time delivery of the securities is made, although a
            Portfolio may earn income on securities it has segregated to cover
            these positions.


   PIMCO Variable Insurance Trust
27
<PAGE>

Investment  Each Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, a Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, each
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       Each Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    Each Portfolio may invest up to 15% (10% in the case of the Money
Securities  Market Portfolio) of its net assets in illiquid securities.
            Certain illiquid securities may require pricing at fair value as
            determined in good faith under the supervision of the Board of
            Trustees. A portfolio manager may be subject to significant delays
            in disposing of illiquid securities, and transactions in illiquid
            securities may entail registration expenses and other transaction
            costs that are higher than those for transactions in liquid
            securities. The term "illiquid securities" for this purpose means
            securities that cannot be disposed of within seven days in the
            ordinary course of business at approximately the amount at which a
            Portfolio has valued the securities. Restricted securities, i.e.,
            securities subject to legal or contractual restrictions on resale,
            may be illiquid. However, some restricted securities (such as
            securities issued pursuant to Rule 144A under the Securities Act
            of 1933 and certain commercial paper) may be treated as liquid,
            although they may be less liquid than registered securities traded
            on established secondary markets.

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.


                                                                  Prospectus
                                                                              28
<PAGE>

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

   PIMCO Variable Insurance Trust
29
<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                  Prospectus
                                                                              30
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(b)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Money Market
 Administrative Class
 12/31/1999(a)         $ 1.00     $0.01        $ 0.00        $ 0.01      $(0.01)     $ 0.00        $ 0.00        $ 0.00
Total Return
 Administrative Class
 12/31/1999            $10.09     $0.58        $(0.64)(b)    $(0.06)     $(0.58)     $ 0.00        $ 0.00        $ 0.00
 12/31/1998(e)          10.00      0.56          0.28 (b)      0.84       (0.56)       0.00         (0.19)         0.00
Foreign Bond
 Administrative Class
 12/31/1999(f)         $10.00     $0.41        $(0.49)(b)    $(0.08)     $(0.41)     $ 0.00        $ 0.00        $(0.09)
StocksPLUS Growth and Income
 Administrative Class
 12/31/1999            $12.58     $0.76        $ 1.65 (b)    $ 2.41      $(0.61)     $(0.82)       $ 0.00        $ 0.00
 12/31/1998(e)          10.00      0.30          2.68 (b)      2.98       (0.29)      (0.11)         0.00          0.00
</TABLE>
- -------
(a) Commenced operations on September 30, 1999.
(b) Per share amounts based on average number of shares outstanding during the
    period.
(e) Commenced operations on December 31, 1997.
(f) Commenced operations on February 16, 1999.

   PIMCO Variable Insurance Trust
31
<PAGE>




<TABLE>
<CAPTION>
                                                                        Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of         Investment
 Return                    Value               End     Expenses to       Income to   Portfolio
   of          Total        End    Total    of Period    Average          Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets        Net Assets    Rate
- ----------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>              <C>          <C>


  $0.00       $(0.01)     $ 1.00    1.30 %   $  3,605     0.50%*(c)         5.14%*      N/A


  $0.00       $(0.58)     $ 9.45   (0.58)%   $  3,877     0.65% (d)         5.96%       102%
   0.00        (0.75)      10.09    8.61        3,259     0.65              5.55        139


  $0.00       $(0.50)     $ 9.42   (0.78)%   $  5,215     1.10%*(g)(h)      4.83%*      285%


  $0.00       $(1.43)     $13.56   19.85 %   $230,412     0.65%             5.69%        34%
   0.00        (0.40)      12.58   30.11       58,264     0.65              5.30         61
</TABLE>
- -------
*   Annualized.
(c) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 1.27%* for the
    period ended December 31, 1999.
(d) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.69% for the
    period ended December 31, 1999.
(g) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 1.25%* for the
    period ended December 31, 1999.
(h) Ratio of net expenses to average net assets excluding interest expense is
    0.90%.

                                                                  Prospectus
                                                                              32
<PAGE>

            Other Information


Performance The following table provides information concerning the historical
Information total return performance of the Institutional Class shares of
of          certain series of PIMCO Funds: Pacific Investment Management
Similar     Series ("PIMS"). Each PIMS series has investment objectives,
Funds       policies and strategies substantially similar to those of its
            respective PIMCO Variable Insurance Trust ("PVIT") Portfolio and
            is currently managed by the same portfolio manager. While the
            investment objectives and policies of each PIMS series and its
            respective PVIT Portfolio are similar, they are not identical and
            the performance of the PIMS series and the PVIT Portfolio will
            vary. The data is provided to illustrate the past performance of
            PIMCO in managing a substantially similar investment portfolio and
            does not represent the past performance of any of the PVIT
            Portfolios or the future performance of any PVIT Portfolio or its
            portfolio manager. Consequently, potential investors should not
            consider this performance data as an indication of the future
            performance of any PVIT Portfolio or of its portfolio manager.

            The performance data shown below reflects the operating expenses
            of the Institutional Class of the PIMS series. The operating
            expenses for the Institutional Class of the PIMS Foreign Bond Fund
            are lower than the operating expenses for the Institutional Class
            of the corresponding PVIT Portfolio. Furthermore, the operating
            expenses of the Institutional Class of each PIMS series in the
            table are lower than the operating expenses of each Administrative
            Class of the corresponding PVIT Portfolio. As such, performance
            would have been lower if the PVIT Portfolios' expenses were used.
            In addition, the PIMS series, unlike the Portfolios, are not sold
            to Separate Accounts to fund Variable Contracts. As a result, the
            performance results presented below do not take into account
            charges or deductions against a Separate Account or Variable
            Contract for cost of insurance charges, premium loads,
            administrative fees, maintenance fees, premium taxes, mortality
            and expense risk charges, or other charges that may be incurred
            under a Variable Contract for which the Portfolio serves as an
            underlying investment vehicle. By contrast, Variable Contract
            Owners with contract value allocated to the Portfolios will be
            subject to charges and expenses relating to the Variable Contracts
            and Separate Accounts.

            Each PIMS series' performance data shown below is calculated in
            accordance with standards prescribed by the SEC for the
            calculation of average annual total return information. The
            investment results of the PIMS series presented below are
            unaudited and are not intended to predict or suggest results that
            might be experienced by the PIMS series or the Portfolios. Share
            prices and investment returns will fluctuate reflecting market
            conditions, as well as changes in company-specific fundamentals of
            portfolio securities. The performance data for the benchmark
            indices identified below does not reflect the fees or expenses of
            the PIMS series or the Portfolios.


   PIMCO Variable Insurance Trust
33
<PAGE>

   Average Annual Total Return for Similar Series of PIMS Institutional Class
         and for Benchmark Indices for Periods Ended December 31, 1999

<TABLE>
<CAPTION>
                                                            Since   Inception
                                  1 Year  3 Years 5 Years Inception   Date
- -----------------------------------------------------------------------------
<S>                               <C>     <C>     <C>     <C>       <C>
PIMCO Money Market Fund/1/         4.90 %  5.19%    5.38%   4.72%     3/1/91
 Salomon 3-Month Treasury Bill/2/  4.73    5.01     5.20
PIMCO Foreign Bond Fund/3/         1.56    7.00    12.04    9.76     12/3/92
 J.P. Morgan Non-U.S. (Hedged)/4/  2.48    8.54    11.14
</TABLE>
- -------
/1/Prior to November 1995 and November 1999 the Money Market Fund was managed
   by a different portfolio manager.
/2/The Salomon 3-Month Treasury Bill Index is an unmanaged index representing
   monthly return equivalents of yield averages of the last 3 month Treasury
   Bill issues. It is not possible to invest directly in the index.
/3/Prior to July 1995, the Foreign Bond Fund was managed by a different
   portfolio manager.
/4/The J.P. Morgan Non-U.S. (Hedged) Index is an unmanaged market index
   representative of the total return performance in U.S. dollars of major non-
   U.S. bond markets. It is not possible to invest directly in the index.

                                                                  Prospectus
                                                                              34
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

   PIMCO Variable Insurance Trust
A-1
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

                                                                  Prospectus
                                                                             A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

   PIMCO Variable Insurance Trust
A-3
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

                                                                  Prospectus
                                                                             A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year. You may get free copies of any of these materials,
request other information about a Portfolio, or make shareholder inquires by
calling the Trust at 1-800-927-4648 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington, D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, which payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the investment company Act,
which is 811-8399.

[LOGO OF PIMCO FUNDS]

PIMCO FUNDS
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660
<PAGE>

PIMCO
Variable
Insurance
Trust

April 1, 2000

Share Class

Adm Administrative

PIMCO Funds Prospectus



- --------------------------------------------------------------------------------
INTERMEDIATE DURATION BOND PORTFOLIO
Total Return Bond Portfolio



This cover is not part of the Prospectus.                  [LOGO OF PIMCO FUNDS]
<PAGE>

            Prospectus


PIMCO       This Prospectus describes the Total Return Bond Portfolio (the
Variable    "Portfolio") which is a separate investment portfolio offered by
Insurance   the PIMCO Variable Insurance Trust (the "Trust"). The Portfolio
Trust       provides access to the professional investment management services
            offered by Pacific Investment Management Company ("PIMCO"). The
April 1,    investments made by the Portfolio at any given time are not
2000        expected to be the same as those made by other mutual funds for
            which PIMCO acts as investment adviser, including mutual funds
Share       with investment objectives and strategies similar to those of the
Class       Portfolio. Accordingly, the performance of the Portfolio can be
Adminis-    expected to vary from that of the other mutual funds.
trative

            This Prospectus explains what you should know about the Portfolio
            before you invest. Please read it carefully.

            Shares of the Portfolio currently are sold to segregated asset
            accounts ("Separate Accounts") of insurance companies that fund
            variable annuity contracts and variable life insurance policies
            ("Variable Contracts"). Assets in the Separate Account are
            invested in shares of the Portfolio in accordance with allocation
            instructions received from owners of the Variable Contracts
            ("Variable Contract Owners"). Variable Contract Owners do not deal
            directly with the Portfolio to purchase or redeem shares. The
            allocation rights of Variable Contract Owners are described in the
            accompanying Separate Account prospectus. Shares of the Portfolio
            also may be sold to qualified pension and retirement plans outside
            of the separate account context.

            This Prospectus should be read in conjunction with the prospectus
            of the Separate Account. Both prospectuses should be read
            carefully and retained for future reference.

            The Securities and Exchange Commission has not approved or
            disapproved these securities, or determined if this Prospectus is
            truthful or complete. Any representation to the contrary is a
            criminal offense.

   PIMCO Variable Insurance Trust
1
<PAGE>

            Table of Contents

<TABLE>
         <S>                                                               <C>
         Summary Information..............................................   3
         Portfolio Summary................................................   5
           Total Return Bond Portfolio....................................   5
         Summary of Principal Risks.......................................   7
         Management of the Portfolio......................................  10
         Investment Options...............................................  11
         Purchases and Redemptions........................................  12
         How Portfolio Shares are Priced..................................  13
         Tax Consequences.................................................  14
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  15
         Financial Highlights.............................................  25
         Appendix A--Description of Securities Ratings.................... A-1
</TABLE>

                                                                  Prospectus   2

<PAGE>

            Summary Information

The table below describes certain investment characteristics of the Portfolio.
Other important characteristics are described in the individual Portfolio
Summary beginning on page 5. Following the table are certain key concepts which
are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                       Non-U.S.
                                                                                       Dollar
                                                                     Credit            Denominated
                                 Main Investments          Duration  Quality(1)        Securities(2)
- ----------------------------------------------------------------------------------------------------
 <C>           <C>               <S>                       <C>       <C>               <C>
 Intermediate  Total Return Bond Intermediate maturity     3-6 years B to Aaa; max 10%     0-20%(3)
 Duration                        fixed income securities             below Baa
 Bond
 Portfolio
- ----------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  The Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)
Fixed       The Total Return Bond Portfolio is a "Fixed Income Portfolio". A
Income      Fixed Income Portfolio invests at least 65% of its assets in
Instruments "Fixed Income Instruments," which as used in this Prospectus
            includes:

            . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio   The Portfolio provides a broad range of investment choices. The
Descrip-    following summaries identify the Portfolio's investment objective,
tions,      principal investments and strategies, principal risks, performance
Perfor-     information and fees and expenses. A more detailed "Summary of
mance       Principal Risks" describing principal risks of investing in the
and Fees    Portfolio begins after the Portfolio Summary.

             It is possible to lose money on investments in the Portfolio.

             An investment in the Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.

                                                                  Prospectus   4

<PAGE>

            PIMCO Total Return Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Intermediate         B to Aaa; maximum
and           Seeks maximum          maturity fixed       10% below Baa
Strategies    total return,          income
              consistent with        securities           Dividend Frequency
              preservation of                             Declared daily and
              capital and            Average Portfolio    distributed monthly
              prudent                Duration
              investment             3-6 years
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a three- to six-year time frame based on
            PIMCO's forecast for interest rates.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Derivatives         .  Currency Risk
                 Risk                   Risk                .  Leveraging
              .  Credit Risk         .  Liquidity Risk         Risk
              .  Market Risk         .  Mortgage Risk       .  Management
              .  Issuer Risk         .  Foreign                Risk
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            Past performance is no guarantee of future results.


5  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Total Return Portfolio (continued)
<TABLE>
 <S>                                        <C>
             Calendar Year Total Returns -- Administrative Class
                                            Highest and Lowest Quarter Returns
                                            (for periods shown in the bar chart)
                   [BAR CHART]              ----------------------------
                                            Highest (3rd Qtr. '98)5.43%
                   1998   8.61%             ----------------------------
                   1999  -0.58%             Lowest (2nd Qtr. '99)(0.94%)

             Calendar Year End (through 12/31)
</TABLE>
            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                         1 Year  (12/31/97)
            -----------------------------------------------
         <S>                             <C>     <C>
         Administrative Class            (0.58%) 3.91%
            -----------------------------------------------
         Lehman Aggregate Bond Index(1)  (0.82%) 3.82%
            -----------------------------------------------
</TABLE>

            (1) The Lehman Brothers Aggregate Bond Index is an unmanaged index
                of investment grade, U.S. dollar-denominated fixed income
                securities of domestic issuers having a maturity greater than
                one year. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual
                                                   Portfolio                 Net Portfolio
                         Advisory Service Other    Operating    Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses     Reduction(2) Expenses
            ------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>          <C>          <C>
         Administrative  0.25%    0.15%   0.29%(1) 0.69%        (0.04%)      0.65%
            ------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.04%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class           Year 1             Year 3             Year 5             Year 10
            -----------------------------------------------------------------------------------
         <S>                   <C>                <C>                <C>                <C>
         Administrative        $66                $217               $380               $855
            -----------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   6
<PAGE>


            Summary of Principal Risks

            The value of your investment in the Portfolio changes with the
            values of the Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on the Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of the Portfolio are
            identified in the Portfolio Summary and are described in this
            section. The Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by the Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, its investments and the related risks. There is no
            guarantee that the Portfolio will be able to achieve its
            investment objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            A Portfolio with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tends to have the greatest exposure to
            liquidity risk.

7   PIMCO Variable Insurance Trust

<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolio may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolio typically uses derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolio may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    A Portfolio that invests directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies is subject to the risk that those currencies will
            decline in value relative to the U.S. dollar, or, in the case of
            hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary Fund, or
            by the imposition of currency controls or other political
            developments in the U.S. or abroad. As a result, a Portfolio's
            investments in foreign currency-denominated securities may reduce
            the returns of a Portfolio.

                                                                  Prospectus   8

<PAGE>

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolio securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  The Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and the individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

9   PIMCO Variable Insurance Trust

<PAGE>

            Management of the Portfolio

Investment  PIMCO serves as investment adviser and the administrator (serving
Adviser     in its capacity as administrator, the "Administrator") for the
and         Portfolio. Subject to the supervision of the Board of Trustees,
Adminis-    PIMCO is responsible for managing the investment activities of the
trator      Portfolio and the Portfolio's business affairs and other
            administrative matters.

             PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
            Beach, California 92660. Organized in 1971, PIMCO provides
            investment management and advisory services to private accounts of
            institutional and individual clients and to mutual funds. As of
            December 31, 1999, PIMCO had approximately $186 billion in assets
            under management.

Advisory    The Portfolio pays PIMCO fees in return for providing investment
Fees        advisory services. For the fiscal year ended December 31, 1999,
            the Portfolio paid monthly advisory fees to PIMCO at the following
            annual rates (stated as a percentage of the average daily net
            assets of the Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio                    Advisory Fees
            ---------------------------------------
         <S>                          <C>
         Total Return Bond Portfolio      0.40%
</TABLE>

             Effective April 1, 2000, the Portfolio pay monthly advisory fees
            to PIMCO at the following annual rates (stated as a percentage of
            the average daily net assets of the Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio
                                      Advisory Fees
            ---------------------------------------
         <S>                          <C>
         Total Return Bond Portfolio      0.25%
</TABLE>

Administra-  The Portfolio pays for the administrative services it requires
tive Fees    under a fee structure which is essentially fixed. Shareholders of
             the Portfolio pay an administrative fee to PIMCO, computed as a
             percentage of the Portfolio's assets attributable in the aggregate
             to that class of shares. PIMCO, in turn, provides or procures
             administrative services for shareholders and also bears the costs
             of various third-party services required by the Portfolio,
             including audit, custodial, portfolio accounting, legal, transfer
             agency and printing costs. The result of this fee structure is an
             expense level for shareholders of the Portfolio that, with limited
             exceptions, is precise and predictable under ordinary
             circumstances.

             For the fiscal year ended December 31, 1999, the Portfolio paid
            PIMCO monthly administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio                    Administrative Fees
            ---------------------------------------------
         <S>                          <C>
         Total Return Bond Portfolio         0.25%
</TABLE>

             Effective April 1, 2000, the Portfolio pays PIMCO monthly
            administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio                    Administrative Fees
            ---------------------------------------------
         <S>                          <C>
         Total Return Bond Portfolio         0.25%
</TABLE>

                                                                  Prospectus  10

<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by the Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolio, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio manager responsible for management of the Trust's
Manager     Portfolio, including his occupation for the past five years.

<TABLE>
<CAPTION>
                           Portfolio               Recent Professional
         Portfolio         Manager          Since  Experience
            -----------------------------------------------------------------

         <C>               <C>              <C>    <S>
         Total Return Bond William H. Gross 12/97* Managing Director, Chief
                                                   Investment Officer and a
                                                   founding partner of PIMCO.
</TABLE>



            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolio. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

11   PIMCO Variable Insurance Trust

<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of the Portfolio. The Plan allows the
            Portfolio to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with the Portfolio; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits the Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of the Portfolio's Administrative Class assets
            on an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolio may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolio to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolio.

             As of the date of this Prospectus, shares of the Portfolio are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolio currently does not foresee any disadvantages
            to Variable Contract Owners if the Portfolio serves as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolio served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            the insurance company with a separate account

                                                                  Prospectus  12

<PAGE>

            allocating assets to the Portfolio are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolio might be required
            to redeem the investment of one or more of its separate accounts
            from the Portfolio, which might force the Portfolio to sell
            securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolio or to reject any purchase order, in whole or in part, or
            to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolio to dispose of its
            securities or to determine fairly the value of its net assets, or
            during any other period as permitted by the SEC for the protection
            of investors. In the event that the Portfolio ceases offering its
            shares, any investments allocated to the Portfolio will, subject
            to any necessary regulatory approvals, be invested in another
            Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemptions of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolio to dispose of its
            securities or to determine fairly the value of its net assets, or
            during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by the Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of the Portfolio's Administrative
            Class shares is determined by dividing the total value of the
            Portfolio's investments and other assets attributable to that
            class, less any liabilities, by the total number of shares
            outstanding of that class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.


13 PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of the Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolio normally uses pricing data for
            domestic equity securities received shortly after the NYSE Close
            and does not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolio or its
            agents after the NAV has been calculated on a particular day will
            not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolio may value securities at fair value or
            estimate its value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

            Tax Consequences

            The Portfolio intends to qualify as a regulated investment company
            annually and to elect to be treated as a regulated investment
            company for federal income tax purposes. As such, the Portfolio
            generally will not pay federal income tax on the income and gains
            it pays as dividends to its shareholders. In order to avoid a 4%
            federal excise tax, the Portfolio intends to distribute each year
            substantially all of its net income and gains.

             The Portfolio also intends to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolio's Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus  14


<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolio described
            under the "Portfolio Summary" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolio from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolio. As with any mutual fund, investors in
            the Portfolio rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolio.

Securities  The Portfolio seeks maximum total return. The total return sought
Selection   by the Portfolio consists of both income earned on the Portfolio's
            investments and capital appreciation, if any, arising from
            increases in the market value of the Portfolio's holdings. Capital
            appreciation of fixed income securities generally results from
            decreases in market interest rates or improving credit
            fundamentals for a particular market sector or security.

             In selecting securities for the Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of the Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolio may invest include municipal lease obligations. The
            Portfolio may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   The Portfolio may invest all of its assets in mortgage- and asset-
Related     backed securities. Mortgage-related securities include mortgage
and Other   pass-through securities, collateralized mortgage obligations
Asset-      ("CMOs"), commercial mortgage-backed securities, mortgage dollar
Backed      rolls, CMO residuals, stripped mortgage-backed securities
Securities  ("SMBSs") and other securities that directly or indirectly
            represent a participation in, or are secured by and payable from,
            mortgage loans on real property.

15   PIMCO Variable Insurance Trust

<PAGE>

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolio may invest
            in other asset-backed securities that have been offered to
            investors.

Loan        The Portfolio may invest in fixed- and floating-rate loans, which
Participa-  investments generally will be in the form of loan participations
tions and   and assignments of portions of such loans. Participations and
Assignments assignments involve special types of risk, including credit risk,
            interest rate risk, liquidity risk, and the risks of being a
            lender. If a Portfolio purchases a participation, it may only be
            able to enforce its rights through the lender, and may assume the
            credit risk of the lender in addition to the borrower.

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

                                                                  Prospectus  16

<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

Variable    Variable and floating rate securities provide for a periodic
and         adjustment in the interest rate paid on the obligations. The
Floating    Portfolio may invest in floating rate debt instruments
Rate        ("floaters") and engage in credit spread trades. While floaters
Securities  provide a certain degree of protection against rises in interest
            rates, the Portfolio will participate in any declines in interest
            rates as well. The Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. The Portfolio may not invest more than 5%
            of its assets in any combination of inverse floater, interest
            only, or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      The Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, the Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible The Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

17   PIMCO Variable Insurance Trust

<PAGE>

             While a Fixed Income Portfolio intends to invest primarily in
            fixed income securities, it may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Foreign     Investing in the securities of issuers in any foreign country
(Non-       involves special risks and considerations not typically associated
U.S.)       with investing in U.S. companies. Shareholders should consider
Securities  carefully the substantial risks involved for a portfolio that
            invests in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             The Portfolio may invest in sovereign debt issued by governments,
            their agencies or instrumentalities, or other government-related
            entities. Holders of sovereign debt may be requested to
            participate in the rescheduling of such debt and to extend further
            loans to governmental entities. In addition, there is no
            bankruptcy proceeding by which defaulted sovereign debt may be
            collected.

              . Emerging Market Securities. A Portfolio that may invest in
            foreign securities, may invest up to 10% of its assets in
            securities of issuers based in countries with developing (or
            "emerging market") economies. Investing in emerging market
            securities imposes risks different from, or greater than, risks of
            investing in domestic securities or in foreign, developed
            countries. These risks include: smaller market capitalization of
            securities markets, which may suffer periods of relative
            illiquidity; significant price volatility; restrictions on foreign
            investment; possible repatriation of investment income and
            capital. In addition, foreign investors may be required to
            register the proceeds of sales; future economic or political
            crises could lead to price controls, forced mergers, expropriation
            or confiscatory taxation, seizure, nationalization, or creation of
            government monopolies. The currencies of emerging market countries
            may experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                Prospectus    18

<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             The Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolio's assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolio.

              . Foreign Currency Transactions. A Portfolio that invests in
            securities denominated in foreign currencies may enter into forward
            foreign currency exchange contracts and invest in foreign currency
            futures contracts and options on foreign currencies and futures. A
            forward foreign currency exchange contract, which involves an
            obligation to purchase or sell a specific currency at a future date
            at a price set at the time of the contract, reduces a Portfolio's
            exposure to changes in the value of the currency it will deliver and
            increases its exposure to changes in the value of the currency it
            will receive for the duration of the contract. The effect on the
            value of a Portfolio is similar to selling securities denominated in
            one currency and purchasing securities denominated in another
            currency. A contract to sell foreign currency would limit any
            potential gain which might be realized if the value of the hedged
            currency increases. A Portfolio may enter into these contracts to
            hedge against foreign exchange risk, to increase exposure to a
            foreign currency or to shift exposure to foreign currency
            fluctuations from one currency to another. Suitable hedging
            transactions may not be available in all circumstances and there can
            be no assurance that a Portfolio will engage in such transactions at
            any given time or from time to time. Also, such transactions may not
            be successful and may eliminate any chance for a Portfolio to
            benefit from favorable fluctuations in relevant foreign currencies.
            A Portfolio may use one currency (or a basket of currencies) to
            hedge against adverse changes in the value of another currency (or a
            basket of currencies) when exchange rates between the two currencies
            are positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations under
            forward foreign currency exchange contracts entered into for non-
            hedging purposes.

Repurchase  The Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


19   PIMCO Variable Insurance Trust

<PAGE>

Reverse     The Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             The Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, the Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. The Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives The Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. The Portfolio may invest
            all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolio may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             The Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolio.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus  20

<PAGE>

            the Portfolio will segregate assets determined to be liquid by
            PIMCO in accordance with procedures established by the Board of
            Trustees (or, as permitted by applicable regulation, enter into
            certain offsetting positions) to cover its obligations under
            derivative instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolio may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring the Portfolio to increase its investment
Facilities  in a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            the Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       The Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Trans-      settlement date. This risk is in addition to the risk that the
actions     Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase
            the Portfolio's overall investment exposure. Typically, no income
            accrues on securities the Portfolio has committed to purchase
            prior to the time delivery of the securities is made, although the
            Portfolio may earn income on securities it has segregated to cover
            these positions.


21   PIMCO Variable Insurance Trust

<PAGE>

Investment  The Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, the Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, the
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       The Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    The Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, the Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." The Portfolio may engage in frequent and active trading
            of portfolio securities to achieve its investment objective,
            particularly during periods of volatile market movements. High
            portfolio turnover (e.g., over 100%) involves correspondingly
            greater expenses to a Portfolio, including brokerage commissions
            or dealer mark-ups and other transaction costs on the sale of
            securities and reinvestments in other securities. Such sales may
            also result in realization of taxable capital gains, including
            short-term capital gains (which are generally taxed at ordinary
            income tax rates). The trading costs and tax effects associated
            with portfolio turnover may adversely effect the Portfolio's
            performance.


                                                                 Prospectus   22

<PAGE>

Temporary   For temporary or defensive purposes, the Portfolio may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of the Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolio may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolio may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolio to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolio.

23   PIMCO Variable Insurance Trust

<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                 Prospectus   24

<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Total Return
 Administrative Class
 12/31/1999            $10.09     $0.58        $(0.64)(a)    $(0.06)     $(0.58)      $0.00        $ 0.00         $0.00
 12/31/1998(c)          10.00      0.56          0.28 (a)      0.84       (0.56)       0.00         (0.19)         0.00
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(c) Commenced operations on December 31, 1997.

25    PIMCO Variable Insurance Trust

<PAGE>




<TABLE>
<CAPTION>
                                                                     Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of      Investment
 Return                    Value               End     Expenses to    Income to   Portfolio
   of          Total        End    Total    of Period    Average       Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets     Net Assets    Rate
- -------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>           <C>          <C>


  $0.00       $(0.58)     $ 9.45   (0.58)%    $3,877      0.65% (b)      5.96%       102%
   0.00        (0.75)      10.09    8.61       3,259      0.65           5.55        139
</TABLE>
- -------
(b) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.69% for the
    period ended December 31, 1999.

                                                                 Prospectus   26


<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

A-1   PIMCO Variable Insurance Trust

<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

                                                                 Prospectus  A-2

<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

A-3    PIMCO Variable Insurance Trust

<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

                                                                Prospectus   A-4

<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------

<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolio.  The SAI and the financial statements included in the Portfolio's
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes.  The Portfolio's annual report discusses the market conditions and
investment strategies that significantly affected the Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about the Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington, D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room.  You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov.  You
may get copies of this information, with payment of a duplication fee, by
writing the Public Reference Section of the Commission, Washington, D.C.
20549-0102.  You may need to refer to the Trust's file number under the
Investment Company Act, which is 811-8399.

[LOGO OF PIMCO FUNDS]

PIMCO Funds

840 Newport Center Drive
Suite 300
Newport Beach, CA 92660
<PAGE>

[LOGO]              PIMCO Funds Prospectus

PIMCO               ------------------------------------------------------------
Variable            INTERMEDIATE DURATION BOND PORTFOLIO
Insurance           Total Return Bond Portfolio II
Trust
                    ------------------------------------------------------------
April 1, 2000       LONG DURATION BOND PORTFOLIO
                    Long-Term U.S. Government Bond Portfolio
Share Class

Adm Administrative  This cover is not part of the Prospectus

                                                           [LOGO OF PIMCO FUNDS]

<PAGE>

            Prospectus


PIMCO       This Prospectus describes the Total Return Bond Portfolio II and
Variable    Long-Term U.S. Government Bond Portfolios (the "Portfolios") which
Insurance   are separate investment portfolios offered by the PIMCO Variable
Trust       Insurance Trust (the "Trust"). The Portfolios provide access to
            the professional investment management services offered by Pacific
April 1,    Investment Management Company ("PIMCO"). The investments made by
2000        the Portfolios at any given time are not expected to be the same
            as those made by other mutual funds for which PIMCO acts as
Share       investment adviser, including mutual funds with investment
Class       objectives and strategies similar to those of the Portfolios.
            Accordingly, the performance of the Portfolios can be expected to
Admini-     vary from that of the other mutual funds.
strative
            This Prospectus explains what you should know about the Portfolios
            before you invest. Please read it carefully.

            Shares of the Portfolios currently are sold to segregated asset
            accounts ("Separate Accounts") of insurance companies that fund
            variable annuity contracts and variable life insurance policies
            ("Variable Contracts"). Assets in the Separate Account are
            invested in shares of the Portfolios in accordance with allocation
            instructions received from owners of the Variable Contracts
            ("Variable Contract Owners"). Variable Contract Owners do not deal
            directly with the Portfolios to purchase or redeem shares. The
            allocation rights of Variable Contract Owners are described in the
            accompanying Separate Account prospectus. Shares of the Portfolios
            also may be sold to qualified pension and retirement plans outside
            of the separate account context.

            This Prospectus should be read in conjunction with the prospectus
            of the Separate Account. Both prospectuses should be read
            carefully and retained for future reference.

            The Securities and Exchange Commission has not approved or
            disapproved these securities, or determined if this Prospectus is
            truthful or complete. Any representation to the contrary is a
            criminal offense.

   PIMCO Variable Insurance Trust
1
<PAGE>

            Table of Contents

<TABLE>
         <S>                                                               <C>
         Summary Information..............................................   3
         Portfolio Summaries..............................................   5
           Total Return Bond Portfolio II.................................   5
           Long-Term U.S. Government Portfolio............................   7
         Summary of Principal Risks.......................................   9
         Management of the Portfolios.....................................  11
         Investment Options...............................................  12
         Purchases and Redemptions........................................  13
         How Portfolio Shares are Priced..................................  14
         Tax Consequences.................................................  15
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  16
         Financial Highlights.............................................  23
         Appendix A--Description of Securities Ratings.................... A-1
</TABLE>

                                                                  Prospectus
                                                                               2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                                      Non-U.S.
                                                                                                      Dollar
                                                                                           Credit     Denominated
                                    Main Investments           Duration                    Quality(1) Securities
- -----------------------------------------------------------------------------------------------------------------
 <C>           <C>                  <S>                        <C>                         <C>        <C>
 Intermediate  Total Return Bond II Intermediate maturity      3-6 years                   Baa to Aaa     0%
 Duration                           fixed income securities
 Bond                               with quality and non-
 Portfolio                          U.S. issuer restrictions
- -----------------------------------------------------------------------------------------------------------------
 Long          Long-Term            Long-term maturity fixed   (greater than or =) 8 years A to Aaa       0%
 Duration      U.S. Government      income securities
 Bond
 Portfolio
- -----------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)

Fixed       The "Fixed Income Portfolios" are the Total Return Bond II and the
Income      Long-Term U.S. Government Bond Portfolios. Each of the Fixed
Instruments Income Portfolios differs from the other primarily in the length
            of the Portfolio's duration or the proportion of its investments
            in certain types of fixed income securities. Each Fixed Income
            Portfolio invests at least 65% of its assets in "Fixed Income
            Instruments," which as used in this Prospectus includes:

            . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio   The Portfolios provide a broad range of investment choices. The
Descrip-    following summaries identify each Portfolio's investment
tions,      objective, principal investments and strategies, principal risks,
Performance performance information and fees and expenses. A more detailed
and Fees    "Summary of Principal Risks" describing principal risks of
            investing in the Portfolios begins after the Portfolio Summaries.

             It is possible to lose money on investments in the Portfolios.

             An investment in a Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.

                                                                  Prospectus
                                                                               4
<PAGE>

            PIMCO Total Return Portfolio II

- --------------------------------------------------------------------------------
Principal     Investment Objective  Portfolio Focus      Credit Quality
Investments   Seeks maximum         Intermediate         Baa to Aaa
and           total return,         maturity fixed
Strategies    consistent with       income               Dividend Frequency
              preservation of       securities           Declared daily and
              capital and                                distributed monthly
              prudent
              investment            Average Portfolio Duration
              management            3-6 years

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a three- to six-year time frame based on
            PIMCO's forecast for interest rates. The Portfolio may invest only
            in investment grade U.S. dollar denominated securities of U.S.
            issuers that are rated at least Baa by Moody's or BBB by S&P, or,
            if unrated, determined by PIMCO to be of comparable quality.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate      .  Issuer Risk        .  Leveraging Risk
                 Risk               .  Derivatives Risk   .  Liquidity Risk
              .  Credit Risk        .  Mortgage Risk      .  Management Risk
              .  Market Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.

   PIMCO Variable Insurance Trust
5
<PAGE>

            PIMCO Total Return Portfolio II (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment______None)

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.25%    0.15%   0.38%(1) 0.78%               (0.13%)      0.65%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.13%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class                         Year 1                                         Year 3
            --------------------------------------------------------------------------------------
         <S>                                 <C>                                            <C>
         Administrative                      $66                                            $236
            --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus
                                                                               6
<PAGE>

            PIMCO Long-Term U.S. Government Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Long-term            A to Aaa
and           Seeks maximum          maturity
Strategies    total return,          fixed income         Dividend Frequency
              consistent with        securities           Declared daily and
              preservation of                             distributed monthly
              capital and            Average Portfolio
              prudent                Duration
              investment             (greater than or
              management             =) 8 years

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of fixed income securities that are issued
            or guaranteed by the U.S. Government, its agencies or government-
            sponsored enterprises ("U.S. Government Securities"). Assets not
            invested in U.S. Government Securities may be invested in other
            types of Fixed Income Instruments. The Portfolio also may obtain
            exposure to U.S. Government Securities through the use of futures
            contracts (including related options) with respect to such
            securities, and options on such securities, when PIMCO deems it
            appropriate to do so. While PIMCO may invest in derivatives at any
            time it deems appropriate, it will generally do so when it
            believes that U.S. Government Securities are overvalued relative
            to derivative instruments. This Portfolio will normally have a
            minimum average portfolio duration of eight years. For point of
            reference, the dollar-weighted average portfolio maturity of the
            Portfolio is normally expected to be more than ten years.

             The Portfolio's investments in Fixed Income Instruments are
            limited to those of investment grade U.S. dollar-denominated
            securities of U.S. issuers that are rated at least A by Moody's or
            S&P, or, if unrated, determined by PIMCO to be of comparable
            quality. In addition, the Portfolio may only invest up to 10% of
            its assets in securities rated A by Moody's or S&P, and may only
            invest up to 25% of its assets in securities rated Aa by Moody's
            or AA by S&P.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage-backed securities. The Portfolio may
            lend its portfolio securities to brokers, dealers and other
            financial institutions to earn income. The Portfolio may seek to
            obtain market exposure to the securities in which it primarily
            invests by entering into a series of purchase and sale contracts
            or by using other investment techniques (such as buy backs or
            dollar rolls). The "total return" sought by the Portfolio consists
            of income earned on the Portfolio's investments, plus capital
            appreciation, if any, which generally arises from decreases in
            interest rates or improving credit fundamentals for a particular
            sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Issuer Risk         .  Leveraging Risk
                 Risk                .  Derivatives Risk    .  Management Risk
              .  Credit Risk         .  Mortgage Risk
              .  Market Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Perfor-     Performance information for this Portfolio is not provided because
mance       it has not been in operation for a full calendar year.
Infor-
mation

7  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Long-Term U.S. Government Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Administrative Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                   Total Annual                     Net Portfolio
                         Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class     Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            -------------------------------------------------------------------------------------
         <S>             <C>      <C>     <C>      <C>                 <C>          <C>
         Administrative  0.25%    0.15%   0.31%(1) 0.71%               (0.06%)          0.65%
            -------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" reflect a 0.25% administrative fee and 0.06%
                representing the Portfolio's organizational expenses as
                attributed to the class and pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Administrative Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.65% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Administrative Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class                         Year 1                                         Year 3
            --------------------------------------------------------------------------------------
         <S>                                 <C>                                            <C>
         Administrative                      $66                                            $221
            --------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus   8
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

   PIMCO Variable Insurance Trust
9
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolios may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

                                                                  Prospectus
                                                                              10
<PAGE>

            Management of the Portfolios

Investment  PIMCO serves as investment adviser and the administrator (serving
Adviser     in its capacity as administrator, the "Administrator") for the
and         Portfolios. Subject to the supervision of the Board of Trustees,
Admini-     PIMCO is responsible for managing the investment activities of the
strator     Portfolios and the Portfolios' business affairs and other
            administrative matters.

             PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
            Beach, California 92660. Organized in 1971, PIMCO provides
            investment management and advisory services to private accounts of
            institutional and individual clients and to mutual funds. As of
            December 31, 1999, PIMCO had approximately $186 billion in assets
            under management.

Advisory    Each Portfolio pays PIMCO fees in return for providing investment
Fees        advisory services. For the fiscal year ended December 31, 1999,
            the Portfolios paid monthly advisory fees to PIMCO at the
            following annual rates (stated as a percentage of the average
            daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio       Advisory Fees
         -----------------------------
         <S>             <C>
         All Portfolios      0.40%
</TABLE>

             Effective April 1, 2000, the Portfolios pay monthly advisory fees
            to PIMCO at the following annual rates (stated as a percentage of
            the average daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
         Portfolio       Advisory Fees
         -----------------------------
         <S>             <C>
         All Portfolios      0.25%
</TABLE>

Admini-  Each Portfolio pays for the administrative services it requires
strative under a fee structure which is essentially fixed. Shareholders of
Fees     each Portfolio pay an administrative fee to PIMCO, computed as a
         percentage of the Portfolio's assets attributable in the aggregate
         to that class of shares. PIMCO, in turn, provides or procures
         administrative services for shareholders and also bears the costs
         of various third-party services required by the Portfolios,
         including audit, custodial, portfolio accounting, legal, transfer
         agency and printing costs. The result of this fee structure is an
         expense level for shareholders of each Portfolio that, with
         limited exceptions, is precise and predictable under ordinary
         circumstances.

             For the fiscal year ended December 31, 1999, the Portfolios paid
            PIMCO monthly administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio       Administrative Fees
         -----------------------------------
         <S>             <C>
         All Portfolios         0.25%
</TABLE>

             Effective April 1, 2000, the Portfolios pay PIMCO monthly
            administrative fees at the following annual rates:

<TABLE>
<CAPTION>
         Portfolio       Administrative Fees
         -----------------------------------
         <S>             <C>
         All Portfolios         0.25%
</TABLE>

11 PIMCO Variable Insurance Trust
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

<TABLE>
<CAPTION>
                                        Portfolio              Recent Professional
         Portfolio                      Manager          Since Experience
            ---------------------------------------------------------------------------

         <C>                            <C>              <C>   <S>
         Total Return Bond II           William H. Gross 5/99* Managing Director, Chief
                                                               Investment Officer and a
                                                               founding partner of
                                                               PIMCO.




         Long-Term U.S. Government Bond James M. Keller  4/00  Executive Vice
                                                               President, PIMCO. He
                                                               joined PIMCO as a
                                                               Portfolio Manager in
                                                               1996, and has managed
                                                               fixed income accounts
                                                               for various
                                                               institutional clients
                                                               since that time.
</TABLE>
            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Administrative Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios. On that
            date, outstanding shares of the Trust were designated
            Administrative Class Shares. The Trust does not charge any sales
            charges (loads) or other fees in connection with purchases, sales
            (redemptions) or exchanges of Administrative Class shares.

                                                                  Prospectus
                                                                              12
<PAGE>

              . Service Fees--Administrative Class Shares. The Trust has
            adopted an Administrative Services Plan (the "Plan") for the
            Administrative Class shares of each Portfolio. The Plan allows the
            Portfolios to use its Administrative Class assets to reimburse
            financial intermediaries that provide services relating to
            Administrative Class shares. The services that will be provided
            under the Plan include, among other things, teleservicing support
            in connection with Portfolios; delivery of current Trust
            prospectuses and other shareholder communications; recordkeeping
            services; provision of support services, including providing
            information about the Trust and its Portfolios and answering
            questions concerning the Trust and its Portfolios, including
            questions respecting investors' interests in one or more
            Portfolios; provision and administration of insurance features for
            the benefit of investors in connection with the Portfolios;
            receiving, aggregating and forwarding purchase and redemption
            orders; processing dividend payments; issuing investor reports and
            transaction confirmations; providing subaccounting services;
            general account administration activities; and providing such
            similar services as the Trust may reasonably request to the extent
            the service provider is permitted to do so under applicable
            statutes, rules or regulation. The Plan also permits reimbursement
            for services in connection with the administration of plans or
            programs that use Administrative Class shares of the Portfolios as
            their funding medium and for related expenses.

             The Plan permits a Portfolio to make total reimbursements at an
            annual rate of 0.15% of the Portfolio's average daily net assets
            attributable to its Administrative Class shares. Because these
            fees are paid out of a Portfolio's Administrative Class assets on
            an ongoing basis, over time they will increase the cost of an
            investment in Administrative Class shares and may cost an investor
            more than other types of sales charges.

              . Arrangements with Service Agents. Administrative Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account

   PIMCO Variable Insurance Trust
13
<PAGE>

            allocating assets to the Portfolios are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolios might be
            required to redeem the investment of one or more of its separate
            accounts from the Portfolios, which might force the Portfolios to
            sell securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolios to dispose of
            their securities or to determine fairly the value of their net
            assets, or during any other period as permitted by the SEC for the
            protection of investors. In the event that a Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Administrative Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.


                                                                  Prospectus
                                                                              14
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

15 PIMCO Variable Insurance Trust
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  Most of the Portfolios in this prospectus seek maximum total
Selection   return. The total return sought by a Portfolio consists of both
            income earned on a Portfolio's investments and capital
            appreciation, if any, arising from increases in the market value
            of a Portfolio's holdings. Capital appreciation of fixed income
            securities generally results from decreases in market interest
            rates or improving credit fundamentals for a particular market
            sector or security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of a Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio may invest all of its assets in mortgage- and
Related     asset-backed securities. Mortgage-related securities include
and Other   mortgage pass-through securities, collateralized mortgage
Asset-      obligations ("CMOs"), commercial mortgage-backed securities,
Backed      mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities  securities ("SMBSs") and other securities that directly or
            indirectly represent a participation in, or are secured by and
            payable from, mortgage loans on real property.

                                                                  Prospectus
                                                                              16
<PAGE>

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolios may
            invest in other asset-backed securities that have been offered to
            investors.

Loan        Certain Portfolios may invest in fixed- and floating-rate loans,
Partici-    which investments generally will be in the form of loan
pations     participations and assignments of portions of such loans.
and         Participations and assignments involve special types of risk,
Assign-     including credit risk, interest rate risk, liquidity risk, and the
ments       risks of being a lender. If a Portfolio purchases a participation,
            it may only be able to enforce its rights through the lender, and
            may assume the credit risk of the lender in addition to the
            borrower.

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

   PIMCO Variable Insurance Trust
17
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

Variable    Variable and floating rate securities provide for a periodic
and         adjustment in the interest rate paid on the obligations. Each
Floating    Portfolio may invest in floating rate debt instruments
Rate        ("floaters") and engage in credit spread trades. While floaters
Securities  provide a certain degree of protection against rises in interest
            rates, a Portfolio will participate in any declines in interest
            rates as well. Each Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. A Portfolio may not invest more than 5% of
            its assets in any combination of inverse floater, interest only,
            or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      Each Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

                                                                  Prospectus
                                                                              18
<PAGE>

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.


Repurchase  Each Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. Each Portfolio may
            invest all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolios may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an

   PIMCO Variable Insurance Trust
19
<PAGE>

            understanding not only of the underlying instrument but also of
            the derivative itself, without the benefit of observing the
            performance of the derivative under all possible market
            conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk, each Portfolio
            will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees
            (or, as permitted by applicable regulation, enter into certain
            offsetting positions) to cover its obligations under derivative
            instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolios may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring a Portfolio to increase its investment in
Facilities  a company at a time when it might not otherwise decide to do so
            (including at a time when the

                                                                  Prospectus
                                                                              20
<PAGE>

            company's financial condition makes it unlikely that such amounts
            will be repaid). To the extent that a Portfolio is committed to
            advance additional funds, it will segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees in an amount sufficient to meet such
            commitments. Delayed funding loans and revolving credit facilities
            are subject to credit, interest rate and liquidity risk and the
            risks of being a lender.

When-       Each Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Trans-      settlement date. This risk is in addition to the risk that the
actions     Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase a
            Portfolio's overall investment exposure. Typically, no income
            accrues on securities a Portfolio has committed to purchase prior
            to the time delivery of the securities is made, although a
            Portfolio may earn income on securities it has segregated to cover
            these positions.

Investment  Each Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, a Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, each
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       Each Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    Each Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.

   PIMCO Variable Insurance Trust
21
<PAGE>

            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

                                                                  Prospectus
                                                                              22
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(a)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Total Return II
 Administrative Class
 12/31/1999(b)         $10.00     $0.32        $(0.18)(a)    $ 0.14      $(0.32)      $0.00         $0.00         $0.00
Long-Term U.S. Government
 Administrative Class
 12/31/1999(d)         $10.00     $0.36        $ 0.78 (a)    $(0.42)     $(0.36)      $0.00         $0.00         $0.00
</TABLE>
- -------
(a) Per share amounts based on average number of shares outstanding during the
    period.
(b) Commenced operations on May 28, 1999.
(d) Commenced operations on April 30, 1999.

   PIMCO Variable Insurance Trust
23
<PAGE>




<TABLE>
<CAPTION>
                                                                     Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of      Investment
 Return                    Value               End     Expenses to    Income to   Portfolio
   of          Total        End    Total    of Period    Average       Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets     Net Assets    Rate
- -------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>           <C>          <C>


  $0.00       $(0.32)      $9.82    1.41%     $5,128      0.65%*(c)      5.38%*      378%


  $0.00       $(0.36)      $9.22   (4.28)%    $7,173      0.65%*(e)      5.55%*      294%
</TABLE>
- -------
*   Annualized.
(c) If the investment manager had not reimbursed expenses, the ration of
    operating expenses to average net assets would have been 0.78%* for the
    period ended December 31, 1999.
(e) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.71%* for the
    period ended December 31, 1999.

                                                                   Prospectus
                                                                              24
<PAGE>

            Other Information


Performance The following table provides information concerning the historical
Information total return performance of the Institutional Class shares of
of          certain series of PIMCO Funds: Pacific Investment Management
Similar     Series ("PIMS"). Each PIMS series has investment objectives,
Funds       policies and strategies substantially similar to those of its
            respective PIMCO Variable Insurance Trust ("PVIT") Portfolio and
            is currently managed by the same portfolio manager. While the
            investment objectives and policies of each PIMS series and its
            respective PVIT Portfolio are similar, they are not identical and
            the performance of the PIMS series and the PVIT Portfolio will
            vary. The data is provided to illustrate the past performance of
            PIMCO in managing a substantially similar investment portfolio and
            does not represent the past performance of any of the PVIT
            Portfolios or the future performance of any PVIT Portfolio or its
            portfolio manager. Consequently, potential investors should not
            consider this performance data as an indication of the future
            performance of any PVIT Portfolio or of its portfolio manager.

            The performance data shown below reflects the operating expenses
            of the Institutional Class of each PIMS series. The operating
            expenses of the Institutional Class of each PIMS series in the
            table are lower than the operating expenses of each Administrative
            Class of the corresponding PVIT Portfolio. As such, performance
            would have been lower if the PVIT Portfolios' expenses were used.
            In addition, the PIMS series, unlike the Portfolios, are not sold
            to Separate Accounts to fund Variable Contracts. As a result, the
            performance results presented below do not take into account
            charges or deductions against a Separate Account or Variable
            Contract for cost of insurance charges, premium loads,
            administrative fees, maintenance fees, premium taxes, mortality
            and expense risk charges, or other charges that may be incurred
            under a Variable Contract for which the Portfolio serves as an
            underlying investment vehicle. By contrast, Variable Contract
            Owners with contract value allocated to the Portfolios will be
            subject to charges and expenses relating to the Variable Contracts
            and Separate Accounts.

            Each PIMS series' performance data shown below is calculated in
            accordance with standards prescribed by the SEC for the
            calculation of average annual total return information. The
            investment results of the PIMS series presented below are
            unaudited and are not intended to predict or suggest results that
            might be experienced by the PIMS series or the Portfolios. Share
            prices and investment returns will fluctuate reflecting market
            conditions, as well as changes in company-specific fundamentals of
            portfolio securities. The performance data for the benchmark
            indices identified below does not reflect the fees or expenses of
            the PIMS series or the Portfolios.

   Average Annual Total Return for Similar Series of PIMS Institutional Class
         and for Benchmark Indices for Periods Ended December 31, 1999

<TABLE>
<CAPTION>
                                                             Since   Inception
                                   1 Year  3 Years 5 Years Inception   Date
- ------------------------------------------------------------------------------
<S>                                <C>     <C>     <C>     <C>       <C>
PIMCO Total Return Fund II         (1.07)   6.06    8.07      7.25   12/30/91
 Lehman Brothers Aggregate Bond/1/ (0.82)   5.73    7.73
PIMCO Long-Term U.S. Government
 Fund/2/                           (7.99)   6.27    9.72     10.35     7/1/91
 Lehman Long-Term Treasury/3/      (8.74)   6.03    9.08
</TABLE>
- -------
/1/The Lehman Brothers Aggregate Bond Index is an unmanaged index of investment
  grade, U.S. dollar-denominated fixed income securities of domestic issuers
  having a maturity greater than one year. It is not possible to invest
  directly in the index.
/2/Prior to July 1997 and April 2000 the Long-Term U.S. Government Fund was
  managed by different portfolio managers.
/3/The Lehman Long-Term Treasury Index is an unmanaged index of U.S. Treasury
  issues with maturities greater than 10 years. It is not possible to invest
  directly in the index.

   PIMCO Variable Insurance Trust
25
<PAGE>


            Appendix A
            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

                                                                  Prospectus
                                                                             A-1
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

   PIMCO Variable Insurance Trust
A-2
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

                                                                  Prospectus
                                                                             A-3
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

   PIMCO Variable Insurance Trust
A-4
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington, D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.

[LOGO OF PIMCO FUNDS]

PIMCO Funds
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660
<PAGE>

[LOGO]             PIMCO Funds Prospectus

PIMCO              -------------------------------------------------------------
Variable           SHORT DURATION BOND PORTFOLIO
Insurance          Short-Term Bond Portfolio
Trust

April 1, 2000      -------------------------------------------------------------
                   INTERMEDIATE DURATION BOND PORTFOLIO
Share Class        Total Return Bond Portfolio

Ins Institutional  -------------------------------------------------------------
                   STOCK PORTFOLIO
                   StocksPLUS Growth and Income Portfolio

                   This cover is not part of the Prospectus
                                                           [LOGO OF PIMCO FUNDS]
<PAGE>

            Prospectus


PIMCO       This Prospectus describes 3 separate investment portfolios (the
Variable    "Portfolios"), offered by the PIMCO Variable Insurance Trust (the
Insurance   "Trust"). The Portfolios provide access to the professional
Trust       investment management services offered by Pacific Investment
            Management Company ("PIMCO"). The investments made by the
April 1,    Portfolios at any given time are not expected to be the same as
2000        those made by other mutual funds for which PIMCO acts as
            investment adviser, including mutual funds with investment
Share       objectives and strategies similar to those of the Portfolios.
Class       Accordingly, the performance of the Portfolios can be expected to
            vary from that of the other mutual funds.
Institu-
tional
            This Prospectus explains what you should know about the Portfolios
            before you invest. Please read it carefully.

            Shares of the Portfolios currently are sold to segregated asset
            accounts ("Separate Accounts") of insurance companies that fund
            variable annuity contracts and variable life insurance policies
            ("Variable Contracts"). Assets in the Separate Account are
            invested in shares of the Portfolios in accordance with allocation
            instructions received from owners of the Variable Contracts
            ("Variable Contract Owners"). Variable Contract Owners do not deal
            directly with the Portfolios to purchase or redeem shares. The
            allocation rights of Variable Contract Owners are described in the
            accompanying Separate Account prospectus. Shares of the Portfolios
            also may be sold to qualified pension and retirement plans outside
            of the separate account context.

            This Prospectus should be read in conjunction with the prospectus
            of the Separate Account. Both prospectuses should be read
            carefully and retained for future reference.

            The Securities and Exchange Commission has not approved or
            disapproved these securities, or determined if this Prospectus is
            truthful or complete. Any representation to the contrary is a
            criminal offense.

   PIMCO Variable Insurance Trust
1
<PAGE>

            Table of Contents

<TABLE>
         <S>                                                               <C>
         Summary Information..............................................   3
         Portfolio Summaries..............................................   5
           Short-Term Bond Portfolio......................................   5
           Total Return Bond Portfolio....................................   7
           StocksPLUS Growth and Income Portfolio.........................   9
         Summary of Principal Risks.......................................  11
         Management of the Portfolios.....................................  14
         Investment Options...............................................  15
         Purchases and Redemptions........................................  16
         How Portfolio Shares are Priced..................................  17
         Tax Consequences.................................................  18
         Characteristics and Risks of Securities and Investment
          Techniques......................................................  19
         Financial Highlights.............................................  29
         Appendix A--Description of Securities Ratings.................... A-1
</TABLE>

                                                                  Prospectus
                                                                               2
<PAGE>

            Summary Information

The table below compares certain investment characteristics of the Portfolios.
Other important characteristics are described in the individual Portfolio
Summaries beginning on page 5. Following the table are certain key concepts
which are used throughout the Prospectus.

<TABLE>
<CAPTION>
                                                                                                   Non-U.S.
                                                                                                   Dollar
                                                                                 Credit            Denominated
                                            Main Investments           Duration  Quality(1)        Securities(2)
- ----------------------------------------------------------------------------------------------------------------
 <C>           <C>                          <S>                        <C>       <C>               <C>
 Short         Short-Term Bond              Money market instruments   0-1 year  B to Aaa; max 10%   0-5%(3)
 Duration                                   and short maturity fixed             below Baa
 Bond                                       income securities
 Portfolio
- ----------------------------------------------------------------------------------------------------------------
 Intermediate  Total Return Bond            Intermediate maturity      3-6 years B to Aaa; max 10%   0-20%(3)
 Duration                                   fixed income securities              below Baa
 Bond
 Portfolio
- ----------------------------------------------------------------------------------------------------------------
 Stock         StocksPLUS Growth and Income S&P 500 stock index        0-1 year  B to Aaa; max       0-20%(3)
 Portfolio                                  derivatives backed by a              10% below Baa
                                            portfolio of short-term
                                            fixed-income securities
- ----------------------------------------------------------------------------------------------------------------
</TABLE>
(1)  As rated by Moody's Investors Service, Inc., or equivalently rated by
     Standard & Poor's Ratings Services, or if unrated, determined by PIMCO to
     be of comparable quality.
(2)  Each Portfolio may invest beyond this limit in U.S. dollar-denominated
     securities.
(3)  The percentage limitation relates to non-U.S. dollar-denominated
     securities.

3  PIMCO Variable Insurance Trust
<PAGE>

            Summary Information (continued)

Fixed       The "Fixed Income Portfolios" are the Short-Term Bond and the
Income      Total Return Bond Portfolios. Each of the Fixed Income Portfolios
Instruments differs from the other primarily in the length of the Portfolio's
            duration or the proportion of its investments in certain types of
            fixed income securities. Each Fixed Income Portfolio invests at
            least 65% of its assets in "Fixed Income Instruments," which as
            used in this Prospectus includes:

            . securities issued or guaranteed by the U.S. Government, its
              agencies or government-sponsored enterprises ("U.S. Government
              Securities");
            . corporate debt securities of U.S. and non-U.S. issuers,
              including convertible securities and corporate commercial paper;
            . mortgage-backed and other asset-backed securities;
            . inflation-indexed bonds issued both by governments and
              corporations;
            . structured notes, including hybrid or "indexed" securities,
              event-linked bonds and loan participations;
            . delayed funding loans and revolving credit facilities;
            . bank certificates of deposit, fixed time deposits and bankers'
              acceptances;
            . repurchase agreements and reverse repurchase agreements;
            . debt securities issued by states or local governments and their
              agencies, authorities and other instrumentalities;
            . obligations of non-U.S. governments or their subdivisions,
              agencies and instrumentalities; and
            . obligations of international agencies or supranational entities.

Duration    Duration is a measure of the expected life of a fixed income
            security that is used to determine the sensitivity of a security's
            price to changes in interest rates. The longer a security's
            duration, the more sensitive it will be to changes in interest
            rates. Similarly, a Portfolio with a longer average portfolio
            duration will be more sensitive to changes in interest rates than
            a Portfolio with a shorter average portfolio duration.

Credit      In this Prospectus, references are made to credit ratings of debt
Ratings     securities which measure an issuer's expected ability to pay
            principal and interest on time. Credit ratings are determined by
            rating organizations, such as Standard & Poor's Rating Service
            ("S&P") or Moody's Investors Service, Inc. ("Moody's"). The
            following terms are generally used to describe the credit quality
            of debt securities depending on the security's credit rating or,
            if unrated, credit quality as determined by PIMCO:

            . high quality
            . investment grade
            . below investment grade ("high yield securities" or "junk bonds")

             For a further description of credit ratings, see "Appendix A--
            Description of Securities Ratings."

Portfolio   The Portfolios provide a broad range of investment choices. The
Descrip-    following summaries identify each Portfolio's investment
tions,      objective, principal investments and strategies, principal risks,
Performance performance information and fees and expenses. A more detailed
and Fees    "Summary of Principal Risks" describing principal risks of
            investing in the Portfolios begins after the Portfolio Summaries.

             It is possible to lose money on investments in the Portfolios.

             An investment in a Portfolio is not a deposit of a bank and is
            not guaranteed or insured by the Federal Deposit Insurance
            Corporation or any other government agency.

                                                                  Prospectus
                                                                               4
<PAGE>

            PIMCO Short-Term Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Money market         B to Aaa; maximum
and           Seeks maximum          instruments and      10% below Baa
Strategies    current income,        short maturity
              consistent with        fixed income         Dividend Frequency
              preservation of        securities           Declared daily and
              capital and daily                           distributed monthly
              liquidity              Average Portfolio
                                     Duration
                                     0-1 year

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio will
            vary based on PIMCO's forecast for interest rates and will
            normally not exceed one year. For point of reference, the dollar-
            weighted average portfolio maturity of this Portfolio is normally
            not expected to exceed three years.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P, or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 5% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls).

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Issuer Risk         .  Leveraging
                 Risk                .  Derivatives            Risk
              .  Credit Risk            Risk                .  Management
              .  Market Risk         .  Mortgage Risk          Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance Performance information for this Portfolio is not provided because
Information it has not been in operation for a full calendar year.
5
   PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Short-Term Portfolio (continued)

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Institutional Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment) None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
         <S>            <C>      <C>     <C>      <C>                 <C>          <C>
                                                  Total Annual                     Net Portfolio
                        Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class    Fees     Fees    Expenses Expenses            Reduction(2) Expenses
            ------------------------------------------------------------------------------------
         Institutional  0.25%    None    0.21%(1) 0.46%               (0.01%)      0.45%
            ------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses", which are based on estimated amounts for the
                initial fiscal year of the class, reflect a 0.20%
                administrative fee and 0.01% representing the class' estimated
                pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Institutional Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.45% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Institutional Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
         <S>                                <C>                                            <C>
         Share Class                        Year 1                                         Year 3
            -------------------------------------------------------------------------------------
         Institutional                      $46                                            $147
            -------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus
                                                                               6
<PAGE>

            PIMCO Total Return Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              Intermediate         B to Aaa; maximum
and           Seeks maximum          maturity fixed       10% below Baa
Strategies    total return,          income
              consistent with        securities           Dividend Frequency
              preservation of                             Declared daily and
              capital and            Average Portfolio    distributed monthly
              prudent                Duration
              investment             3-6 years
              management

            The Portfolio seeks to achieve its investment objective by
            investing under normal circumstances at least 65% of its assets in
            a diversified portfolio of Fixed Income Instruments of varying
            maturities. The average portfolio duration of this Portfolio
            normally varies within a three- to six-year time frame based on
            PIMCO's forecast for interest rates.

             The Portfolio invests primarily in investment grade debt
            securities, but may invest up to 10% of its assets in high yield
            securities ("junk bonds") rated B or higher by Moody's or S&P or,
            if unrated, determined by PIMCO to be of comparable quality. The
            Portfolio may invest up to 20% of its assets in securities
            denominated in foreign currencies, and may invest beyond this
            limit in U.S. dollar-denominated securities of foreign issuers.
            The Portfolio will normally hedge at least 75% of its exposure to
            foreign currency to reduce the risk of loss due to fluctuations in
            currency exchange rates.

             The Portfolio may invest all of its assets in derivative
            instruments, such as options, futures contracts or swap
            agreements, or in mortgage- or asset-backed securities. The
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income. The Portfolio may
            seek to obtain market exposure to the securities in which it
            primarily invests by entering into a series of purchase and sale
            contracts or by using other investment techniques (such as buy
            backs or dollar rolls). The "total return" sought by the Portfolio
            consists of income earned on the Portfolio's investments, plus
            capital appreciation, if any, which generally arises from
            decreases in interest rates or improving credit fundamentals for a
            particular sector or security.

- --------------------------------------------------------------------------------
Principal   Among the principal risks of investing in the Portfolio, which
Risks       could adversely affect its net asset value, yield and total
            return, are:

              .  Interest Rate       .  Derivatives         .  Currency Risk
                 Risk                   Risk                .  Leveraging
              .  Credit Risk         .  Liquidity Risk         Risk
              .  Market Risk         .  Mortgage Risk       .  Management
              .  Issuer Risk         .  Foreign                Risk
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            No performance information has been provided for Institutional
            Class shares because they were not offered prior to the date of
            this Prospectus. For the same periods, Institutional Class shares
            would have had higher annual returns than Administrative Class
            shares, even though they are invested in the same portfolio of
            securities, because Institutional Class shares pay lower total
            annual operating expenses. Past performance is no guarantee of
            future results.

7
   PIMCO Variable Insurance Trust
<PAGE>

            PIMCO Total Return Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

                                  [GRAPH]
                               1998    8.61%
                               1999   -0.58%

                  Calendar Year End (through 12/31)

Highest and Lowest Quarter Returns
(for periods shown in the bar chart)
- ------------------------------------
Highest (3rd Qtr. '98)        5.43%
- -----------------------------------
Lowest (2nd Qtr. '99)        (0.94%)

            Average Annual Total Returns (for periods ended 12/31/99)

<TABLE>
<CAPTION>
                                                 Portfolio
                                                 Inception
                                         1 Year  (12/31/97)
         --------------------------------------------------
         <S>                             <C>     <C>
         Administrative Class            (0.58%) 3.91%
         --------------------------------------------------
         Lehman Aggregate Bond Index(1)  (0.82%) 3.82%
         --------------------------------------------------
</TABLE>

            (1) The Lehman Brothers Aggregate Bond Index is an unmanaged index
                of investment grade, U.S. dollar-denominated fixed income
                securities of domestic issuers having a maturity greater than
                one year. It is not possible to invest directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Institutional Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                  Total Annual
                                                  Portfolio                 Net Portfolio
                        Advisory Service Other    Operating    Expense      Operating
         Share Class    Fees     Fees    Expenses Expenses     Reduction(2) Expenses
         --------------------------------------------------------------------------------
         <S>            <C>      <C>     <C>      <C>          <C>          <C>
         Institutional  0.25%    None    0.26%(1) 0.51%        (0.01%)      0.50%
         --------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses", which are based on estimated amounts for the
                initial fiscal year of the class, reflect a 0.25%
                administrative fee and 0.01% representing the class' estimated
                pro rata Trustees' fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operating expenses for the Institutional Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.50% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Institutional Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class          Year 1             Year 3             Year 5             Year 10
            ----------------------------------------------------------------------------------
         <S>                  <C>                <C>                <C>                <C>
         Institutional        $51                $163               $284               $640
            ----------------------------------------------------------------------------------
</TABLE>
                                                                               8
                                                                  Prospectus
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio

- --------------------------------------------------------------------------------
Principal     Investment             Portfolio Focus      Credit Quality
Investments   Objective              S&P 500 stock        B to Aaa; maximum
and           Seeks total            index derivatives    10% below Baa
Strategies    return which           backed by a
              exceeds that of        portfolio of         Dividend
              the S&P 500            short-term fixed     Frequency
                                     income securities    Declared and
                                                          distributed
                                     Average Portfolio    quarterly
                                     Duration
                                     0-1 year

            The Portfolio seeks to exceed the total return of the S&P 500 by
            investing under normal circumstances substantially all of its
            assets in S&P 500 derivatives, backed by a portfolio of Fixed
            Income Instruments. The Portfolio may invest in common stocks,
            options, futures, options on futures and swaps. The Portfolio uses
            S&P 500 derivatives in addition to or in place of S&P 500 stocks
            to attempt to equal or exceed the performance of the S&P 500. The
            value of S&P 500 derivatives closely track changes in the value of
            the index. However, S&P 500 derivatives may be purchased with a
            fraction of the assets that would be needed to purchase the equity
            securities directly, so that the remainder of the assets may be
            invested in Fixed Income Instruments. PIMCO actively manages the
            fixed income assets held by the Portfolio with a view toward
            enhancing the Portfolio's total return, subject to an overall
            portfolio duration which is normally not expected to exceed one
            year.

             The S&P 500 is composed of 500 selected common stocks that
            represent approximately two-thirds of the total market value of
            all U.S. common stocks. The Portfolio is neither sponsored by nor
            affiliated with S&P. The Portfolio seeks to remain invested in S&P
            500 derivatives or S&P 500 stocks even when the S&P 500 is
            declining.

             Though the Portfolio does not normally invest directly in S&P 500
            securities, when S&P 500 derivatives appear to be overvalued
            relative to the S&P 500, the Portfolio may invest all of its
            assets in a "basket" of S&P 500 stocks. Individual stocks are
            selected based on an analysis of the historical correlation
            between the return of every S&P 500 stock and the return on the
            S&P 500 itself. PIMCO may employ fundamental analysis of factors
            such as earnings and earnings growth, price to earnings ratio,
            dividend growth, and cash flows to choose among stocks that
            satisfy the correlation tests. Stocks chosen for the Portfolio are
            not limited to those with any particular weighting in the S&P 500.
            The Portfolio may also invest in exchange traded funds based on
            the S&P 500, such as Standard & Poor's Depositary Receipt.

             Assets not invested in equity securities or derivatives may be
            invested in Fixed Income Instruments. The Portfolio may invest up
            to 10% of its assets in high yield securities ("junk bonds") rated
            B or higher by Moody's or S&P, or, if unrated, determined by PIMCO
            to be of comparable quality. The Portfolio may invest up to 20% of
            its assets in securities denominated in foreign currencies and may
            invest beyond this limit in U.S. dollar denominated securities of
            foreign issuers. The Portfolio will normally hedge at least 75% of
            its exposure to foreign currency to reduce the risk of loss due to
            fluctuations in currency exchange rates. In addition, the
            Portfolio may lend its portfolio securities to brokers, dealers
            and other financial institutions to earn income.

- --------------------------------------------------------------------------------
Principal   Under certain conditions, generally in a market where the value of
Risks       both S&P 500 derivatives and fixed income securities are
            declining, the Portfolio may experience greater losses than would
            be the case if it invested directly in a portfolio of S&P 500
            stocks. Among the principal risks of investing in the Portfolio,
            which could adversely affect its net asset value, yield and total
            return, are:

              . Market Risk          . Interest Rate        . Mortgage Risk
              . Issuer Risk             Risk                . Leveraging Risk
              . Derivatives Risk     . Liquidity Risk       . Management Risk
              . Credit Risk          . Foreign
                                        Investment
                                        Risk

            Please see "Summary of Principal Risks" following the Portfolio
            Summaries for a description of these and other risks of investing
            in the Portfolio.
                                     . Currency Risk

- --------------------------------------------------------------------------------
Performance The top of the next page shows summary performance information for
Information the Portfolio in a bar chart and an Average Annual Total Returns
            table. The information provides some indication of the risks of
            investing in the Portfolio by showing changes in its performance
            from year to year and by showing how the Portfolio's average
            annual returns compare with the returns of a broad-based
            securities market index. The bar chart and the information to its
            right show performance of the Portfolio's Administrative Class
            Shares. The bar chart and table do not reflect Variable Contract
            fees and expenses. If they did, performance would have been lower.
            No performance information has been provided for Institutional
            Class shares because they were not offered prior to the date of
            this Prospectus. For the same periods, Institutional Class shares
            would have had higher annual returns than Administrative Class
            shares, even though they are invested in the same portfolio of
            securities, because Institutional Class shares pay lower total
            annual operating expenses. Past performance is no guarantee of
            future results.

9  PIMCO Variable Insurance Trust
<PAGE>

            PIMCO StocksPLUS Growth and Income Portfolio (continued)

            Calendar Year Total Returns -- Administrative Class

                                   [GRAPH]

                               1998     30.11%
                               1999     19.85%

                  Calendar Year End (through 12/31)

Highest and Lowest Quarter Returns
(for periods shown in the bar chart)
- ------------------------------------
Highest (4th Qtr. '98)        21.95%
- ------------------------------------
Lowest (3rd Qtr. '98)         -8.82%

            Average Annual Total Returns (for periods ended 12/31/99)
<TABLE>
<CAPTION>
                                                                                   Portfolio
                                                                                   Inception
                                              1 Year                               (12/31/97)
         ------------------------------------------------------------------------------------
         <S>                                  <C>                                  <C>
         Administrative Class                 19.85%                               24.87%
         ------------------------------------------------------------------------------------
         S&P 500 Index(1)                     21.04%                               24.75%
         ------------------------------------------------------------------------------------
</TABLE>

            (1) The Standard & Poor's 500 Composite Stock Price Index is an
                unmanaged index of common stocks. It is not possible to invest
                directly in the index.

- --------------------------------------------------------------------------------
Fees and    These tables describe the fees and expenses you may pay if you buy
Expenses    and hold Institutional Class shares of the Portfolio:
of the
Portfolio   Shareholder Fees (fees paid directly from your investment)     None

            Annual Portfolio Operating Expenses (expenses that are deducted
            from Portfolio assets)

<TABLE>
<CAPTION>
                                                  Total Annual                     Net Portfolio
                        Advisory Service Other    Portfolio Operating Expense      Operating
         Share Class    Fees     Fees    Expenses Expenses            Reduction(2) Expenses
         ---------------------------------------------------------------------------------------
         <S>            <C>      <C>     <C>      <C>                 <C>          <C>
         Institutional  0.40%    None    0.11%(1) 0.51%               (0.01%)      0.50%
         ---------------------------------------------------------------------------------------
</TABLE>

            (1) "Other Expenses" which are based on estimated amounts for the
                initial fiscal year of the class, reflect a 0.10%
                administrative fee and 0.01% representing the class' estimated
                pro rata Trustee's fees.
            (2) PIMCO has contractually agreed to reduce total annual
                portfolio operation expenses for the Institutional Class
                shares to the extent they would exceed, due to the payment of
                organizational expenses and Trustees' fees, 0.50% of average
                daily net assets. Under the Expense Limitation Agreement,
                PIMCO may recoup these waivers and reimbursements in future
                periods, not exceeding three years, provided total expenses,
                including such recoupment, do not exceed the annual expense
                limit.

            Examples. The Examples are intended to help you compare the cost
            of investing in Institutional Class shares of the Portfolio with
            the costs of investing in other mutual funds. The Examples assume
            that you invest $10,000 in the noted class of shares for the time
            periods indicated, and then redeem all your shares at the end of
            those periods. The Examples also assume that your investment has a
            5% return each year, the reinvestment of all dividends and
            distributions, and that the Portfolio's operating expenses remain
            the same. Although your actual costs may be higher or lower, the
            Examples show what your costs would be based on these assumptions.

<TABLE>
<CAPTION>
         Share Class          Year 1             Year 3             Year 5             Year 10
         -------------------------------------------------------------------------------------
         <S>                  <C>                <C>                <C>                <C>
         Institutional        $51                $163               $284               $640
         -------------------------------------------------------------------------------------
</TABLE>

                                                                  Prospectus  10
<PAGE>


            Summary of Principal Risks

            The value of your investment in a Portfolio changes with the
            values of that Portfolio's investments. Many factors can affect
            those values. The factors that are most likely to have a material
            effect on a particular Portfolio's portfolio as a whole are called
            "principal risks." The principal risks of each Portfolio are
            identified in the Portfolio Summaries and are described in this
            section. Each Portfolio may be subject to additional principal
            risks and risks other than those described below because the types
            of investments made by a Portfolio can change over time.
            Securities and investment techniques mentioned in this summary and
            described in greater detail under "Characteristics and Risks of
            Securities and Investment Techniques" appear in bold type. That
            section and "Investment Objectives and Policies" in the Statement
            of Additional Information also include more information about the
            Portfolio, their investments and the related risks. There is no
            guarantee that a Portfolio will be able to achieve its investment
            objective.

Interest    As interest rates rise, the value of fixed income securities held
Rate Risk   by a Portfolio are likely to decrease. Securities with longer
            durations tend to be more sensitive to changes in interest rates,
            usually making them more volatile than securities with shorter
            durations.

Credit      A Portfolio could lose money if the issuer or guarantor of a fixed
Risk        income security, or the counterparty to a derivatives contract,
            repurchase agreement or a loan of portfolio securities, is unable
            or unwilling to make timely principal and/or interest payments, or
            to otherwise honor its obligations. Securities are subject to
            varying degrees of credit risk, which are often reflected in
            credit ratings. Municipal bonds are subject to the risk that
            litigation, legislation or other political events, local business
            or economic conditions, or the bankruptcy of the issuer could have
            a significant effect on an issuer's ability to make payments of
            principal and/or interest.

Market      The market price of securities owned by a Portfolio may go up or
Risk        down, sometimes rapidly or unpredictably. Securities may decline
            in value due to factors affecting securities markets generally or
            particular industries represented in the securities markets. The
            value of a security may decline due to general market conditions
            which are not specifically related to a particular company, such
            as real or perceived adverse economic conditions, changes in the
            general outlook for corporate earnings, changes in interest or
            currency rates or adverse investor sentiment generally. They may
            also decline due to factors which affect a particular industry or
            industries, such as labor shortages or increased production costs
            and competitive conditions within an industry. Equity securities
            generally have greater price volatility than fixed income
            securities.

Issuer      The value of a security may decline for a number of reasons which
Risk        directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

Liquidity   Liquidity risk exists when particular investments are difficult to
Risk        purchase or sell. A Portfolio's investments in illiquid securities
            may reduce the returns of the Portfolio because it may be unable
            to sell the illiquid securities at an advantageous time or price.
            Portfolios with principal investment strategies that involve
            foreign securities, derivatives or securities with substantial
            market and/or credit risk tend to have the greatest exposure to
            liquidity risk.

   PIMCO Variable Insurance Trust
11
<PAGE>

Derivatives Derivatives are financial contracts whose value depends on, or is
Risk        derived from, the value of an underlying asset, reference rate or
            index. The various derivative instruments that the Portfolios may
            use are referenced under "Characteristics and Risks of Securities
            and Investment Techniques--Derivatives" in this Prospectus and
            described in more detail under "Investment Objectives and
            Policies" in the Statement of Additional Information. The
            Portfolios typically use derivatives as a substitute for taking a
            position in the underlying asset and/or part of a strategy
            designed to reduce exposure to other risks, such as interest rate
            or currency risk. The Portfolios may also use derivatives for
            leverage, in which case their use would involve leveraging risk. A
            Portfolio's use of derivative instruments involves risks different
            from, or possibly greater than, the risks associated with
            investing directly in securities and other traditional
            investments. Derivatives are subject to a number of risks
            described elsewhere in this section, such as liquidity risk,
            interest rate risk, market risk, credit risk and management risk.
            They also involve the risk of mispricing or improper valuation and
            the risk that changes in the value of the derivative may not
            correlate perfectly with the underlying asset, rate or index. A
            Portfolio investing in a derivative instrument could lose more
            than the principal amount invested. Also, suitable derivative
            transactions may not be available in all circumstances and there
            can be no assurance that a Portfolio will engage in these
            transactions to reduce exposure to other risks when that would be
            beneficial.

Mortgage    A Portfolio that purchases mortgage-related securities is subject
Risk        to certain additional risks. Rising interest rates tend to extend
            the duration of mortgage-related securities, making them more
            sensitive to changes in interest rates. As a result, in a period
            of rising interest rates, a Portfolio that holds mortgage-related
            securities may exhibit additional volatility. This is known as
            extension risk. In addition, mortgage-related securities are
            subject to prepayment risk. When interest rates decline, borrowers
            may pay off their mortgages sooner than expected. This can reduce
            the returns of a Portfolio because the Portfolio will have to
            reinvest that money at the lower prevailing interest rates.

Foreign     A Portfolio that invests in foreign securities may experience more
(Non-       rapid and extreme changes in value than a Portfolio that invests
U.S.)       exclusively in securities of U.S. companies. The securities
Investment  markets of many foreign countries are relatively small, with a
Risk        limited number of companies representing a small number of
            industries. Additionally, issuers of foreign securities are
            usually not subject to the same degree of regulation as U.S.
            issuers. Reporting, accounting and auditing standards of foreign
            countries differ, in some cases significantly, from U.S.
            standards. Also, nationalization, expropriation or confiscatory
            taxation, currency blockage, political changes or diplomatic
            developments could adversely affect a Portfolio's investments in a
            foreign country. In the event of nationalization, expropriation or
            other confiscation, a Portfolio could lose its entire investment
            in foreign securities. Adverse conditions in a certain region can
            adversely affect securities of other countries whose economies
            appear to be unrelated. To the extent that a Portfolio invests a
            significant portion of its assets in a concentrated geographic
            area like Eastern Europe or Asia, the Portfolio will generally
            have more exposure to regional economic risks associated with
            foreign investments.

Currency    Portfolios that invest directly in foreign currencies or in
Risk        securities that trade in, and receive revenues in, foreign (non-
            U.S.) currencies are subject to the risk that those currencies
            will decline in value relative to the U.S. dollar, or, in the case
            of hedging positions, that the U.S. dollar will decline in value
            relative to the currency being hedged.

             Currency rates in foreign countries may fluctuate significantly
            over short periods of time for a number of reasons, including
            changes in interest rates, intervention (or the failure to
            intervene) by U.S. or foreign governments, central banks or
            supranational entities such as the International Monetary

                                                                  Prospectus
                                                                              12
<PAGE>

            Fund, or by the imposition of currency controls or other political
            developments in the U.S. or abroad. As a result, a Portfolio's
            investments in foreign currency-denominated securities may reduce
            the returns of a Portfolio.

Leveraging  Certain transactions may give rise to a form of leverage. Such
Risk        transactions may include, among others, reverse repurchase
            agreements, loans of portfolios securities, and the use of when-
            issued, delayed delivery or forward commitment transactions. The
            use of derivatives may also create leveraging risk. To mitigate
            leveraging risk, PIMCO will segregate liquid assets or otherwise
            cover the transactions that may give rise to such risk. The use of
            leverage may cause a Portfolio to liquidate portfolio positions
            when it may not be advantageous to do so to satisfy its
            obligations or to meet segregation requirements. Leverage,
            including borrowing, may cause a Portfolio to be more volatile
            than if the Portfolio had not been leveraged. This is because
            leverage tends to exaggerate the effect of any increase or
            decrease in the value of a Portfolio's portfolio securities.

Management  Each Portfolio is subject to management risk because it is an
Risk        actively managed investment portfolio. PIMCO and each individual
            portfolio manager will apply investment techniques and risk
            analyses in making investment decisions for the Portfolio, but
            there can be no guarantee that these will produce the desired
            results.

   PIMCO Variable Insurance Trust
13
<PAGE>

            Management of the Portfolios

Investment  PIMCO serves as investment adviser and the administrator (serving
Adviser     in its capacity as administrator, the "Administrator") for the
and         Portfolios. Subject to the supervision of the Board of Trustees,
Admini-     PIMCO is responsible for managing the investment activities of the
strator     Portfolios and the Portfolios' business affairs and other
            administrative matters.

             PIMCO's address is 840 Newport Center Drive, Suite 300, Newport
            Beach, California 92660. Organized in 1971, PIMCO provides
            investment management and advisory services to private accounts of
            institutional and individual clients and to mutual funds. As of
            December 31, 1999, PIMCO had approximately $186 billion in assets
            under management.

Advisory    Each Portfolio pays PIMCO fees in return for providing investment
Fees        advisory services. For the fiscal year ended December 31, 1999,
            the Portfolios paid monthly advisory fees to PIMCO at the
            following annual rates (stated as a percentage of the average
            daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
            Portfolio                  Advisory Fees
            ----------------------------------------
            <S>                        <C>
            Short-Term Bond Portfolio      0.35%
            All other Portfolios           0.40%
</TABLE>

             Effective April 1, 2000, the Portfolios pay monthly advisory fees
            to PIMCO at the following annual rates (stated as a percentage of
            the average daily net assets of each Portfolio taken separately):

<TABLE>
<CAPTION>
            Portfolio
                                                 Advisory Fees
            --------------------------------------------------
            <S>                                     <C>
            StocksPLUS Growth and Income Portfolio      0.40%
            All other Portfolios                        0.25%
</TABLE>

Admini-     Each Portfolio pays for the administrative services it requires
strative    under a fee structure which is essentially fixed. Shareholders of
Fees        each Portfolio pay an administrative fee to PIMCO, computed as a
            percentage of the Portfolio's assets attributable in the aggregate
            to that class of shares. PIMCO, in turn, provides or procures
            administrative services for shareholders and also bears the costs
            of various third-party services required by the Portfolios,
            including audit, custodial, portfolio accounting, legal, transfer
            agency and printing costs. The result of this fee structure is an
            expense level for shareholders of each Portfolio that, with
            limited exceptions, is precise and predictable under ordinary
            circumstances.

             For the fiscal year ended December 31, 1999, the Portfolios paid
            PIMCO monthly administrative fees at the following annual rates:

<TABLE>
<CAPTION>
            Portfolio       Administrative Fees
            -----------------------------------
            <S>             <C>
            All Portfolios         0.25%
</TABLE>

             Effective April 1, 2000, the Portfolios pay PIMCO monthly
            administrative fees at the following annual rates:

<TABLE>
<CAPTION>
            Portfolio                             Administrative Fees
            ------------------------------------------------------
            <S>                                   <C>
            StocksPLUS Growth & Income Portfolio         0.10%
            Short-Term Bond Portfolio                    0.20%
            Total Return Bond Portfolio                  0.25%
</TABLE>

                                                                  Prospectus
                                                                              14
<PAGE>

             PIMCO may use its assets and resources, including its profits
            from advisory or administrative fees paid by a Portfolio, to pay
            insurance companies for services rendered to current and
            prospective owners of Variable Contracts, including the provision
            of support services such as providing information about the Trust
            and the Portfolios, the delivery of Trust documents, and other
            services. Any such payments are made by PIMCO and not by the Trust
            and PIMCO does not receive any separate fees for such expenses.

Individual  The table below provides information about the individual
Portfolio   portfolio managers responsible for management of the Trust's
Managers    Portfolios, including their occupations for the past five years.

<TABLE>
<CAPTION>
                            Portfolio
         Portfolio          Manager          Since    Recent Professional Experience
            --------------------------------------------------------------------------------------
         <C>                <C>              <C>      <S>
         Short-Term Bond    Paul A. McCulley    9/99* Executive Vice President, PIMCO. He has
                                                      managed fixed income assets since joining
                                                      PIMCO in 1999. Prior to joining PIMCO, Mr.
                                                      McCulley was associated with Warburg Dillon
                                                      Read as a Managing Director from 1992-1999
                                                      and Head of Economic and Strategy Research
                                                      for the Americas from 1995-1999, where he
                                                      managed macro research world-wide.

         Total Return Bond  William H. Gross   12/97* Managing Director, Chief Investment Officer
         StocksPLUS                                   and a founding partner of PIMCO. He leads a
          Growth and Income                    12/97* team which manages the StocksPLUS Portfolio.
</TABLE>
            -------
            *  Since inception of the Portfolio.

Distributor The Trust's Distributor is PIMCO Funds Distributors LLC, a wholly
            owned subsidiary of PIMCO Advisors L.P. The Distributor, located
            at 2187 Atlantic Street, Stamford CT 06902, is a broker-dealer
            registered with the Securities and Exchange Commission.

            Investment Options--
            Institutional Class Shares

            Effective April 1, 2000, the Trust offers investors Institutional
            Class and Administrative Class shares of the Portfolios in this
            Prospectus. On that date, outstanding shares of the Trust were
            designated Administrative Class Shares. The Trust does not charge
            any sales charges (loads) or other fees in connection with
            purchases, sales (redemptions) or exchanges of Institutional Class
            shares. Administrative Class shares are subject to a higher level
            of operating expenses than Institutional Class shares due to an
            additional service fee paid by Administrative Class shares.
            Therefore, Institutional Class shares will generally pay higher
            dividends and have a more favorable investment return than
            Administrative Class shares.

   PIMCO Variable Insurance Trust
15
<PAGE>

              . Arrangements with Service Agents. Institutional Class shares
            of the Portfolios may be offered through certain brokers and
            financial intermediaries ("service agents") that have established
            a shareholder servicing relationship with the Trust on behalf of
            their customers. The Trust pays no compensation to such entities
            other than service and/or distribution fees paid with respect to
            Administrative Class shares. Service agents may impose additional
            or different conditions than the Trust on purchases, redemptions
            or exchanges of Portfolio shares by their customers. Service
            agents may also independently establish and charge their customers
            transaction fees, account fees and other amounts in connection
            with purchases, sales and redemptions of Portfolio shares in
            addition to any fees charged by the Trust. These additional fees
            may vary over time and would increase the cost of the customer's
            investment and lower investment returns. Each service agent is
            responsible for transmitting to its customers a schedule of any
            such fees and information regarding any additional or different
            conditions regarding purchases, redemptions and exchanges.
            Shareholders who are customers of service agents should consult
            their service agents for information regarding these fees and
            conditions.

            Purchases and Redemptions

Purchasing  Investors do not deal directly with the Portfolios to purchase and
Shares      redeem shares. Please refer to the prospectus for the Separate
            Account for information on the allocation of premiums and on
            transfers of accumulated value among sub-accounts of the Separate
            Account that invest in the Portfolios.

             As of the date of this Prospectus, shares of the Portfolios are
            offered for purchase by Separate Accounts to serve as an
            investment medium for Variable Contracts issued by life insurance
            companies, and to qualified pension and retirement plans outside
            of the separate account context.

             While the Portfolios currently do not foresee any disadvantages
            to Variable Contract Owners if the Portfolios serve as an
            investment medium for both variable annuity contracts and variable
            life insurance policies, due to differences in tax treatment or
            other considerations, it is theoretically possible that the
            interest of owners of annuity contracts and insurance policies for
            which the Portfolios served as an investment medium might at some
            time be in conflict. However, the Trust's Board of Trustees and
            each insurance company with a separate account

                                                                  Prospectus
                                                                              16
<PAGE>

            allocating assets to the Portfolios are required to monitor events
            to identify any material conflicts between variable annuity
            contract owners and variable life insurance policy owners, and
            would have to determine what action, if any, should be taken in
            the event of such a conflict. If such a conflict occurred, an
            insurance company participating in the Portfolios might be
            required to redeem the investment of one or more of its separate
            accounts from the Portfolios, which might force the Portfolios to
            sell securities at disadvantageous prices.

             The Trust and its distributor each reserves the right, in its
            sole discretion, to suspend the offering of shares of the
            Portfolios or to reject any purchase order, in whole or in part,
            or to redeem shares, in whole or in part, when, in the judgment of
            management, such suspension or rejection is in the best interests
            of the Trust. The sale of shares will be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impracticable for the Portfolios to dispose of
            their securities or to determine fairly the value of their net
            assets, or during any other period as permitted by the SEC for the
            protection of investors. In the event that a Portfolio ceases
            offering its shares, any investments allocated to the Portfolio
            will, subject to any necessary regulatory approvals, be invested
            in another Portfolio.

Redeeming   Shares may be redeemed without charge on any day that the net
Shares      asset value is calculated. All redemption orders are effected at
            the net asset value per share next determined after a redemption
            request is received. Payment for shares redeemed normally will be
            made within seven days.

             Redemption's of Portfolio shares may be suspended when trading on
            the New York Stock Exchange is restricted or during an emergency
            which makes it impractical for the Portfolios to dispose of their
            securities or to determine fairly the value of their net assets,
            or during any other period as permitted by the Securities and
            Exchange Commission for the protection of investors. Under these
            and other unusual circumstances, the Trust may suspend redemption
            or postpone payment for more than seven days, as permitted by law.
            In consideration of the best interests of the remaining
            shareholders, the Trust reserves the right to pay redemption
            proceeds in whole or in part by a distribution in kind of
            securities held by a Portfolio in lieu of cash. It is highly
            unlikely that shares would ever be redeemed in kind. If shares are
            redeemed in kind, however, the redeeming shareholder should expect
            to incur transaction costs upon the disposition of the securities
            received in the distribution.

            How Portfolio Shares Are Priced

            The net asset value ("NAV") of a Portfolio's Institutional Class
            shares is determined by dividing the total value of a Portfolio's
            investments and other assets attributable to that class, less any
            liabilities, by the total number of shares outstanding of that
            class.

             For purposes of calculating NAV, portfolio securities and other
            assets for which market quotes are available are stated at market
            value. Market value is generally determined on the basis of last
            reported sales prices, or if no sales are reported, based on
            quotes obtained from a quotation reporting system, established
            market makers, or pricing services. Certain securities or
            investments for which daily market quotations are not readily
            available may be valued, pursuant to guidelines established by the
            Board of Trustees, with reference to other securities or indices.
            Short-term investments having a maturity of 60 days or less are
            generally valued at amortized cost. Exchange traded options,
            futures and options on futures are valued at the settlement price
            determined by the exchange. Other securities for which market
            quotes are not readily available are valued at fair value as
            determined in good faith by the Board of Trustees or persons
            acting at their direction.

17
   PIMCO Variable Insurance Trust
<PAGE>

             Investments initially valued in currencies other than the U.S.
            dollar are converted to U.S. dollars using exchange rates obtained
            from pricing services. As a result, the NAV of a Portfolio's
            shares may be affected by changes in the value of currencies in
            relation to the U.S. dollar. The value of securities traded in
            markets outside the United States or denominated in currencies
            other than the U.S. dollar may be affected significantly on a day
            that the New York Stock Exchange is closed and an investor is not
            able to purchase, redeem or exchange shares.

             Portfolio shares are valued at the close of regular trading
            (normally 4:00 p.m., Eastern time) (the "NYSE Close") on each day
            that the New York Stock Exchange is open. For purposes of
            calculating the NAV, the Portfolios normally use pricing data for
            domestic equity securities received shortly after the NYSE Close
            and do not normally take into account trading, clearances or
            settlements that take place after the NYSE Close. Domestic fixed
            income and foreign securities are normally priced using data
            reflecting the earlier closing of the principal markets for those
            securities. Information that becomes known to the Portfolios or
            its agents after the NAV has been calculated on a particular day
            will not generally be used to retroactively adjust the price of a
            security or the NAV determined earlier that day.

             In unusual circumstances, instead of valuing securities in the
            usual manner, the Portfolios may value securities at fair value or
            estimate their value as determined in good faith by the Board of
            Trustees, generally based upon recommendations provided by PIMCO.
            Fair valuation may also be used if extraordinary events occur
            after the close of the relevant market but prior to the NYSE
            Close.

             Under certain circumstances, the per share NAV of the
            Administrative Class shares of the Portfolios may be lower than
            the per share NAV of the Institutional Class shares as a result of
            the daily expense accruals of the service fees paid by
            Administrative Class shares. Generally, for Portfolio that pay
            income dividends, those dividends are expected to differ over time
            by approximately the amount of the expense accrual differential
            between the two classes.
            Tax Consequences

            Each Portfolio intends to qualify as a regulated investment
            company annually and to elect to be treated as a regulated
            investment company for federal income tax purposes. As such, a
            Portfolio generally will not pay federal income tax on the income
            and gains it pays as dividends to its shareholders. In order to
            avoid a 4% federal excise tax, each Portfolio intends to
            distribute each year substantially all of its net income and
            gains.

             The Portfolios also intend to comply with diversification
            requirements imposed by regulations under Section 817(h) of the
            Internal Revenue Code, as amended. Compliance with these
            diversification rules generally will limit the ability of a
            Portfolio to invest greater than 55% of its total assets in direct
            obligations of the U.S. Treasury (or any other issuer), or to
            invest primarily in securities issued by a single agency or
            instrumentality of the U.S. Government.

             If a Portfolio fails to meet the diversification requirement
            under Section 817(h), income with respect to Variable Contracts
            invested in the Portfolio at any time during the calendar quarter
            in which the failure occurred could become currently taxable to
            the owners of the Variable Contracts and income for prior periods
            with respect to such contracts also could be taxable, most likely
            in the year of the failure to achieve the required
            diversification. Other adverse tax consequences could also ensue.

             Please refer to the prospectus for the Separate Account and
            Variable Contract for information regarding the federal income tax
            treatment of distributions to the Separate Account. See
            "Additional Information--Additional Tax Information" in the
            Portfolios' Statement of Additional Information for more
            information on taxes.

                                                                  Prospectus
                                                                              18
<PAGE>

            Characteristics and Risks of
            Securities and Investment Techniques

            This section provides additional information about some of the
            principal investments and related risks of the Portfolios
            described under the "Portfolio Summaries" above. It also describes
            characteristics and risks of additional securities and investment
            techniques that may be used by the Portfolios from time to time.
            Most of these securities and investment techniques are
            discretionary, which means that PIMCO can decide whether to use
            them or not. This Prospectus does not attempt to disclose all of
            the various types of securities and investment techniques that may
            be used by the Portfolios. As with any mutual fund, investors in
            the Portfolios rely on the professional investment judgment and
            skill of PIMCO and the individual portfolio managers. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for more detailed information about the
            securities and investment techniques described in this section and
            about other strategies and techniques that may be used by the
            Portfolios.

Securities  Most of the Portfolios in this prospectus seek maximum total
Selection   return. The total return sought by a Portfolio consists of both
            income earned on a Portfolio's investments and capital
            appreciation, if any, arising from increases in the market value
            of a Portfolio's holdings. Capital appreciation of fixed income
            securities generally results from decreases in market interest
            rates or improving credit fundamentals for a particular market
            sector or security.

             In selecting securities for a Portfolio, PIMCO develops an
            outlook for interest rates, foreign currency exchange rates and
            the economy; analyzes credit and call risks, and uses other
            security selection techniques. The proportion of a Portfolio's
            assets committed to investment in securities with particular
            characteristics (such as quality, sector, interest rate or
            maturity) varies based on PIMCO's outlook for the U.S. and foreign
            economies, the financial markets and other factors.

             PIMCO attempts to identify areas of the bond market that are
            undervalued relative to the rest of the market. PIMCO identifies
            these areas by grouping bonds into the following sectors: money
            markets, governments, corporates, mortgages, asset-backed and
            international. Sophisticated proprietary software then assists in
            evaluating sectors and pricing specific securities. Once
            investment opportunities are identified, PIMCO will shift assets
            among sectors depending upon changes in relative valuations and
            credit spreads. There is no guarantee that PIMCO's security
            selection techniques will produce the desired results.

U.S.        U.S. Government securities are obligations of and, in certain
Government  cases, guaranteed by, the U.S. Government, its agencies or
Securities  government-sponsored enterprises. U.S. Government Securities are
            subject to market and interest rate risk, and may be subject to
            varying degrees of credit risk. U.S. Government securities may
            include zero coupon securities, which do not distribute interest
            on a current basis and tend to be subject to greater market risk
            than interest-paying securities of similar maturities.

Muncipal    Municipal bonds are generally issued by states and local
Bonds       governments and their agencies, authorities and other
            instumentalities. Municipal bonds are subject to interest rate,
            credit and market risk. The ability of an issuer to make payments
            could be affected by litigation, legislation or other political
            events or the bankruptcy of the issuer. Lower rated municipal
            bonds are subject to greater credit and market risk than higher
            quality municipal bonds. The types of municipal bonds in which the
            Portfolios may invest include municipal lease obligations. The
            Portfolios may also invest in securities issued by entities whose
            underlying assets are municipal bonds.

Mortgage-   Each Portfolio may invest all of its assets in mortgage- and
Related     asset-backed securities. Mortgage-related securities include
and Other   mortgage pass-through securities, collateralized mortgage
Asset-      obligations ("CMOs"), commercial mortgage-backed securities,
Backed      mortgage dollar rolls, CMO residuals, stripped mortgage-backed
Securities  securities ("SMBSs") and other securities that directly or
            indirectly represent a participation in, or are secured by and
            payable from, mortgage loans on real property.

   PIMCO Variable Insurance Trust
19
<PAGE>

             The value of some mortgage- or asset-backed securities may be
            particularly sensitive to changes in prevailing interest rates.
            Early repayment of principal on some mortgage-related securities
            may expose a Portfolio to a lower rate of return upon reinvestment
            of principal. When interest rates rise, the value of a mortgage-
            related security generally will decline; however, when interest
            rates are declining, the value of mortgage-related securities with
            prepayment features may not increase as much as other fixed income
            securities. The rate of prepayments on underlying mortgages will
            affect the price and volatility of a mortgage-related security,
            and may shorten or extend the effective maturity of the security
            beyond what was anticipated at the time of purchase. If
            unanticipated rates of prepayment on underlying mortgages increase
            the effective maturity of a mortgage-related security, the
            volatility of the security can be expected to increase. The value
            of these securities may fluctuate in response to the market's
            perception of the creditworthiness of the issuers. Additionally,
            although mortgages and mortgage-related securities are generally
            supported by some form of government or private guarantee and/or
            insurance, there is no assurance that private guarantors or
            insurers will meet their obligations.

             One type of SMBS has one class receiving all of the interest from
            the mortgage assets (the interest-only, or "IO" class), while the
            other class will receive all of the principal (the principal-only,
            or "PO" class). The yield to maturity on an IO class is extremely
            sensitive to the rate of principal payments (including
            prepayments) on the underlying mortgage assets, and a rapid rate
            of principal payments may have a material adverse effect on a
            Portfolio's yield to maturity from these securities. A Portfolio
            may not invest more than 5% of its net assets in any combination
            of IO, PO, or inverse floater securities. The Portfolios may
            invest in other asset-backed securities that have been offered to
            investors.

Loan        Certain Portfolios may invest in fixed- and floating-rate loans,
Partici-    which investments generally will be in the form of loan
pations     participations and assignments of portions of such loans.
and         Participations and assignments involve special types of risk,
Assign-     including credit risk, interest rate risk, liquidity risk, and the
ments       risks of being a lender. If a Portfolio purchases a participation,
            it may only be able to enforce its rights through the lender, and
            may assume the credit risk of the lender in addition to the
            borrower.

Corporate   Corporate debt securities are subject to the risk of the issuer's
Debt        inability to meet principal and interest payments on the
Securities  obligation and may also be subject to price volatility due to such
            factors as interest rate sensitivity, market perception of the
            credit-worthiness of the issuer and general market liquidity. When
            interest rates rise, the value of corporate debt securities can be
            expected to decline. Debt securities with longer maturities tend
            to be more sensitive to interest rate movements than those with
            shorter maturities.

High        Securities rated lower than Baa by Moody's Investors Service, Inc.
Yield       ("Moody's") or lower than BBB by Standard & Poor's Ratings
Securities  Services ("S&P") are sometimes referred to as "high yield" or
            "junk" bonds. Investing in high yield securities involves special
            risks in addition to the risks associated with investments in
            higher-rated fixed income securities. While offering a greater
            potential opportunity for capital appreciation and higher yields,
            high yield securities typically entail greater potential price
            volatility and may be less liquid than higher-rated securities.
            High yield securities may be regarded as predominately speculative
            with respect to the issuer's continuing ability to meet principal
            and interest payments. They may also be more susceptible to real
            or perceived adverse economic and competitive industry conditions
            than higher-rated securities.

              . Credit Ratings and Unrated Securities. Rating agencies are
            private services that provide ratings of the credit quality of
            fixed income securities, including convertible securities.
            Appendix A to this Offering Memorandum describes the various
            ratings assigned to fixed income securities by Moody's and S&P.
            Ratings assigned by a rating agency are not absolute standards of
            credit quality and do not evaluate market risks. Rating agencies
            may fail to make timely changes in credit ratings and an issuer's
            current financial condition may be better or worse than a rating
            indicates. A Portfolio will not necessarily sell a security when
            its rating is reduced below its rating at the time of purchase.
            PIMCO does not rely solely on credit ratings, and develops its own
            analysis of issuer credit quality.

                                                                  Prospectus
                                                                              20
<PAGE>

             A Portfolio may purchase unrated securities (which are not rated
            by a rating agency) if its portfolio manager determines that the
            security is of comparable quality to a rated security that the
            Portfolio may purchase. Unrated securities may be less liquid than
            comparable rated securities and involve the risk that the
            portfolio manager may not accurately evaluate the security's
            comparative credit rating. Analysis of the creditworthiness of
            issuers of high yield securities may be more complex than for
            issuers of higher-quality fixed income securities. To the extent
            that a Portfolio invests in high yield and/or unrated securities,
            the Portfolio's success in achieving its investment objective may
            depend more heavily on the portfolio manager's creditworthiness
            analysis than if the Portfolio invested exclusively in higher-
            quality and rated securities.

Variable    Variable and floating rate securities provide for a periodic
and         adjustment in the interest rate paid on the obligations. Each
Floating    Portfolio may invest in floating rate debt instruments
Rate        ("floaters") and engage in credit spread trades. While floaters
Securities  provide a certain degree of protection against rises in interest
            rates, a Portfolio will participate in any declines in interest
            rates as well. Each Portfolio may also invest in inverse floating
            rate debt instruments ("inverse floaters"). An inverse floater may
            exhibit greater price volatility than a fixed rate obligation of
            similar credit quality. A Portfolio may not invest more than 5% of
            its assets in any combination of inverse floater, interest only,
            or principal only securities.

Inflation-  Inflation-indexed bonds are fixed income securities whose
Indexed     principal value is periodically adjusted according to the rate of
Bonds       inflation. If the index measuring inflation falls, the principal
            value of inflation-indexed bonds will be adjusted downward, and
            consequently the interest payable on these securities (calculated
            with respect to a smaller principal amount) will be reduced.
            Repayment of the original bond principal upon maturity (as
            adjusted for inflation) is guaranteed in the case of U.S. Treasury
            inflation-indexed bonds. For bonds that do not provide a similar
            guarantee, the adjusted principal value of the bond repaid at
            maturity may be less than the original principal.

             The value of inflation-indexed bonds is expected to change in
            response to changes in real interest rates. Real interest rates
            are tied to the relationship between nominal interest rates and
            the rate of inflation. If nominal interest rates increase at a
            faster rate than inflation, real interest rates may rise, leading
            to a decrease in value of inflation-indexed bonds. Short-term
            increases in inflation may lead to a decline in value. Any
            increase in the principal amount of an inflation-indexed bond will
            be considered taxable ordinary income, even though investors do
            not receive their principal until maturity.

Event-      Each Portfolio may invest in "event-linked bonds," which are fixed
Linked      income securities for which the return of principal and payment of
Bonds       interest is contingent on the non-occurrence of a specific
            "trigger" event, such as a hurricane, earthquake or other physical
            or weather-related phenomenon. Some event-linked bonds are
            commonly referred to as "catastrophe bonds." If a trigger event
            occurs, a Portfolio may lose a portion or all of its principal
            invested in the bond. Event-linked bonds often provide for an
            extension of maturity to process and audit loss claims where a
            trigger event has, or possibly has, occurred. Event-linked bonds
            may also expose the Portfolio to certain unanticipated risks
            including but not limited to issuer (credit) default, adverse
            regulatory or jurisdictional interpretation, and adverse tax
            consequences. Event-linked bonds may also be subject to liquidity
            risk.

Convertible Each Portfolio may invest in convertible securities. Convertible
and         securities are generally preferred stocks and other securities,
Equity      including fixed income securities and warrants, that are
Securities  convertible into or exercisable for common stock at a stated price
            or rate. The price of a convertible security will normally vary in
            some proportion to changes in the price of the underlying common
            stock because of this conversion or exercise feature. However, the
            value of a convertible security may not increase or decrease as
            rapidly as the underlying common stock. A convertible security
            will normally also provide income and is subject to interest rate
            risk. Convertible securities may be lower-rated securities subject
            to greater levels of credit risk. A Portfolio may be forced to
            convert a security before it would otherwise choose, which may
            have an adverse effect on the Portfolio's ability to achieve its
            investment objective.

   PIMCO Variable Insurance Trust
21
<PAGE>

             While the Fixed Income Portfolios intend to invest primarily in
            fixed income securities, each may invest in convertible securities
            or equity securities. While some countries or companies may be
            regarded as favorable investments, pure fixed income opportunities
            may be unattractive or limited due to insufficient supply, or
            legal or technical restrictions. In such cases, a Portfolio may
            consider convertible securities or equity securities to gain
            exposure to such investments.

             Equity securities generally have greater price volatility than
            fixed income securities. The market price of equity securities
            owned by a Portfolio may go up or down, sometimes rapidly or
            unpredictably. Equity securities may decline in value due to
            factors affecting equity securities markets generally or
            particular industries represented in those markets. The value of
            an equity security may also decline for a number of reasons which
            directly relate to the issuer, such as management performance,
            financial leverage and reduced demand for the issuer's goods or
            services.

            Investing in the securities of issuers in any foreign country
Foreign     involves special risks and considerations not typically associated
(Non-       with investing in U.S. companies. Shareholders should consider
U.S.)       carefully the substantial risks involved for Portfolios that
Securities  invest in securities issued by foreign companies and governments
            of foreign countries. These risks include: differences in
            accounting, auditing and financial reporting standards; generally
            higher commission rates on foreign portfolio transactions; the
            possibility of nationalization, expropriation or confiscatory
            taxation; adverse changes in investment or exchange control
            regulations; and political instability. Individual foreign
            economies may differ favorably or unfavorably from the U.S.
            economy in such respects as growth of gross domestic product,
            rates of inflation, capital reinvestment, resources, self-
            sufficiency and balance of payments position. The securities
            markets, values of securities, yields and risks associated with
            foreign securities markets may change independently of each other.
            Also, foreign securities and dividends and interest payable on
            those securities may be subject to foreign taxes, including taxes
            withheld from payments on those securities. Foreign securities
            often trade with less frequency and volume than domestic
            securities and therefore may exhibit greater price volatility.
            Investments in foreign securities may also involve higher
            custodial costs than domestic investments and additional
            transaction costs with respect to foreign currency conversions.
            Changes in foreign exchange rates also will affect the value of
            securities denominated or quoted in foreign currencies.

             Certain Portfolios also may invest in sovereign debt issued by
            governments, their agencies or instrumentalities, or other
            government-related entities. Holders of sovereign debt may be
            requested to participate in the rescheduling of such debt and to
            extend further loans to governmental entities. In addition, there
            is no bankruptcy proceeding by which defaulted sovereign debt may
            be collected.

              . Emerging Market Securities. The Short-Term Bond Portfolio may
            invest up to 5% of its assets in securities of issuers based in
            countries with developing (or "emerging market") economies and
            each remaining Portfolio that may invest in foreign securities may
            invest up to 10% of its assets in such securities. Investing in
            emerging market securities imposes risks different from, or
            greater than, risks of investing in domestic securities or in
            foreign, developed countries. These risks include: smaller market
            capitalization of securities markets, which may suffer periods of
            relative illiquidity; significant price volatility; restrictions
            on foreign investment; possible repatriation of investment income
            and capital. In addition, foreign investors may be required to
            register the proceeds of sales; future economic or political
            crises could lead to price controls, forced mergers, expropriation
            or confiscatory taxation, seizure, nationalization, or creation of
            government monopolies. The currencies of emerging market countries
            may experience significant declines against the U.S. dollar, and
            devaluation may occur subsequent to investments in these
            currencies by a Portfolio. Inflation and rapid fluctuations in
            inflation rates have had, and may continue to have, negative
            effects on the economies and securities markets of certain
            emerging market countries.

             Additional risks of emerging markets securities may include:
            greater social, economic and political uncertainty and
            instability; more substantial governmental involvement in the
            economy; less governmental supervision and regulation;
            unavailability of currency hedging techniques; companies that are
            newly organized and small; differences in auditing and financial
            reporting standards, which may result in unavailability of
            material information about issuers; and less developed legal
            systems. In addition, emerging securities markets may have
            different

                                                                Prospectus
                                                                              22
<PAGE>

            clearance and settlement procedures, which may be unable to keep
            pace with the volume of securities transactions or otherwise make
            it difficult to engage in such transactions. Settlement problems
            may cause a Portfolio to miss attractive investment opportunities,
            hold a portion of its assets in cash pending investment, or be
            delayed in disposing of a portfolio security. Such a delay could
            result in possible liability to a purchaser of the security.

             Each Portfolio may invest in Brady Bonds, which are securities
            created through the exchange of existing commercial bank loans to
            sovereign entities for new obligations in connection with a debt
            restructuring. Investments in Brady Bonds may be viewed as
            speculative. Brady Bonds acquired by a Portfolio may be subject to
            restructuring arrangements or to requests for new credit, which
            may cause the Portfolio to suffer a loss of interest or principal
            on any of its holdings.

Foreign     A Portfolio that invests directly in foreign currencies or in
(Non-       securities that trade in, or receive revenues in, foreign
U.S.)       currencies will be subject to currency risk. Foreign currency
Currencies  exchange rates may fluctuate significantly over short periods of
            time. They generally are determined by supply and demand in the
            foreign exchange markets and the relative merits of investments in
            different countries, actual or perceived changes in interest rates
            and other complex factors. Currency exchange rates also can be
            affected unpredictably by intervention (or the failure to
            intervene) by U.S. or foreign governments or central banks, or by
            currency controls or political developments. For example,
            uncertainty surrounds the introduction of the euro (a common
            currency unit for the European Union) and the effect it may have
            on the value of European currencies as well as securities
            denominated in local European currencies. These and other
            currencies in which the Portfolios' assets are denominated may be
            devalued against the U.S. dollar, resulting in a loss to the
            Portfolios.

              . Foreign Currency Transactions. Portfolios that invest in
            securities denominated in foreign currencies may enter into
            forward foreign currency exchange contracts and invest in foreign
            currency futures contracts and options on foreign currencies and
            futures. A forward foreign currency exchange contract, which
            involves an obligation to purchase or sell a specific currency at
            a future date at a price set at the time of the contract, reduces
            a Portfolio's exposure to changes in the value of the currency it
            will deliver and increases its exposure
            to changes in the value of the currency it will receive for the
            duration of the contract. The effect on the value of a Portfolio
            is similar to selling securities denominated in one currency and
            purchasing securities denominated in another currency. A contract
            to sell foreign currency would limit any potential gain which
            might be realized if the value of the hedged currency increases. A
            Portfolio may enter into these contracts to hedge against foreign
            exchange risk, to increase exposure to a foreign currency or to
            shift exposure to foreign currency fluctuations from one currency
            to another. Suitable hedging transactions may not be available in
            all circumstances and there can be no assurance that a Portfolio
            will engage in such transactions at any given time or from time to
            time. Also, such transactions may not be successful and may
            eliminate any chance for a Portfolio to benefit from favorable
            fluctuations in relevant foreign currencies. A Portfolio may use
            one currency (or a basket of currencies) to hedge against adverse
            changes in the value of another currency (or a basket of
            currencies) when exchange rates between the two currencies are
            positively correlated. The Portfolio will segregate assets
            determined to be liquid by PIMCO in accordance with procedures
            established by the Board of Trustees to cover its obligations
            under forward foreign currency exchange contracts entered into for
            non-hedging purposes.

Repurchase  Each Portfolio may enter into repurchase agreements, in which the
Agreements  Portfolio purchases a security from a bank or broker-dealer and
            agrees to repurchase the security at the Portfolio's cost plus
            interest within a specified time. If the party agreeing to
            repurchase should default, the Portfolio will seek to sell the
            securities which it holds. This could involve procedural costs or
            delays in addition to a loss on the securities if their value
            should fall below their repurchase price. Repurchase agreements
            maturing in more than seven days are considered illiquid
            securities.


   PIMCO Variable Insurance Trust
23
<PAGE>

Reverse     Each Portfolio may enter into reverse repurchase agreements and
Repurchase  dollar rolls, subject to the Portfolio's limitations on
Agreements, borrowings. A reverse repurchase agreement or dollar roll involves
Dollar      the sale of a security by a Portfolio and its agreement to
Rolls and   repurchase the instrument at a specified time and price, and may
Other       be considered a form of borrowing for some purposes. A Portfolio
Borrowings  will segregate assets determined to be liquid by PIMCO in
            accordance with procedures established by the Board of Trustees to
            cover its obligations under reverse repurchase agreements, dollar
            rolls, and other borrowings. Reverse repurchase agreements, dollar
            rolls and other forms of borrowings may create leveraging risk for
            a Portfolio.

             Each Portfolio may borrow money to the extent permitted under the
            Investment Company Act of 1940 ("1940 Act"), as amended. This
            means that, in general, a Portfolio may borrow money from banks
            for any purpose on a secured basis in an amount up to 1/3 of the
            Portfolio's total assets. A Portfolio may also borrow money for
            temporary administrative purposes on an unsecured basis in an
            amount not to exceed 5% of the Portfolio's total assets.

Derivatives Each Portfolio may, but is not required to, use derivative
            instruments for risk management purposes or as part of its
            investment strategies. Generally, derivatives are financial
            contracts whose value depends upon, or is derived from, the value
            of an underlying asset, reference rate or index, and may relate to
            stocks, bonds, interest rates, currencies or currency exchange
            rates, commodities, and related indexes. Examples of derivative
            instruments include options contracts, futures contracts, options
            on futures contracts and swap agreements. Each Portfolio may
            invest all of its assets in derivative instruments, subject to the
            Portfolio's objective and policies. A portfolio manager may decide
            not to employ any of these strategies and there is no assurance
            that any derivatives strategy used by a Portfolio will succeed. A
            description of these and other derivative instruments that the
            Portfolios may use are described under "Investment Objectives and
            Policies" in the Statement of Additional Information.

             A Portfolio's use of derivative instruments involves risks
            different from, or greater than, the risks associated with
            investing directly in securities and other more traditional
            investments. A description of various risks associated with
            particular derivative instruments is included in "Investment
            Objectives and Policies" in the Statement of Additional
            Information. The following provides a more general discussion of
            important risk factors relating to all derivative instruments that
            may be used by the Portfolios.

             Management Risk. Derivative products are highly specialized
            instruments that require investment techniques and risk analyses
            different from those associated with stocks and bonds. The use of
            a derivative requires an understanding not only of the underlying
            instrument but also of the derivative itself, without the benefit
            of observing the performance of the derivative under all possible
            market conditions.

             Credit Risk. The use of a derivative instrument involves the risk
            that a loss may be sustained as a result of the failure of another
            party to the contract (usually referred to as a "counterparty") to
            make required payments or otherwise comply with the contract's
            terms.

             Liquidity Risk. Liquidity risk exists when a particular
            derivative instrument is difficult to purchase or sell. If a
            derivative transaction is particularly large or if the relevant
            market is illiquid (as is the case with many privately negotiated
            derivatives), it may not be possible to initiate a transaction or
            liquidate a position at an advantageous time or price.

             Leverage Risk. Because many derivatives have a leverage
            component, adverse changes in the value or level of the underlying
            asset, reference rate or index can result in a loss substantially
            greater than the amount invested in the derivative itself. Certain
            derivatives have the potential for unlimited loss, regardless of
            the size of the initial investment. When a Portfolio uses
            derivatives for leverage, investments in that Portfolio will tend
            to be more volatile, resulting in larger gains or losses in
            response to market changes. To limit leverage risk,

                                                                  Prospectus
                                                                              24
<PAGE>

            each Portfolio will segregate assets determined to be liquid by
            PIMCO in accordance with procedures established by the Board of
            Trustees (or, as permitted by applicable regulation, enter into
            certain offsetting positions) to cover its obligations under
            derivative instruments.

             Lack of Availability. Because the markets for certain derivative
            instruments (including markets located in foreign countries) are
            relatively new and still developing, suitable derivatives
            transactions may not be available in all circumstances for risk
            management or other purposes. There is no assurance that a
            Portfolio will engage in derivatives transactions at any time or
            from time to time. A Portfolio's ability to use derivatives may
            also be limited by certain regulatory and tax considerations.

             Market and Other Risks. Like most other investments, derivative
            instruments are subject to the risk that the market value of the
            instrument will change in a way detrimental to a Portfolio's
            interest. If a portfolio manager incorrectly forecasts the values
            of securities, currencies or interest rates or other economic
            factors in using derivatives for a Portfolio, the Portfolio might
            have been in a better position if it had not entered into the
            transaction at all. While some strategies involving derivative
            instruments can reduce the risk of loss, they can also reduce the
            opportunity for gain or even result in losses by offsetting
            favorable price movements in other Portfolio investments. A
            Portfolio may also have to buy or sell a security at a
            disadvantageous time or price because the Portfolio is legally
            required to maintain offsetting positions or asset coverage in
            connection with certain derivatives transactions.

             Other risks in using derivatives include the risk of mispricing
            or improper valuation of derivatives and the inability of
            derivatives to correlate perfectly with underlying assets, rates
            and indexes. Many derivatives, in particular privately negotiated
            derivatives, are complex and often valued subjectively. Improper
            valuations can result in increased cash payment requirements to
            counterparties or a loss of value to a Portfolio. Also, the value
            of derivatives may not correlate perfectly, or at all, with the
            value of the assets, reference rates or indexes they are designed
            to closely track. In addition, a Portfolio's use of derivatives
            may cause the Portfolio to realize higher amounts of short-term
            capital gains (generally taxed at ordinary income tax rates) than
            if the Portfolio had not used such instruments.

Delayed     The Portfolios may also enter into, or acquire participations in,
Funding     delayed funding loans and revolving credit facilities, in which a
Loans and   lender agrees to make loans up to a maximum amount upon demand by
Revolving   the borrower during a specified term. These commitments may have
Credit      the effect of requiring a Portfolio to increase its investment in
Facilities  a company at a time when it might not otherwise decide to do so
            (including at a time when the company's financial condition makes
            it unlikely that such amounts will be repaid). To the extent that
            a Portfolio is committed to advance additional funds, it will
            segregate assets determined to be liquid by PIMCO in accordance
            with procedures established by the Board of Trustees in an amount
            sufficient to meet such commitments. Delayed funding loans and
            revolving credit facilities are subject to credit, interest rate
            and liquidity risk and the risks of being a lender.

When-       Each Portfolio may purchase securities which it is eligible to
Issued,     purchase on a when-issued basis, may purchase and sell such
Delayed     securities for delayed delivery and may make contracts to purchase
Delivery    such securities for a fixed price at a future date beyond normal
and         settlement time (forward commitments). When-issued transactions,
Forward     delayed delivery purchases and forward commitments involve a risk
Commitment  of loss if the value of the securities declines prior to the
Transactionssettlement date. This risk is in addition to the risk that the
            Portfolio's other assets will decline in the value. Therefore,
            these transactions may result in a form of leverage and increase a
            Portfolio's overall investment exposure. Typically, no income
            accrues on securities a Portfolio has committed to purchase prior
            to the time delivery of the securities is made, although a
            Portfolio may earn income on securities it has segregated to cover
            these positions.


   PIMCO Variable Insurance Trust
25
<PAGE>

Investment  Each Portfolio may invest up to 10% of its assets in securities of
in Other    other investment companies, such as closed-end management
Investment  investment companies, or in pooled accounts or other investment
Companies   vehicles which invest in foreign markets. As a shareholder of any
            investment company, a Portfolio may indirectly bear service and
            other fees which are in addition to the fees the Portfolio pays
            its service providers.

             Subject to the restrictions and limitations of the 1940 Act, each
            Portfolio may, in the future, elect to pursue its investment
            objective by investing in one or more underlying investment
            vehicles or companies that have substantially similar investment
            objectives, policies and limitations as the Portfolio.

Short       Each Portfolio may make short sales as part of its overall
Sales       portfolio management strategies or to offset a potential decline
            in value of a security. A short sale involves the sale of a
            security that is borrowed from a broker or other institution to
            complete the sale. Short sales expose a Portfolio to the risk that
            it will be required to acquire, convert or exchange securities to
            replace the borrowed securities (also known as "covering" the
            short position) at a time when the securities sold short have
            appreciated in value, thus resulting in a loss to the Portfolio. A
            Portfolio making a short sale must segregate assets determined to
            be liquid by PIMCO in accordance with procedures established by
            the Board of Trustees or otherwise cover its position in a
            permissible manner.

Illiquid    Each Portfolio may invest up to 15% of its net assets in illiquid
Securities  securities. Certain illiquid securities may require pricing at
            fair value as determined in good faith under the supervision of
            the Board of Trustees. A portfolio manager may be subject to
            significant delays in disposing of illiquid securities, and
            transactions in illiquid securities may entail registration
            expenses and other transaction costs that are higher than those
            for transactions in liquid securities. The term "illiquid
            securities" for this purpose means securities that cannot be
            disposed of within seven days in the ordinary course of business
            at approximately the amount at which a Portfolio has valued the
            securities. Restricted securities, i.e., securities subject to
            legal or contractual restrictions on resale, may be illiquid.
            However, some restricted securities (such as securities issued
            pursuant to Rule 144A under the Securities Act of 1933 and certain
            commercial paper) may be treated as liquid, although they may be
            less liquid than registered securities traded on established
            secondary markets.

Loans of    For the purpose of achieving income, each Portfolio may lend its
Portfolio   portfolio securities to brokers, dealers, and other financial
Securities  institutions provided a number of conditions are satisfied,
            including that the loan is fully collateralized. Please see
            "Investment Objectives and Policies" in the Statement of
            Additional Information for details. When a Portfolio lends
            portfolio securities, its investment performance will continue to
            reflect changes in the value of the securities loaned, and the
            Portfolio will also receive a fee or interest on the collateral.
            Securities lending involves the risk of loss of rights in the
            collateral or delay in recovery of the collateral if the borrower
            fails to return the security loaned or becomes insolvent. A
            Portfolio may pay lending fees to a party arranging the loan.

Portfolio   The length of time a Portfolio has held a particular security is
Turnover    not generally a consideration in investment decisions. A change in
            the securities held by a Portfolio is known as "portfolio
            turnover." Each Portfolio may engage in frequent and active
            trading of portfolio securities to achieve its investment
            objective, particularly during periods of volatile market
            movements. High portfolio turnover (e.g., over 100%) involves
            correspondingly greater expenses to a Portfolio, including
            brokerage commissions or dealer mark-ups and other transaction
            costs on the sale of securities and reinvestments in other
            securities. Such sales may also result in realization of taxable
            capital gains, including short-term capital gains (which are
            generally taxed at ordinary income tax rates). The trading costs
            and tax effects associated with portfolio turnover may adversely
            effect the Portfolio's performance.


                                                                  Prospectus
                                                                              26
<PAGE>

Temporary   For temporary or defensive purposes, the Portfolios may invest
Defensive   without limit in U.S. debt securities, including taxable
Positions   securities and short-term money market securities, when PIMCO
            deems it appropriate to do so. When a Portfolio engages in such
            strategies, it may not achieve its investment objective.

Changes     The investment objective of each Portfolio is fundamental and may
in          not be changed without shareholder approval. Unless otherwise
Investment  stated, all other investment policies of the Portfolios may be
Objectives  changed by the Board of Trustees without shareholder approval.
and
Policies

Percentage  Unless otherwise stated, all percentage limitations on Portfolio
Investment  investments listed in this Prospectus will apply at the time of
Limitations investment. A Portfolio would not violate these limitations unless
            an excess or deficiency occurs or exists immediately after and as
            a result of an investment.

Other       The Portfolios may invest in other types of securities and use a
Investments variety of investment techniques and strategies which are not
and         described in this Prospectus. These securities and techniques may
Techniques  subject the Portfolios to additional risks. Please see the
            Statement of Additional Information for additional information
            about the securities and investment techniques described in this
            Prospectus and about additional securities and techniques that may
            be used by the Portfolios.

   PIMCO Variable Insurance Trust
27
<PAGE>

                      (THIS PAGE INTENTIONALLY LEFT BLANK)

                                                                  Prospectus
                                                                              28
<PAGE>

            Financial Highlights

            The financial highlights table is intended to help a shareholder
            understand the Portfolio's financial performance for the period of
            operations. Certain information reflects financial results for a
            single Portfolio share. The total returns in the table represent
            the rate that an investor would have earned or lost on an
            investment in a particular class of shares of a Portfolio
            (assuming reinvestment of all dividends and distributions). This
            information has been audited by PricewaterhouseCoopers LLP, the
            Portfolio's independent auditors. Their report, along with full
            financial statements, appears in the Trust's Annual Report, which
            is available upon request.

<TABLE>
<CAPTION>
                      Net Asset             Net Realized  Total Income Dividends  Dividends in  Distributions Distributions
Year or                 Value      Net     and Unrealized (Loss) from   from Net  Excess of Net   from Net    in Excess of
Period                Beginning Investment Gain (Loss) on  Investment  Investment  Investment     Realized    Net Realized
Ended                 of Period Income(b)   Investments    Operations    Income      Income     Capital Gains Capital Gains
- ---------------------------------------------------------------------------------------------------------------------------
<S>                   <C>       <C>        <C>            <C>          <C>        <C>           <C>           <C>
Short-Term
 Administrative Class
 12/31/1999(a)         $10.00     $0.13        $ 0.00 (b)     $0.13      $(0.13)     $ 0.00        $ 0.00         $0.00
Total Return
 Administrative Class
 12/31/1999            $10.09     $0.58        $(0.64)(b)    $(0.06)     $(0.58)     $ 0.00        $ 0.00         $0.00
 12/31/1998(e)          10.00      0.56          0.28 (b)      0.84       (0.56)       0.00         (0.19)         0.00
StocksPLUS Growth and Income
 Administrative Class
 12/31/1999            $12.58     $0.76        $ 1.65 (b)    $ 2.41      $(0.61)     $(0.82)       $ 0.00         $0.00
 12/31/1998(e)          10.00      0.30          2.68 (b)      2.98       (0.29)      (0.11)         0.00          0.00
</TABLE>
- -------
(a) Commenced operations on September 30, 1999.
(b) Per share amounts based on average number of shares outstanding during the
    period.
(e) Commenced operations on December 31, 1997.

   PIMCO Variable Insurance Trust
29
<PAGE>




<TABLE>
<CAPTION>
                                                                     Ratio of Net
Tax Basis                Net Asset          Net Assets  Ratio of      Investment
 Return                    Value               End     Expenses to    Income to   Portfolio
   of          Total        End    Total    of Period    Average       Average    Turnover
 Capital   Distributions of Period Return     (000's)  Net Assets     Net Assets    Rate
- -------------------------------------------------------------------------------------------
<S>        <C>           <C>       <C>      <C>        <C>           <C>          <C>


  $0.00       $(0.13)     $10.00    1.32 %   $  3,040     0.60%*(c)      5.17%*      N/A


  $0.00       $(0.58)     $ 9.45   (0.58)%   $  3,877     0.65% (d)      5.96%       102%
   0.00        (0.75)      10.09    8.61        3,259     0.65           5.55        139


  $0.00       $(1.43)     $13.56   19.85 %   $230,412     0.65%          5.69%        34%
   0.00        (0.40)      12.58   30.11       58,264     0.65           5.30         61
</TABLE>
- -------
*   Annualized.
(c) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 1.42%* for the
    period ended December 31, 1999.
(d) If the investment manager had not reimbursed expenses, the ratio of
    operating expenses to average net assets would have been 0.69% for the
    period ended December 31, 1999.

                                                                  Prospectus
                                                                              30
<PAGE>

            Other Information


Performance The following table provides information concerning the historical
Information total return performance of the Institutional Class shares of one
of          series of PIMCO Funds: Pacific Investment Management Series
Similar     ("PIMS"). The PIMS series has investment objectives, policies and
Funds       strategies substantially similar to those of its respective PIMCO
            Variable Insurance Trust ("PVIT") Portfolio and is currently
            managed by the same portfolio manager. While the investment
            objectives and policies of the PIMS series and its respective PVIT
            Portfolio are similar, they are not identical and the performance
            of the PIMS series and the PVIT Portfolio will vary. The data is
            provided to illustrate the past performance of PIMCO in managing a
            substantially similar investment portfolio and does not represent
            the past performance of the PVIT Portfolio or the future
            performance of the PVIT Portfolio or its portfolio manager.
            Consequently, potential investors should not consider this
            performance data as an indication of the future performance of the
            PVIT Portfolio or of its portfolio manager.

            The performance data shown below reflects the operating expenses
            of the Institutional Class of the PIMS series. The PIMS series,
            unlike the Portfolios, are not sold to Separate Accounts to fund
            Variable Contracts. As a result, the performance results presented
            below do not take into account charges or deductions against a
            Separate Account or Variable Contract for cost of insurance
            charges, premium loads, administrative fees, maintenance fees,
            premium taxes, mortality and expense risk charges, or other
            charges that may be incurred under a Variable Contract for which
            the Portfolio serves as an underlying investment vehicle. By
            contrast, Variable Contract Owners with contract value allocated
            to the Portfolios will be subject to charges and expenses relating
            to the Variable Contracts and Separate Accounts.

            The PIMS series' performance data shown below is calculated in
            accordance with standards prescribed by the SEC for the
            calculation of average annual total return information. The
            investment results of the PIMS series presented below are
            unaudited and are not intended to predict or suggest results that
            might be experienced by the PIMS series or the Portfolio. Share
            prices and investment returns will fluctuate reflecting market
            conditions, as well as changes in company-specific fundamentals of
            portfolio securities. The performance data for the benchmark index
            identified below does not reflect the fees or expenses of the PIMS
            series or the Portfolio.

   Average Annual Total Return for Similar Series of PIMS Institutional Class
         and for Benchmark Indices for Periods Ended December 31, 1999

<TABLE>
<CAPTION>
                                                           Since   Inception
                                  1 Year 3 Years 5 Years Inception   Date
- ----------------------------------------------------------------------------
<S>                               <C>    <C>     <C>     <C>       <C>
PIMCO Short-Term Fund/1/           5.24   5.83    6.73     6.41     10/7/87
 Salomon 3-Month Treasury Bill/2/  4.73   5.01    5.20
</TABLE>
- -------
/1/Prior to January 1998 and August 1999 the Short-Term Fund was managed by
  different portfolio managers.
/2/The Salomon 3-Month Treasury Bill Index is an unmanaged index representing
  monthly return equivalents of yield averages of the last 3 month Treasury
  Bill issues. It is not possible to invest directly in the index.

   PIMCO Variable Insurance Trust
31
<PAGE>


            Appendix A

            Description of Securities Ratings

            A Portfolio's investments may range in quality from securities
            rated in the lowest category in which the Portfolio is permitted
            to invest to securities rated in the highest category (as rated by
            Moody's or S&P or, if unrated, determined by PIMCO to be of
            comparable quality). The percentage of a Portfolio's assets
            invested in securities in a particular rating category will vary.
            Following is a description of Moody's and S&P's ratings applicable
            to fixed income securities.

             High Quality Debt Securities are those rated in one of the two
            highest rating categories (the hightest category for commercial
            pages) or, if unrated, deemed comparable by PIMCO.

             Investment Grade Debt Securities are those rated in one of the
            four highest rating categories, or if unrated deemed comparable by
            PIMCO.

             Below Investment Grade High Yield Securities ("Junk Bonds") are
            those rated lower than Baa by Moody's or BBB by S&P and comparable
            securities. They are deemed predominantly speculative with respect
            to the issuer's ability to repay principal and interest.

             Following is a description of Moody's and S&P's rating categories
            applicable to fixed income securities.

Moody's     Corporate and Municipal Bond Ratings
Investors
Service,     Aaa: Bonds which are rated Aaa are judged to be of the best
Inc.        quality. They carry the smallest degree of investment risk and are
            generally referred to as "gilt edge." Interest payments are
            protected by a large or by an exceptionally stable margin and
            principal is secure. While the various protective elements are
            likely to change, such changes as can be visualized are most
            unlikely to impair the fundamentally strong position of such
            issues.

             Aa: Bonds which are rated Aa are judged to be of high quality by
            all standards. Together with the Aaa group they comprise what are
            generally known as high-grade bonds. They are rated lower than the
            best bonds because margins of protection may not be as large as in
            Aaa securities or fluctuation of protective elements may be of
            greater amplitude or there may be other elements present that make
            the long-term risks appear somewhat larger than with Aaa
            securities.

             A: Bonds which are rated A possess many favorable investment
            attributes and are to be considered as upper-medium-grade
            obligations. Factors giving security to principal and interest are
            considered adequate but elements may be present that suggest a
            susceptibility to impairment sometime in the future.

             Baa: Bonds which are rated Baa are considered as medium-grade
            obligations (i.e., they are neither highly protected nor poorly
            secured). Interest payments and principal security appear adequate
            for the present but certain protective elements may be lacking or
            may be characteristically unreliable over any great length of
            time. Such bonds lack outstanding investment characteristics and
            in fact have speculative characteristics as well.

             Ba: Bonds which are rated Ba are judged to have speculative
            elements; their future cannot be considered as well-assured. Often
            the protection of interest and principal payments may be very
            moderate and thereby not well safeguarded during both good and bad
            times over the future. Uncertainty of position characterizes bonds
            in this class.

             B: Bonds which are rated B generally lack characteristics of a
            desirable investment. Assurance of interest and principal payments
            or of maintenance of other terms of the contract over any long
            period of time may be small.

                                                                  Prospectus
                                                                             A-1
<PAGE>

             Caa: Bonds which are rated Caa are of poor standing. Such issues
            may be in default or there may be present elements of danger with
            respect to principal or interest.

             Ca: Bonds which are rated Ca represent obligations which are
            speculative in a high degree. Such issues are often in default or
            have other marked shortcomings.

             C: Bonds which are rated C are the lowest rated class of bonds
            and issues so rated can be regarded as having extremely poor
            prospects of ever attaining any real investment standing.

             Moody's applies numerical modifiers, 1, 2, and 3 in each generic
            rating classified from Aa through B in its corporate bond rating
            system. The modifier 1 indicates that the security ranks in the
            higher end of its generic rating category; the modifier 2
            indicates a mid-range ranking; and the modifier 3 indicates that
            the issue ranks in the lower end of its generic rating category.

Corporate   Moody's short-term debt ratings are opinions of the ability of
Short-      issuers to repay punctually senior debt obligations which have an
Term Debt   original maturity not exceeding one year. Obligations relying upon
Ratings     support mechanisms such as letters of credit and bonds of
            indemnity are excluded unless explicitly rated.

             Moody's employs the following three designations, all judged to
            be investment grade, to indicate the relative repayment ability of
            rated issuers:

             PRIME-1: Issuers rated Prime-1 (or supporting institutions) have
            a superior ability for repayment of senior short-term debt
            obligations. Prime-1 repayment ability will often be evidenced by
            many of the following characteristics: leading market positions in
            well-established industries; high rates of return on funds
            employed; conservative capitalization structure with moderate
            reliance on debt and ample asset protection; broad margins in
            earnings coverage of fixed financial charges and high internal
            cash generation; and well-established access to a range of
            financial markets and assured sources of alternate liquidity.

             PRIME-2: Issuers rated Prime-2 (or supporting institutions) have
            a strong ability for repayment of senior short-term debt
            obligations. This will normally be evidenced by many of the
            characteristics cited above but to a lesser degree. Earnings
            trends and coverage ratios, while sound, may be more subject to
            variation. Capitalization characteristics, while still
            appropriate, may be more affected by external conditions. Ample
            alternate liquidity is maintained.

             PRIME-3: Issuers rated Prime-3 (or supporting institutions) have
            an acceptable ability for repayment of senior short-term
            obligations. The effect of industry characteristics and market
            compositions may be more pronounced. Variability in earnings and
            profitability may result in changes in the level of debt
            protection measurements and may require relatively high financial
            leverage. Adequate alternate liquidity is maintained.

             NOT PRIME: Issuers rated Not Prime do not fall within any of the
            Prime rating categories.

Standard    Corporate and Municipal Bond Ratings Investment Grade
& Poor's
Ratings      AAA: Debt rated AAA has the highest rating assigned by Standard &
Services    Poor's. Capacity to pay interest and repay principal is extremely
            strong.

             AA: Debt rated AA has a very strong capacity to pay interest and
            repay principal and differs from the highest rated issues only in
            small degree.

             A: Debt rated A has a strong capacity to pay interest and repay
            principal although it is somewhat more susceptible to the adverse
            effects of changes in circumstances and economic conditions than
            debt in higher rated categories.

A-2  PIMCO Variable Insurance Trust
<PAGE>

             BBB: Debt rated BBB is regarded as having an adequate capacity to
            pay interest and repay principal. Whereas it normally exhibits
            adequate protection parameters, adverse economic conditions, or
            changing circumstances are more likely to lead to a weakened
            capacity to pay interest and repay principal for debt in this
            category than in higher-rated categories.

            Speculative Grade

             Debt rated BB, B, CCC, CC, and C is regarded as having
            predominantly speculative characteristics with respect to capacity
            to pay interest and repay principal. BB indicates the least degree
            of speculation and C the highest. While such debt will likely have
            some quality and protective characteristics, these are outweighed
            by large uncertainties or major exposures to adverse conditions.

             BB: Debt rated BB has less near-term vulnerability to default
            than other speculative issues. However, it faces major ongoing
            uncertainties or exposure to adverse business, financial, or
            economic conditions which could lead to inadequate capacity to
            meet timely interest and principal payments. The BB rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied BBB- rating.

             B: Debt rated B has a greater vulnerability to default but
            currently has the capacity to meet interest payments and principal
            repayments. Adverse business, financial, or economic conditions
            will likely impair capacity or willingness to pay interest and
            repay principal. The B rating category also is used for debt
            subordinated to senior debt that is assigned an actual or implied
            BB or BB- rating.

             CCC: Debt rated CCC has a currently identifiable vulnerability to
            default and is dependent upon favorable business, financial, and
            economic conditions to meet timely payment of interest and
            repayment of principal. In the event of adverse business,
            financial or economic conditions, it is not likely to have the
            capacity to pay interest and repay principal. The CCC rating
            category also is used for debt subordinated to senior debt that is
            assigned an actual or implied B or B- rating.

             CC: The rating CC is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC rating.

             C: The rating C is typically applied to debt subordinated to
            senior debt that is assigned an actual or implied CCC-debt rating.
            The C rating may be used to cover a situation where a bankruptcy
            petition has been filed, but debt service payments are continued.

             CI: The rating CI is reserved for income bonds on which no
            interest is being paid.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period. The D rating will also be used upon the filing of a
            bankruptcy petition if debt service payments are jeopardized.

             Plus (+) or Minus (-): The ratings from AA to CCC may be modified
            by the addition of a plus or minus sign to show relative standing
            within the major rating categories.

             Provisional ratings: The letter "p" indicates that the rating is
            provisional. A provisional rating assumes the successful
            completion of the project being financed by the debt being rated
            and indicates that payment of debt service requirements is largely
            or entirely dependent upon the successful and timely completion of
            the project. This rating, however, while addressing credit quality
            after completion of the project, makes no comment on the
            likelihood of, or the risk of default upon failure of, such
            completion. The investor should exercise his own judgment with
            respect to such likelihood and risk.

             r: The "r" is attached to highlight derivative, hybrid, and
            certain other obligations that S&P believes may experience high
            volatility or high variability in expected returns due to non-
            credit risks. Examples of such

                                                                  Prospectus A-3
<PAGE>

            obligations are: securities whose principal or interest return is
            indexed to equities, commodities, or currencies; certain swaps and
            options; and interest only and principal only mortgage securities.

             The absence of an "r" symbol should not be taken as an indication
            that an obligation will exhibit no volatility or variability in
            total return.

             N.R.: Not rated.

             Debt obligations of issuers outside the United States and its
            territories are rated on the same basis as domestic corporate and
            municipal issues. The ratings measure the creditworthiness of the
            obligor but do not take into account currency exchange and related
            uncertainties.

Commercial  A Standard & Poor's commercial paper rating is a current
Paper       assessment of the likelihood of timely payment of debt having an
Rating      original maturity of no more than 365 days. Ratings are graded
Definitions into several categories, ranging from A for the highest quality
            obligations to D for the lowest. These categories are as follows:

             A-1: This highest category indicates that the degree of safety
            regarding timely payment is strong. Those issues determined to
            possess extremely strong safety characteristics are denoted with a
            plus sign (+) designation.

             A-2: Capacity for timely payment on issues with this designation
            is satisfactory. However, the relative degree of safety is not as
            high as for issues designated A-1.

             A-3: Issues carrying this designation have adequate capacity for
            timely payment. They are, however, more vulnerable to the adverse
            effects of changes in circumstances than obligations carrying the
            higher designations.

             B: Issues rated B are regarded as having only speculative
            capacity for timely payment.

             C: This rating is assigned to short-term debt obligations with a
            doubtful capacity for payment.

             D: Debt rated D is in payment default. The D rating category is
            used when interest payments or principal payments are not made on
            the date due, even if the applicable grace period has not expired,
            unless S&P believes that such payments will be made during such
            grace period.

             A commercial paper rating is not a recommendation to purchase,
            sell or hold a security inasmuch as it does not comment as to
            market price or suitability for a particular investor. The ratings
            are based on current information furnished to Standard & Poor's by
            the issuer or obtained from other sources it considers reliable.
            Standard & Poor's does not perform an audit in connection with any
            rating and may, on occasion, rely on unaudited financial
            information. The ratings may be changed, suspended, or withdrawn
            as a result of changes in or unavailability of such information.

A-4  PIMCO Variable Insurance Trust
<PAGE>

            -------------------------------------------------------------------
PIMCO       INVESTMENT ADVISER AND ADMINISTRATOR
Variable    PIMCO, 840 Newport Center Drive, Suite 300, Newport Beach, CA
Insurance   92660
Trust

            -------------------------------------------------------------------
            CUSTODIAN
            State Street Bank & Trust Co., 801 Pennsylvania, Kansas City, MO
            64105

            -------------------------------------------------------------------
            TRANSFER AGENT
            National Financial Data Services, 330 W. 9th Street, 4th Floor,
            Kansas City, MO 64105

            -------------------------------------------------------------------
            INDEPENDENT ACCOUNTANTS
            PricewaterhouseCoopers LLP, 1055 Broadway, Kansas City, MO 64105

            -------------------------------------------------------------------
            LEGAL COUNSEL
            Dechert Price & Rhoads, 1775 Eye Street N.W., Washington, D.C.
            20006

            -------------------------------------------------------------------
<PAGE>

The Trust's Statement of Additional Information ("SAI") and annual and
semi-annual reports to shareholders include additional information about the
Portfolios. The SAI and the financial statements included in the Portfolios'
most recent annual report to shareholders are incorporated by reference into
this Prospectus, which means they are part of this Prospectus for legal
purposes. The Portfolios' annual report discusses the market conditions and
investment strategies that significantly affected each Portfolio's performance
during its last fiscal year.

You may get free copies of any of these materials, request other information
about a Portfolio, or make shareholder inquiries by calling the Trust at
1-800-987-4626 or by writing to:

PIMCO Variable Insurance Trust
840 Newport Center Drive
Suite 300
Newport Beach, CA 92660

You may review and copy information about the Trust, including its SAI, at the
Securities and Exchange Commission's public reference room in Washington, D.C.
You may call the Commission at 1-800-SEC-0330 for information about the
operation of the public reference room. You may also access reports and other
information about the trust on the Commission's Web site at www.sec.gov. You may
get copies of this information, with payment of a duplication fee, by writing
the Public Reference Section of the Commission, Washington, D.C. 20549-0102. You
may need to refer to the Trust's file number under the Investment Company Act,
which is 811-8399.


                             [LOGO OF PIMCO FUNDS]

PIMCO Funds

840 Newport Center Drive
Suite 300
Newport Beach, CA 92660



© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission