VANGUARD FIXED INCOME SECURITIES FUND INC
497, 1998-05-28
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<PAGE>   1
 
================================================================================
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
                                   FORM N-1A
                   REGISTRATION STATEMENT (NO. 2-47371) UNDER
                           THE SECURITIES ACT OF 1933
                          PRE-EFFECTIVE AMENDMENT NO.
                        POST-EFFECTIVE AMENDMENT NO. 46
                                      AND
 
              REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY
                                  ACT OF 1940
                                AMENDMENT NO. 47
 
                             VANGUARD FIXED INCOME
                             SECURITIES FUND, INC.
               (EXACT NAME OF REGISTRANT AS SPECIFIED IN CHARTER)
 
                             100 VANGUARD BOULEVARD
                             MALVERN, PA 19355-0741
                    (ADDRESS OF PRINCIPAL EXECUTIVE OFFICE)
 
                  REGISTRANT'S TELEPHONE NUMBER (610) 669-1000
 
                         RAYMOND J. KLAPINSKY, ESQUIRE
                                 P.O. BOX 2600
                             VALLEY FORGE, PA 19482
 
            IT IS HEREBY REQUESTED THAT THIS FILING BECOME EFFECTIVE
             ON MAY 29, 1998 PURSUANT TO PARAGRAPH (b) OF RULE 485.
 
                 APPROXIMATE DATE OF PROPOSED PUBLIC OFFERING:
  As soon as practicable after this Registration Statement becomes effective.
 
     WE HAVE ELECTED TO REGISTER AN INDEFINITE NUMBER OF SHARES PURSUANT TO
REGULATION 24f-2 UNDER THE INVESTMENT COMPANY ACT OF 1940. WE FILED OUR RULE
24f-2 NOTICE FOR THE YEAR ENDED JANUARY 31, 1998 ON MAY 1, 1998.
 
================================================================================
<PAGE>   2
 
                  VANGUARD FIXED INCOME SECURITIES FUND, INC.
 
                             CROSS REFERENCE SHEET
 
<TABLE>
<CAPTION>
                             FORM N-1A
                            ITEM NUMBER                                      LOCATION IN PROSPECTUS
<C>           <S>                                                     <C>
  Item 1.     Cover Page...........................................   Cover Page
  Item 2.     Synopsis.............................................   Fund Expenses
  Item 3.     Condensed Financial Information......................   Financial Highlights; Yield and Total
                                                                      Return
  Item 4.     General Description of Registrant....................   Highlights; Investment Objective;
                                                                      Investment Limitations; Investment
                                                                      Policies; Investment Risks; General
                                                                      Information
  Item 5.     Management of the Fund...............................   Management of the Fund; Investment
                                                                      Advisers; General Information
 Item 5A.     Management's Discussion of Fund Performance..........   Herein incorporated by reference to
                                                                      Registrant's Report to Shareholders
                                                                      dated January 31, 1998 filed with the
                                                                      Securities and Exchange Commission's
                                                                      EDGAR system on April 1, 1998
  Item 6.     Capital Stock and Other Securities...................   Opening an Account and Purchasing
                                                                      Shares; Selling Your Shares; The
                                                                      Share Price of each Portfolio;
                                                                      Dividends, Capital Gains and Taxes;
                                                                      General Information
  Item 7.     Purchase of Securities Being Offered.................   Cover Page; Opening an Account and
                                                                      Purchasing Shares
  Item 8.     Redemption or Repurchase.............................   Selling Your Shares
  Item 9.     Pending Legal Proceedings............................   Not Applicable
                             FORM N-1A                                        LOCATION IN STATEMENT
                            ITEM NUMBER                                     OF ADDITIONAL INFORMATION
 Item 10.     Cover Page...........................................   Cover Page
 Item 11.     Table of Contents....................................   Cover Page
 Item 12.     General Information and History......................   The Fund; Investment Objective and
                                                                      Policies
 Item 13.     Investment Objective and Policies....................   Investment Objective and Policies;
                                                                      Investment Limitations
 Item 14.     Management of the Registrant.........................   Management of the Fund; Investment
                                                                      Advisory Services
 Item 15.     Control Persons and Principal Holders of
              Securities...........................................   Not Applicable
 Item 16.     Investment Advisory and Other Services...............   Management of the Fund; Investment
                                                                      Advisory Services
 Item 17.     Brokerage Allocation.................................   Portfolio Transactions
 Item 18.     Capital Stock and Other Securities...................   Not Applicable
 Item 19.     Purchase, Redemption and Pricing of Securities Being
              Offered..............................................   Purchase of Shares; Redemption of
                                                                      Shares
 Item 20.     Tax Status...........................................   Not Applicable
 Item 21.     Underwriters.........................................   Not Applicable
 Item 22.     Calculation of Performance Data......................   Yield and Total Return
 Item 23.     Financial Statements.................................   Financial Statements
</TABLE>
<PAGE>   3
 
================================================================================
 
[VANGUARD FIXED INCOME SECURITIES FUND LOGO]      A Member of The Vanguard Group
================================================================================
 
PROSPECTUS -- MAY 29, 1998
- --------------------------------------------------------------------------------
 
NEW ACCOUNT INFORMATION: INVESTOR INFORMATION DEPARTMENT -- 1-800-662-7447
(SHIP)
- --------------------------------------------------------------------------------
 
SHAREHOLDER ACCOUNT SERVICES: CLIENT SERVICES DEPARTMENT -- 1-800-662-2739
(CREW)
- --------------------------------------------------------------------------------
 
   
INVESTMENT
OBJECTIVE
AND POLICIES          Vanguard Fixed Income Securities Fund, Inc. (the "Fund")
                      is an open-end diversified investment company that seeks
                      to provide investors with a high level of current income
                      consistent with the maintenance of principal and
                      liquidity. The Fund consists of nine distinct Portfolios,
                      each of which invests in fixed income securities within
                      prescribed maturity and credit quality standards. This
                      prospectus pertains to each of the Fund's Portfolios,
                      except the High Yield Corporate Portfolio, which is
                      offered in a separate prospectus. There is no assurance
                      that any of the Fund's Portfolios will achieve its stated
                      objective. Shares of the Fund are neither insured nor
                      guaranteed by any agency of the U.S. Government, including
                      the FDIC.
    
- --------------------------------------------------------------------------------
 
OPENING AN
ACCOUNT               To open a regular (non-retirement) account, please
                      complete and return the Account Registration Form. If you
                      need assistance in completing this Form, please call the
                      Investor Information Department. To open an Individual
                      Retirement Account (IRA), please use a Vanguard IRA
                      Adoption Agreement. To obtain a copy of this form, call
                      1-800-662-7447, Monday through Friday, from 8:00 a.m. to
                      9:00 p.m. and Saturday, from 9:00 a.m. to 4:00 p.m.
                      (Eastern time). The minimum initial investment is $3,000
                      per Portfolio or $1,000 for Uniform Gifts/Transfers to
                      Minors Act accounts. The Fund is offered on a no-load
                      basis (i.e., there are no sales commissions or 12b-1
                      fees). However, the Fund incurs expenses for investment
                      advisory, management, administrative, and distribution
                      services.
- --------------------------------------------------------------------------------
 
ABOUT THIS
PROSPECTUS            This Prospectus is designed to set forth concisely the
                      information you should know about the Fund before you
                      invest. It should be retained for future reference. A
                      "Statement of Additional Information" containing
                      additional information about the Fund has been filed with
                      the Securities and Exchange Commission. This Statement is
                      dated May 29, 1998 and has been incorporated by reference
                      into this Prospectus. A copy may be obtained without
                      charge by writing to the Fund, calling the Investor
                      Information Department at 1-800-662-7447, or visiting the
                      Securities and Exchange Commission's website
                      (www.sec.gov).
- --------------------------------------------------------------------------------
 
TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                Page                                          Page                                          Page
<S>                            <C>         <C>                               <C>         <C>                               <C>
Highlights....................   2         Investment Limitations...........   25        SHAREHOLDER GUIDE
Fund Expenses.................   5         Management of the Fund...........   25        Opening an Account and
Financial Highlights..........   6         Investment Advisers..............   26        Purchasing Shares................   32
Yield and Total Return........   11        Dividends, Capital Gains                      When Your Account Will Be
FUND INFORMATION                           and Taxes........................   29        Credited.........................   36
Investment Objective..........   11        The Share Price of Each                       Selling Your Shares..............   36
Investment Policies...........   11        Portfolio........................   30        Exchanging Your Shares...........   39
Investment Risks..............   16        General Information..............   31        Important Information About
Who Should Invest.............   19                                                      Telephone Transactions...........   41
Implementation of Policies....   20                                                      Transferring Registration........   41
                                                                                         Other Vanguard Services..........   42
</TABLE>
 
- --------------------------------------------------------------------------------
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION, NOR HAS THE SECURITIES AND EXCHANGE COMMISSION PASSED UPON
THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY
IS A CRIMINAL OFFENSE.
- --------------------------------------------------------------------------------
<PAGE>   4
 
                                   HIGHLIGHTS
 
OBJECTIVE AND
POLICIES              The Fund is a no-load, open-end diversified investment
                      company that seeks to provide investors with a high level
                      of income consistent with the maintenance of principal and
                      liquidity. The Fund consists of nine distinct Portfolios,
                      each of which invests in fixed income securities within
                      prescribed maturity and quality standards. There is no
                      assurance that the Fund will achieve its stated
                      objective.                                         PAGE 11
- --------------------------------------------------------------------------------
 
NINE SEPARATE
PORTFOLIOS            The investment characteristics of each Portfolio are
                      summarized in the chart below. As illustrated, the Fund
                      consists of three short-term Portfolios, three
                      intermediate-term Portfolios, two long-term Portfolios,
                      and a high-risk Portfolio investing in low-quality
                      bonds.                                             PAGE 11
 
<TABLE>
                              PORTFOLIO SUMMARY
- -----------------------------------------------------------------------------
                                         PRIMARY            EXPECTED
             PORTFOLIO                 INVESTMENTS      AVERAGE MATURITY
<S>                                <C>                  <C>               <C>
- -----------------------------------------------------------------------------
  Short-Term U.S. Treasury         U.S. Treasury bonds      1-3 years
  Short-Term Federal                 U.S. Government        1-3 years
                                      agency bonds
  Short-Term Corporate+             Investment grade        1-3 years
                                     corporate bonds
- -----------------------------------------------------------------------------
  Intermediate-Term U.S. Treasury  U.S. Treasury bonds     5-10 years
  GNMA                                GNMA mortgage       Intermediate*
                                      certificates
  Intermediate-Term Corporate       Investment grade       5-10 years
                                     corporate bonds
- -----------------------------------------------------------------------------
  Long-Term U.S. Treasury          U.S. Treasury bonds     15-30 years
  Long-Term Corporate               Investment grade       15-25 years
                                     corporate bonds
- -----------------------------------------------------------------------------
  High Yield Corporate**            Speculative grade     Intermediate*
                                     corporate bonds
- -----------------------------------------------------------------------------
</TABLE>
 
 * While neither the GNMA nor the High Yield Corporate Portfolios observe
   specific maturity guidelines, each is expected to maintain an
   intermediate-term average weighted maturity.
 ** The High Yield Corporate Portfolio is offered by a separate prospectus,
    which may be obtained by calling 1-800-662-7447.
 + This Prospectus offers Short-Term Corporate Portfolio's Investor Shares.
- --------------------------------------------------------------------------------
 
                                        2
<PAGE>   5
 
RISK
CHARACTERISTICS       Investors in the Fund are exposed to four types of risk
                      from fixed income securities. (1) INTEREST RATE RISK is
                      the potential for fluctuations in bond prices due to
                      changing interest rates. (2) INCOME RISK is the potential
                      for a decline in a Portfolio's income due to falling
                      market interest rates. (3) CREDIT RISK is the possibility
                      that a bond issuer will fail to make timely payments of
                      either interest or principal to a Portfolio. (4)
                      PREPAYMENT RISK (for mortgage-backed securities) or CALL
                      RISK (for corporate bonds) is the likelihood that, during
                      periods of falling interest rates, securities with high
                      stated interest rates will be prepaid (or "called") prior
                      to maturity, requiring a Portfolio to invest the proceeds
                      at generally lower interest rates.
 
                      The following chart summarizes interest rate, credit,
                      income and prepayment/call risks for each of the eight
                      Portfolios of the Fund offered by this Prospectus. As
                      shown, interest rate risk should be low for the three
                      short-term Portfolios, moderate for the three
                      intermediate-term Portfolios, and high for the two
                      long-term Portfolios. PAGE 16
 
<TABLE>
                                                          RISK SUMMARY
                               ------------------------------------------------------------------
                                                       INTEREST   INCOME   CREDIT    PREPAYMENT/
                                      PORTFOLIO        RATE RISK   RISK     RISK      CALL RISK
                               <S>                     <C>        <C>     <C>        <C>
                               ------------------------------------------------------------------
                                 Short-Term U.S.          Low      High   Negligible  Negligible
                                    Treasury
                                 Short-Term Federal       Low      High   Very Low       Low
                                 Short-Term Corporate     Low      High      Low      Negligible
                               ------------------------------------------------------------------
                                 Intermediate-Term      Medium    Medium  Negligible  Negligible
                                    U.S. Treasury
                                 GNMA                   Medium    Medium  Negligible     High
                                 Intermediate-Term      Medium    Medium     Low         Low
                                    Corporate
                               ------------------------------------------------------------------
                                 Long-Term U.S.          High      Low    Negligible  Negligible
                                    Treasury
                                 Long-Term Corporate     High      Low       Low        Medium
                               ------------------------------------------------------------------
</TABLE>
 
- --------------------------------------------------------------------------------
 
THE VANGUARD
GROUP                 The Fund is a member of The Vanguard Group of Investment
                      Companies, a group of more than 30 investment companies
                      with more than 95 distinct investment portfolios and total
                      assets in excess of $370 billion. The Vanguard Group, Inc.
                      ("Vanguard"), a subsidiary jointly owned by the Vanguard
                      funds, provides all corporate management, administrative,
                      distribution, and shareholder accounting services on an
                      at-cost basis to the funds in the Group. As a result,
                      Vanguard's operating expenses are substantially lower than
                      those of the mutual fund industry.                 PAGE 25
- --------------------------------------------------------------------------------
 
INVESTMENT
ADVISERS              Wellington Management Company, LLP serves as investment
                      adviser to the GNMA and Long-Term Corporate Portfolios.
                      Vanguard's Fixed Income Group provides investment advisory
                      services on an at-cost basis to the three Short-Term
                      Portfolios, the two Intermediate-Term Portfolios and the
                      Long-Term U.S. Treasury Portfolio.
                                                                         PAGE 26
- --------------------------------------------------------------------------------
 
                                        3
<PAGE>   6
 
DIVIDEND POLICY       Each Portfolio declares a dividend each business day based
                      on its ordinary income. Dividends are paid on the first
                      business day of each month. Net capital gains (excess of
                      long- and short-term capital gains over capital losses),
                      if any, will be distributed annually. Dividends and
                      capital gains distributions may be received in cash or
                      reinvested in additional shares.                   PAGE 29
- --------------------------------------------------------------------------------
 
TAXES                 Dividends paid by the Fund's Portfolios are generally
                      subject to federal, state and local income taxes. However,
                      it is expected that most of the income paid by the
                      Short-Term, Intermediate-Term, and Long-Term U.S. Treasury
                      Portfolios, and a meaningful portion of the income from
                      the Short-Term Federal Portfolio, will be attributable to
                      U.S. Treasury and other "direct" Government obligations.
                      Such income may be exempt from state and local taxes,
                      depending on state and local tax laws. Any capital gains
                      distributions from a Portfolio are subject to federal
                      income tax, as well as any applicable state and local
                      taxes. A sale of shares -- whether by outright redemption,
                      checkwriting redemption or an exchange -- is a taxable
                      event and may result in a capital gain or loss.    PAGE 29
- --------------------------------------------------------------------------------
 
PURCHASING
SHARES                You may purchase shares by mail, wire, or exchange from
                      another Vanguard Portfolio. The minimum initial investment
                      is $3,000 per Portfolio ($1,000 for Individual Retirement
                      Accounts and Uniform Gifts/Transfers to Minors Act
                      accounts); the minimum for subsequent investments is $100.
                      There are no sales commissions or 12b-1 fees.      PAGE 32
- --------------------------------------------------------------------------------
 
SELLING SHARES        You may redeem shares of each Portfolio by mail, telephone
                      or check. Telephone redemption proceeds may be received by
                      mail or by wire. There is no charge for redemptions,
                      except for wire withdrawals under $5,000, which are
                      subject to a $5 charge. (Your bank may also impose a fee
                      upon receipt of a wire.) Each Portfolio's share price is
                      expected to fluctuate, and at the time of redemption may
                      be more or less than at the time of initial purchase,
                      resulting in a gain or loss.                       PAGE 36
- --------------------------------------------------------------------------------
 
SERVICES TO
SHAREHOLDERS          The Fund offers free checkwriting services (minimum $250
                      per check) for easy access to your account balance.   PAGE
                      36
 
                      The Fund also offers other special services: Fund Express,
                      for electronic transfers between the Fund and your bank
                      account; and Tele-Account, for 24-hour telephone access to
                      your Fund account balance and certain transactions.   PAGE
                      42
- --------------------------------------------------------------------------------
 
   
SPECIAL
CONSIDERATIONS        (1) Each Portfolio, except the Short-Term Federal
                      Portfolio, may invest a portion of its assets in bond
                      (interest rate) futures contracts and options. Each
                      Portfolio may hold restricted securities. The Short-Term
                      Corporate, Intermediate-Term Corporate and Long-Term
                      Corporate Portfolios may invest in securities of foreign
                      issuers.                                           PAGE 21
    
 
                      (2) Each Portfolio may lend its securities.        PAGE 22
- --------------------------------------------------------------------------------
 
                                        4
<PAGE>   7
 
FUND EXPENSES         The following table illustrates ALL expenses and fees that
                      you would incur as a shareholder of the Fund. These
                      expenses and fees are based upon those incurred for the
                      fiscal year ended January 31, 1998.
 
<TABLE>
<CAPTION>
                                                 SHORT-TERM                                            INTERMEDIATE-
                                                    U.S.            SHORT-TERM        SHORT-TERM           TERM
                                                  TREASURY           FEDERAL           CORPORATE       U.S. TREASURY
       SHAREHOLDER TRANSACTION EXPENSES           PORTFOLIO         PORTFOLIO          PORTFOLIO         PORTFOLIO
- ----------------------------------------------------------------------------------------------------------------------
<S>                                             <C>             <C>                  <C>             <C>
Sales Load Imposed on Purchases...............      None               None              None              None
Sales Load Imposed on Reinvested Dividends....      None               None              None              None
Redemption Fees*..............................      None               None              None              None
Exchange Fees.................................      None               None              None              None
</TABLE>
 
<TABLE>
<CAPTION>
                                          SHORT-TERM         SHORT-TERM        SHORT-TERM     INTERMEDIATE-TERM
                                         U.S. TREASURY        FEDERAL           CORPORATE       U.S. TREASURY
    ANNUAL FUND OPERATING EXPENSES         PORTFOLIO         PORTFOLIO         PORTFOLIO**        PORTFOLIO
- ---------------------------------------------------------------------------------------------------------------
<S>                                      <C>             <C>                  <C>             <C>
Management & Administrative Expenses...      0.21%              0.21%             0.23%             0.21%
Investment Advisory Fees...............      0.02               0.01              0.01              0.01
12b-1 Fees.............................      None               None              None              None
Other Expenses
  Distribution Costs...................      0.03%              0.03%             0.03%             0.03%
  Miscellaneous Expenses...............      0.01               0.02              0.01              0.02
                                         ----------      ------------         ----------      ------------
Total Other Expenses...................      0.04               0.05              0.04              0.05
                                         ----------      ------------         ----------      ------------
         TOTAL OPERATING EXPENSES......      0.27%              0.27%             0.28%             0.27%
                                         ===========     =============        ===========     =============
</TABLE>
 
<TABLE>
<CAPTION>
                                                                  INTERMEDIATE-        LONG-TERM
                                                                       TERM              U.S.            LONG-TERM
                                                    GNMA            CORPORATE          TREASURY          CORPORATE
       SHAREHOLDER TRANSACTION EXPENSES           PORTFOLIO         PORTFOLIO          PORTFOLIO         PORTFOLIO
- ----------------------------------------------------------------------------------------------------------------------
<S>                                             <C>             <C>                  <C>             <C>
Sales Load Imposed on Purchases...............      None               None              None              None
Sales Load Imposed on Reinvested Dividends....      None               None              None              None
Redemption Fees*..............................      None               None              None              None
Exchange Fees.................................      None               None              None              None
</TABLE>
 
<TABLE>
<CAPTION>
                                                                  INTERMEDIATE-        LONG-TERM
                                                                       TERM              U.S.            LONG-TERM
                                                    GNMA            CORPORATE          TREASURY          CORPORATE
        ANNUAL FUND OPERATING EXPENSES            PORTFOLIO         PORTFOLIO          PORTFOLIO         PORTFOLIO
- ----------------------------------------------------------------------------------------------------------------------
<S>                                             <C>             <C>                  <C>             <C>
Management & Administrative Expenses..........      0.26%              0.20%             0.21%             0.26%
Investment Advisory Fees......................      0.01               0.01              0.01              0.03
12b-1 Fees....................................      None               None              None              None
Other Expenses
  Distribution Costs..........................      0.02%              0.03%             0.03%             0.02%
  Miscellaneous Expenses......................      0.02               0.02              0.02              0.01
                                                ----------      ------------         ----------      ------------
Total Other Expenses..........................      0.04               0.05              0.05              0.03
                                                ----------      ------------         ----------      ------------
         TOTAL OPERATING EXPENSES.............      0.31%              0.26%             0.27%             0.32%
                                                ===========     =============        ===========     =============
</TABLE>
 
 * Wire redemptions of less than $5,000 are subject to a $5 processing fee.
** Expenses shown are for Short-Term Corporate Portfolio's Investor Shares.
 
                                        5
<PAGE>   8
 
   
                      The purpose of this table is to assist you in
                      understanding the various costs and expenses that you
                      would bear directly or indirectly as a shareholder in the
                      Fund.
    
 
                      The following example illustrates the expenses that you
                      would incur on a $1,000 investment over various periods,
                      assuming (1) a 5% annual rate of return and (2) redemption
                      at the end of each period.
 
<TABLE>
<CAPTION>
                                                                            1         3         5         10
                                                                           YEAR     YEARS     YEARS     YEARS
                                                                          ------   -------   -------   --------
                               <S>                                        <C>      <C>       <C>       <C>
                               Short-Term U.S. Treasury Portfolio.......    $3       $ 9       $15       $34
                               Short-Term Federal Portfolio.............    $3       $ 9       $15       $34
                               Short-Term Corporate
                                 Portfolio -- Investor Shares...........    $3       $ 9       $16       $36
                               Intermediate-Term U.S. Treasury
                                 Portfolio..............................    $3       $ 9       $15       $34
                               Intermediate-Term Corporate Portfolio....    $3       $ 8       $15       $33
                               GNMA Portfolio...........................    $3       $10       $17       $39
                               Long-Term U.S. Treasury Portfolio........    $3       $ 9       $15       $34
                               Long-Term Corporate Portfolio............    $3       $10       $18       $41
</TABLE>
 
                      THIS EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF
                      PAST OR FUTURE EXPENSES OR PERFORMANCE. ACTUAL EXPENSES
                      MAY BE HIGHER OR LOWER THAN THOSE SHOWN.
- --------------------------------------------------------------------------------
 
FINANCIAL
HIGHLIGHTS            The following financial highlights for a share outstanding
                      throughout each period have been derived from financial
                      statements which were audited by Price Waterhouse LLP,
                      independent accountants, whose reports on the financial
                      statements which contain this information were
                      unqualified. This information should be read in
                      conjunction with the Fund's financial statements and notes
                      thereto, which, together with the remaining portions of
                      the Fund's 1998 Annual Report to Shareholders, are
                      incorporated by reference in the Statement of Additional
                      Information and in this Prospectus, and which appear,
                      along with the reports of Price Waterhouse LLP, in the
                      Fund's 1998 Annual Report to Shareholders. For a more
                      complete discussion of the Fund's performance, please see
                      the Fund's 1998 Annual Report to Shareholders which may be
                      obtained without charge by writing to the Fund or by
                      calling our Investor Information Department at
                      1-800-662-7447.
 
                                        6
<PAGE>   9
 
<TABLE>
<CAPTION>
                                                   ----------------------------------------------------------------------
                                                                     SHORT-TERM U.S. TREASURY PORTFOLIO
                                                   ----------------------------------------------------------------------
                                                                 YEAR ENDED JANUARY 31,
                                                   ---------------------------------------------------   OCT. 28, 1991.+
                                                    1998     1997     1996     1995     1994     1993    TO JAN. 31, 1992
<S>                                                <C>      <C>      <C>      <C>      <C>      <C>      <C>
- -------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF PERIOD.............  $10.16   $10.36   $ 9.89   $10.41   $10.41   $10.12        $10.00
                                                   ------   ------   ------   ------   ------   ------   -----------
INVESTMENT OPERATIONS
  Net Investment Income..........................    .590     .586     .625     .532     .486     .528          .140
  Net Realized and Unrealized Gain (Loss) on
    Investments..................................    .110    (.200)    .470    (.500)    .079     .332          .120
                                                   ------   ------   ------   ------   ------   ------   -----------
    TOTAL FROM INVESTMENT OPERATIONS.............    .700     .386    1.095     .032     .565     .860          .260
- -------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment Income...........   (.590)   (.586)   (.625)   (.532)   (.486)   (.528)        (.140)
  Distributions from Realized Capital Gains......      --       --       --    (.020)   (.079)   (.042)           --
                                                   ------   ------   ------   ------   ------   ------   -----------
    TOTAL DISTRIBUTIONS..........................   (.590)   (.586)   (.625)   (.552)   (.565)   (.570)        (.140)
- -------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD...................  $10.27   $10.16   $10.36   $ 9.89   $10.41   $10.41        $10.12
=========================================================================================================================
TOTAL RETURN.....................................    7.11%    3.89%   11.37%    0.40%    5.54%    8.74%         2.60%
=========================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Period (Millions).............  $1,009   $  970   $  919   $  754   $  729   $  526        $  102
Ratio of Total Expenses to Average Net Assets....    0.27%    0.25%    0.27%    0.28%    0.26%    0.26%         0.26%*
Ratio of Net Investment Income to Average Net
  Assets.........................................    5.80%    5.77%    6.14%    5.33%    4.64%    5.12%         5.22%*
Portfolio Turnover Rate..........................      83%      86%      93%     126%      86%      71%           40%
</TABLE>
 
* Annualized.
+ Commencement of operations.
 
<TABLE>
<CAPTION>
                                         ---------------------------------------------------------------------------------------
                                                                      SHORT-TERM FEDERAL PORTFOLIO
                                         ---------------------------------------------------------------------------------------
                                                                         YEAR ENDED JANUARY 31,
                                         ---------------------------------------------------------------------------------------
                                          1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF YEAR.....  $10.11   $10.28   $ 9.79   $10.38   $10.38   $10.31   $10.08   $ 9.89   $ 9.78   $10.05
                                         ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
INVESTMENT OPERATIONS
  Net Investment Income................    .611     .615     .601     .550     .522     .609     .720     .801     .842     .817
  Net Realized and Unrealized Gain
    (Loss) on Investments..............    .080    (.170)    .490    (.580)    .110     .232     .307     .190     .110    (.270)
                                         ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL FROM INVESTMENT OPERATIONS...    .691     .445    1.091    (.030)    .632     .841    1.027     .991     .952     .547
- --------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment
    Income.............................   (.611)   (.615)   (.601)   (.550)   (.522)   (.609)   (.720)   (.801)   (.842)   (.817)
  Distributions from Realized Capital
    Gains..............................      --       --       --    (.010)   (.110)   (.162)   (.077)      --       --       --
                                         ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL DISTRIBUTIONS................   (.611)   (.615)   (.601)   (.560)   (.632)   (.771)   (.797)   (.801)   (.842)   (.817)
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR...........  $10.19   $10.11   $10.28   $ 9.79   $10.38   $10.38   $10.31   $10.08   $ 9.89   $ 9.78
================================================================================================================================
TOTAL RETURN...........................    7.06%    4.51%   11.43%   (0.21)%   6.23%    8.49%   10.59%   10.46%   10.09%    5.66%
================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year (Millions).....  $1,460   $1,348   $1,402   $1,474   $1,936   $1,688   $1,274     $508     $228     $159
Ratio of Total Expenses to Average
  Net Assets...........................    0.27%    0.25%    0.27%    0.28%    0.26%    0.27%    0.26%    0.30%    0.28%    0.32%
Ratio of Net Investment Income to
  Average Net Assets...................    6.04%    6.09%    5.93%    5.53%    4.98%    5.88%    6.98%    8.06%    8.59%    8.50%
Portfolio Turnover Rate................      94%      57%      74%      57%      49%      70%     111%     141%     133%     228%
</TABLE>
 
                                        7
<PAGE>   10
 
<TABLE>
<CAPTION>
                                     -------------------------------------------------------------------------------------------
                                                          SHORT-TERM CORPORATE PORTFOLIO -- INVESTOR SHARES
                                     -------------------------------------------------------------------------------------------
                                                                       YEAR ENDED JANUARY 31,
                                     -------------------------------------------------------------------------------------------
                                      1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                  <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR.............................  $10.75   $10.94   $10.40   $10.94   $10.99   $10.88   $10.50   $10.34   $10.23   $10.43
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
INVESTMENT OPERATIONS
  Net Investment Income............    .664     .663     .671     .596     .605     .695     .804     .876     .895     .833
  Net Realized and Unrealized Gain
    (Loss) on Investments..........    .120    (.190)    .540    (.540)    .049     .275     .380     .160     .110    (.200)
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL FROM INVESTMENT
      OPERATIONS...................    .784     .473    1.211     .056     .654     .970    1.184    1.036    1.005     .633
- --------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net
    Investment Income..............   (.664)   (.663)   (.671)   (.596)   (.605)   (.695)   (.804)   (.876)   (.895)   (.833)
  Distributions from Realized
    Capital Gains..................      --       --       --       --    (.099)   (.165)      --       --       --       --
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL DISTRIBUTIONS............   (.664)   (.663)   (.671)   (.596)   (.704)   (.860)   (.804)   (.876)   (.895)   (.833)
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR.......  $10.87   $10.75   $10.94   $10.40   $10.94   $10.99   $10.88   $10.50   $10.34   $10.23
================================================================================================================================
TOTAL RETURN.......................    7.53%    4.52%   11.95%    0.60%    6.11%    9.29%   11.70%   10.47%   10.18%    6.31%
================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions).......................  $4,709   $4,531   $3,873   $2,924   $3,573   $2,811   $1,911     $829     $597     $493
Ratio of Total Expenses to Average
  Net Assets.......................    0.28%    0.25%    0.27%    0.28%    0.26%    0.27%    0.26%    0.31%    0.28%    0.34%
Ratio of Net Investment Income to
  Average Net Assets...............    6.17%    6.18%    6.23%    5.66%    5.48%    6.33%    7.44%    8.48%    8.70%    8.17%
Portfolio Turnover Rate............      45%      45%      62%      69%      61%      71%      99%     107%     121%     165%
</TABLE>
 
<TABLE>
<CAPTION>
                                           ----------------------------------------------------------------------------
                                                            INTERMEDIATE-TERM U.S. TREASURY PORTFOLIO
                                           ----------------------------------------------------------------------------
                                                           YEAR ENDED JANUARY 31,
                                           ------------------------------------------------------    OCT. 28, 1991+ TO
                                            1998     1997      1996     1995      1994      1993       JAN. 31, 1992
<S>                                        <C>      <C>       <C>      <C>       <C>       <C>       <C>                <C>
- ----------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF PERIOD.....  $10.37   $10.90    $ 9.76   $ 10.82   $ 10.79   $10.19          $10.00
                                           ------   ------    ------    ------    ------   ------    ------------
INVESTMENT OPERATIONS
  Net Investment Income..................    .647     .649      .662      .603      .617     .676            .170
  Net Realized and Unrealized Gain (Loss)
    on Investments.......................    .430    (.530)    1.140    (1.033)     .443     .617            .190
                                           ------   ------    ------    ------    ------   ------    ------------
    TOTAL FROM INVESTMENT OPERATIONS.....   1.077     .119     1.802     (.430)    1.060    1.293            .360
- ----------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment Income...   (.647)   (.649)    (.662)    (.603)    (.617)   (.676)          (.170)
  Distributions from Realized Capital
    Gains................................      --       --        --     (.027)    (.413)   (.017)             --
                                           ------   ------    ------    ------    ------   ------    ------------
    TOTAL DISTRIBUTIONS..................   (.647)   (.649)    (.662)    (.630)   (1.030)   (.693)          (.170)
- ----------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD...........  $10.80   $10.37    $10.90   $  9.76   $ 10.82   $10.79          $10.19
======================================================================================================================
TOTAL RETURN.............................   10.78%    1.28%    18.96%    (3.90)%   10.09%   13.14%           3.59%
======================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Period (Millions).....  $1,595   $1,279    $1,226      $848    $1,007     $673             $190
Ratio of Total Expenses to Average Net
  Assets.................................    0.27%    0.25%     0.28%     0.28%     0.26%    0.26%           0.26%*
Ratio of Net Investment Income to Average
  Net Assets.............................    6.19%    6.26%     6.34%     6.05%     5.55%    6.44%           6.47%*
Portfolio Turnover Rate..................      30%      42%       56%      128%      118%     123%             32%
</TABLE>
 
* Annualized.
+ Commencement of operations.
 
                                        8
<PAGE>   11
 
<TABLE>
<CAPTION>
                                     -------------------------------------------------------------------------------------------
                                                                           GNMA PORTFOLIO
                                     -------------------------------------------------------------------------------------------
                                                                       YEAR ENDED JANUARY 31,
                                     -------------------------------------------------------------------------------------------
                                      1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                  <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR.............................  $10.23   $10.45   $ 9.71   $10.39   $10.50   $10.25   $ 9.85   $ 9.54   $ 9.34   $ 9.69
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
INVESTMENT OPERATIONS
  Net Investment Income............    .718     .727     .734     .693     .641     .778     .831     .855     .878     .882
  Net Realized and Unrealized Gain
    (Loss) on Investments..........    .253    (.220)    .740    (.673)   (.110)    .250     .400     .310     .200    (.350)
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL FROM INVESTMENT
      OPERATIONS...................    .971     .507    1.474     .020     .531    1.028    1.231    1.165    1.078     .532
- --------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net
    Investment Income..............   (.718)   (.727)   (.734)   (.693)   (.641)   (.778)   (.831)   (.855)   (.878)   (.882)
  Distributions from Realized
    Capital Gains..................   (.003)      --       --    (.007)      --       --       --       --       --       --
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL DISTRIBUTIONS............   (.721)   (.727)   (.734)   (.700)   (.641)   (.778)   (.831)   (.855)   (.878)   (.882)
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR.......  $10.48   $10.23   $10.45   $ 9.71   $10.39   $10.50   $10.25   $ 9.85   $ 9.54   $ 9.34
================================================================================================================================
TOTAL RETURN.......................    9.86%    5.15%   15.64%    0.36%    5.18%   10.40%   13.00%   12.85%   11.98%    5.80%
================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions).......................  $8,894   $7,400   $6,998   $5,851   $7,043   $7,167   $5,207   $2,711   $2,128   $1,907
Ratio of Total Expenses to Average
  Net Assets.......................    0.31%    0.27%    0.29%    0.30%    0.28%    0.29%    0.29%    0.34%    0.31%    0.35%
Ratio of Net Investment Income to
  Average Net Assets...............    6.97%    7.16%    7.22%    7.04%    6.19%    7.38%    8.22%    8.95%    9.25%    9.35%
Portfolio Turnover Rate............       3%      12%       7%      35%       2%       7%       1%       1%       9%       8%
</TABLE>
 
<TABLE>
<CAPTION>
                                                              -------------------------------------------------------
                                                                       INTERMEDIATE-TERM CORPORATE PORTFOLIO
                                                              -------------------------------------------------------
                                                                    YEAR ENDED JANUARY 31,
                                                              -----------------------------------   NOV. 1, 1993+ TO
                                                               1998     1997      1996      1995      JAN. 31, 1994
<S>                                                           <C>      <C>       <C>       <C>      <C>               <C>
- ---------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF PERIOD........................  $ 9.72   $10.17    $ 9.07    $10.04        $10.00
                                                              ------   ------    ------    ------   ------------
INVESTMENT OPERATIONS
  Net Investment Income.....................................    .638     .639      .658      .587          .125
  Net Realized and Unrealized Gain (Loss) on Investments....    .321    (.430)    1.100     (.970)         .040
                                                              ------   ------    ------    ------   ------------
    TOTAL FROM INVESTMENT OPERATIONS........................    .959     .209     1.758     (.383)         .165
- ---------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment Income......................   (.638)   (.639)    (.658)    (.587)        (.125)
  Distributions from Realized Capital Gains.................   (.011)   (.020)       --        --            --
                                                              ------   ------    ------    ------   ------------
    TOTAL DISTRIBUTIONS.....................................   (.649)   (.659)    (.658)    (.587)        (.125)
- ---------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD..............................  $10.03   $ 9.72    $10.17    $ 9.07        $10.04
=====================================================================================================================
TOTAL RETURN................................................   10.24%    2.29%    19.94%    (3.73)%        1.66%
=====================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Period (Millions)........................    $899     $592      $424      $163            $85
Ratio of Total Expenses to Average Net Assets...............    0.26%    0.25%     0.28%     0.28%         0.25%*
Ratio of Net Investment Income to Average Net Assets........    6.51%    6.61%     6.70%     6.46%         5.11%*
Portfolio Turnover Rate.....................................      69%      85%       78%       97%           74%
</TABLE>
 
* Annualized.
+ Commencement of operations.
 
                                        9
<PAGE>   12
 
<TABLE>
<CAPTION>
                                      -------------------------------------------------------------------------------------------
                                                                   LONG-TERM U.S. TREASURY PORTFOLIO
                                      -------------------------------------------------------------------------------------------
                                                                        YEAR ENDED JANUARY 31,
                                      -------------------------------------------------------------------------------------------
                                       1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                   <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR..............................   $9.84   $10.73    $9.23   $10.75   $10.04   $10.14    $9.74    $9.53    $9.28    $9.49
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
INVESTMENT OPERATIONS
  Net Investment Income.............    .643     .655     .669     .665     .685     .733     .763     .776     .781     .778
  Net Realized and Unrealized Gain
    (Loss) on Investments...........    .950    (.877)   1.725   (1.401)    .886     .600     .400     .210     .250    (.210)
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL FROM INVESTMENT
      OPERATIONS....................   1.593    (.222)   2.394    (.736)   1.571    1.333    1.163     .986    1.031     .568
- ---------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment
    Income..........................   (.643)   (.655)   (.669)   (.665)   (.685)   (.733)   (.763)   (.776)   (.781)   (.778)
  Distributions from Realized
    Capital Gains...................      --    (.013)   (.225)   (.119)   (.176)   (.700)      --       --       --       --
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL DISTRIBUTIONS.............   (.643)   (.668)   (.894)   (.784)   (.861)  (1.433)   (.763)   (.776)   (.781)   (.778)
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE,
  END OF YEAR.......................  $10.79    $9.84   $10.73    $9.23   $10.75   $10.04   $10.14    $9.74    $9.53    $9.28
=================================================================================================================================
TOTAL RETURN........................   16.85%   (1.85)%  26.72%   (6.68)%  16.09%   14.12%   12.44%   11.00%   11.33%    6.43%
=================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions)........................  $1,061     $898     $916     $671     $829     $874     $833     $722     $456     $172
Ratio of Total Expenses to Average
  Net Assets........................    0.27%    0.25%    0.27%    0.28%    0.26%    0.27%    0.26%    0.30%    0.28%    0.36%
Ratio of Net Investment Income to
  Average Net Assets................    6.38%    6.66%    6.57%    7.02%    6.44%    7.26%    7.72%    8.29%    8.08%    8.46%
Portfolio Turnover Rate.............      18%      31%     105%      85%       7%     170%      89%     147%      83%     387%
</TABLE>
 
   
<TABLE>
<CAPTION>
                                      -------------------------------------------------------------------------------------------
                                                                     LONG-TERM CORPORATE PORTFOLIO
                                      -------------------------------------------------------------------------------------------
                                                                        YEAR ENDED JANUARY 31,
                                      -------------------------------------------------------------------------------------------
                                       1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                   <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR..............................   $8.71    $9.43    $8.18    $9.36    $9.04    $8.63    $8.02    $8.00    $7.91    $8.11
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
INVESTMENT OPERATIONS
  Net Investment Income.............    .613     .619     .627     .617     .632     .680     .706     .720     .732     .741
  Net Realized and Unrealized Gain
    (Loss) on Investments...........    .685    (.566)   1.250   (1.108)    .579     .561     .610     .020     .090    (.200)
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL FROM INVESTMENT
      OPERATIONS....................   1.298     .053    1.877    (.491)   1.211    1.241    1.316     .740     .822     .541
- ---------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment
    Income..........................   (.613)   (.619)   (.627)   (.617)   (.632)   (.680)   (.706)   (.720)   (.732)   (.741)
  Distributions from Realized
    Capital Gains...................   (.075)   (.154)      --    (.072)   (.259)   (.151)      --       --       --       --
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL DISTRIBUTIONS.............   (.688)   (.773)   (.627)   (.689)   (.891)   (.831)   (.706)   (.720)   (.732)   (.741)
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR........   $9.32    $8.71    $9.43    $8.18    $9.36    $9.04    $8.63    $8.02    $8.00    $7.91
=================================================================================================================================
TOTAL RETURN........................   15.52%    0.86%   23.64%   (5.12)%  13.83%   15.06%   17.09%    9.81%   10.67%    7.13%
=================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions)........................  $3,720   $3,324   $3,376   $2,607   $3,166   $2,763   $1,992   $1,254     $954     $734
Ratio of Total Expenses to Average
  Net Assets........................    0.32%    0.28%    0.31%    0.32%    0.30%    0.31%    0.31%    0.37%    0.34%    0.38%
Ratio of Net Investment Income to
  Average Net Assets................    6.87%    7.06%    7.03%    7.37%    6.71%    7.68%    8.46%    9.16%    9.07%    9.40%
Portfolio Turnover Rate.............      33%      30%      49%      43%      77%      50%      72%      62%      70%      60%
</TABLE>
    
 
- --------------------------------------------------------------------------------
 
                                       10
<PAGE>   13
 
YIELD AND
TOTAL RETURN          From time to time a Portfolio may advertise its yield and
                      total return. Both yield and total return figures are
                      based on historical earnings and are not intended to
                      indicate future performance. The "total return" of a
                      Portfolio refers to the average annual compounded rates of
                      return over one- , five- and ten-year periods or for the
                      life of the Portfolio (as stated in the advertisement)
                      that would equate an initial amount invested at the
                      beginning of a stated period to the ending redeemable
                      value of the investment, assuming the reinvestment of all
                      dividends and capital gains distributions.
 
                      In accordance with industry guidelines set forth by the
                      U.S. Securities and Exchange Commission, the "30-day
                      yield" of a Portfolio is calculated by dividing net
                      investment income per share earned during a 30-day period
                      by the net asset value per share on the last day of the
                      period. Net investment income includes interest and
                      dividend income earned on the Portfolio's securities; it
                      is net of all expenses and all recurring and nonrecurring
                      charges that have been applied to all shareholder
                      accounts. The yield calculation assumes that net
                      investment income earned over 30 days is compounded
                      monthly for six months and then annualized. Methods used
                      to calculate advertised yields are standardized for all
                      stock and bond mutual funds. However, these methods differ
                      from the accounting methods used by a Portfolio to
                      maintain its books and records, and so the advertised
                      30-day yield may not fully reflect the income paid to an
                      investor's account or the yield reported in the
                      Portfolio's Reports to Shareholders.
 
                      Additionally, a Portfolio may compare its performance to
                      that of the Lehman Aggregate Bond Index, and may advertise
                      its duration, a measure of a Portfolio's sensitivity to
                      interest rate changes.
- --------------------------------------------------------------------------------
 
INVESTMENT
OBJECTIVE
THE FUND SEEKS TO
PROVIDE A HIGH LEVEL
OF CURRENT INCOME     The Fund is an open-end diversified investment company.
                      The objective of the Fund is to provide investors with a
                      high level of current income consistent with the
                      maintenance of principal and liquidity.
 
                      The Fund consists of nine distinct Portfolios, each of
                      which invests in fixed income securities within prescribed
                      maturity and quality standards. There is no assurance that
                      the Fund will achieve its stated objective.
 
                      The investment objective for the Fund is not fundamental
                      and so may be changed by the Board of Directors without
                      shareholder approval. Any such change could result in the
                      Fund having investment objectives different from the
                      objectives which a shareholder considered appropriate at
                      the time of investment in the Fund. However, shareholders
                      would be notified prior to any material change in the
                      Fund's objective.
- --------------------------------------------------------------------------------
 
INVESTMENT
POLICIES              While all of the Fund's Portfolios invest in fixed income
                      securities, the individual Portfolios vary substantially
                      in terms of the type, credit quality, and average maturity
                      of the securities in which they invest. The Fund is
                      managed without regard to tax ramifications.
 
                      IMPORTANT NOTE: Five of the Portfolios invest in U.S.
                      Treasury or U.S. Government agency securities to minimize
                      credit risk. Examples of the Government agencies and
                      instrumentalities whose securities may be purchased by
                      these Portfolios include the
 
                                       11
<PAGE>   14
 
                      Federal Home Loan Mortgage Corporation, the Small Business
                      Administration, the Government Export Trust and the
                      Overseas Private Investment Corporation. Government
                      securities may be backed by (i) the full faith and credit
                      of the United States; (ii) the particular Government
                      agency's ability to borrow directly from the Treasury;
                      (iii) some other type of United States support; or (iv)
                      the credit of the issuing agency, only. As described
                      below, each of the five Portfolios which invests in U.S.
                      Treasury or U.S. Government agency securities is required
                      to invest a specified percentage of its assets in
                      securities backed by the full faith and credit of the
                      United States. WHILE U.S. TREASURY OR GOVERNMENT AGENCY
                      SECURITIES PROVIDE SUBSTANTIAL PROTECTION AGAINST CREDIT
                      RISK, THEY DO NOT PROTECT INVESTORS AGAINST PRICE CHANGES
                      DUE TO CHANGING INTEREST RATES. THE MARKET VALUES OF
                      GOVERNMENT SECURITIES ARE NOT GUARANTEED AND WILL
                      FLUCTUATE. See "Investment Risks" for additional
                      information on these and other important risks.
 
THREE PORTFOLIOS
INVEST IN SHORT-TERM
BONDS                 Three Portfolios of the Fund invest in short-term bonds.
                      The SHORT-TERM U.S. TREASURY PORTFOLIO invests at least
                      85% of its assets in short-term securities backed by the
                      full faith and credit of the U.S. Government. Also, at
                      least 65% of the Portfolio's assets will be invested in
                      U.S. Treasury bills, notes and bonds. In an effort to
                      minimize fluctuations in market value, the Short-Term U.S.
                      Treasury Portfolio is expected to maintain a
                      dollar-weighted average maturity between one and three
                      years.
 
                      The balance of the Short-Term U.S. Treasury Portfolio's
                      assets may be invested in U.S. Treasury or U.S. Government
                      agency securities, as well as in repurchase agreements
                      collateralized by such securities. The Portfolio may also
                      invest in bond (interest rate) futures and options to a
                      limited extent. See "Implementation of Policies" for a
                      description of these investment practices of the
                      Portfolio.
 
                      The SHORT-TERM FEDERAL PORTFOLIO invests primarily in U.S.
                      Government agency securities, which are debt obligations
                      issued or guaranteed by agencies or instrumentalities of
                      the U.S. Government. Such "agency" securities may not be
                      backed by the "full faith and credit" of the U.S.
                      Government. The Portfolio may also invest in U.S. Treasury
                      securities, as well as in repurchase agreements
                      collateralized by U.S. Treasury or U.S. Government agency
                      securities. In an effort to minimize fluctuations in
                      market value, the Short-Term Federal Portfolio is expected
                      to maintain a dollar weighted-average maturity between 1
                      and 3 years. See "Implementation of Policies" for a
                      description of these investment practices of the
                      Portfolio.
 
                      The SHORT-TERM CORPORATE PORTFOLIO invests in the
                      following investment grade fixed income securities:
 
                      (1) Short-term and intermediate-term corporate debt
                          securities;
 
                      (2) U.S. Treasury and U.S. Government agency obligations;
 
                      (3) Obligations issued by state and municipal governments
                          and their agencies and instrumentalities;
 
                      (4) Bank obligations, including certificates of deposit
                          and bankers' acceptances;
 
                                       12
<PAGE>   15
 
                      (5) Commercial paper; and
 
                      (6) Repurchase agreements collateralized by these
                          securities.
 
   
                      Investment grade corporate debt securities are those rated
                      a minimum of Baa3 by Moody's Investors Service, Inc.
                      ("Moody's") or BBB- by Standard & Poor's Corporation
                      ("Standard & Poor's"). Investment grade commercial paper
                      is rated A-1 or better by Standard & Poor's or Prime-1 by
                      Moody's, or, if unrated, issued by a corporation having an
                      outstanding unsecured debt issue rated A or better by
                      Moody's or Standard & Poor's. At least 70% of the
                      Short-Term Corporate Portfolio's assets will be invested
                      in debt securities rated a minimum of A3 by Moody's or A-
                      by Standard & Poor's, and not more than 30% of the
                      Portfolio's assets may be invested in debt securities
                      rated Baa by Moody's or BBB by Standard & Poor's.
                      Securities rated Baa or BBB are considered medium grade
                      obligations. Interest payments and principal are regarded
                      as adequate for the present, but certain protective
                      elements found in higher-rated bonds may be lacking. Such
                      bonds lack outstanding investment characteristics and have
                      speculative characteristics.
    
 
                      In the event that a security held by the Portfolio is
                      downgraded, the Portfolio may continue to hold such
                      security until such time as the adviser deems it
                      advantageous to dispose of the security.
 
                      In an effort to minimize fluctuations in market value, the
                      Short-Term Corporate Portfolio is expected to maintain a
                      dollar-weighted average maturity between 1 and 3 years.
                      The Short-Term Corporate Portfolio may also hold
                      asset-backed securities, as well as securities of foreign
                      issuers provided such securities are denominated in U.S.
                      dollars. In addition, the Portfolio may invest in bond
                      (interest rate) futures and options to a limited extent.
                      See "Implementation of Policies" for a description of
                      these investment practices of the Portfolio.
 
THREE PORTFOLIOS
INVEST IN
INTERMEDIATE-TERM
BONDS                 The INTERMEDIATE-TERM U.S. TREASURY PORTFOLIO invests at
                      least 85% of its assets in intermediate-term securities
                      backed by the full faith and credit of the U.S.
                      Government. Also, at least 65% of the Portfolio's assets
                      will be invested in U.S. Treasury bills, notes and bonds.
                      The dollar-weighted average maturity of the Portfolio is
                      expected to range from 5 to 10 years.
 
                      The balance of the Portfolio's assets may be invested in
                      U.S. Treasury or U.S. Government agency securities, as
                      well as in repurchase agreements collateralized by such
                      securities. The Portfolio may also invest in bond
                      (interest rate) futures and options to a limited extent.
                      See "Implementation of Policies" for a description of
                      these investment practices of the Portfolio.
 
                      The GNMA PORTFOLIO invests at least 80% of its assets in
                      Government National Mortgage Association ("GNMA" or
                      "Ginnie Mae") pass-through certificates. The balance of
                      the Portfolio's assets may be invested in other U.S.
                      Treasury or U.S. Government agency securities, as well as
                      in repurchase agreements collateralized by such
                      securities. The Portfolio may also invest in bond
                      (interest rate) futures and options to a limited extent
                      and real estate mortgage conduits ("REMICs"). See
                      "Implementation of Policies" for a description of these
                      investment practices of the Portfolio.
 
                                       13
<PAGE>   16
 
                      GNMA pass-through certificates are mortgage-backed
                      securities representing part ownership of a pool of
                      mortgage loans. Monthly mortgage payments of both interest
                      and principal "pass through" from homeowners to
                      certificate investors, such as the GNMA Portfolio. The
                      GNMA Portfolio reinvests the principal portion in
                      additional securities and distributes the interest portion
                      as income to the Portfolio's shareholders. Under normal
                      circumstances, GNMA certificates are expected to provide
                      higher yields than U.S. Treasury securities of comparable
                      maturity.
 
                      The mortgage loans underlying GNMA certificates -- issued
                      by lenders such as mortgage bankers, commercial banks, and
                      savings and loan associations -- are either insured by the
                      Federal Housing Administration (FHA) or guaranteed by the
                      Veterans Administration (VA). Each pool of mortgage loans
                      must also be approved by GNMA, a U.S. Government
                      corporation within the U.S. Department of Housing and
                      Urban Development. Once GNMA approval is obtained, the
                      timely payment of interest and principal on each
                      underlying mortgage loan is guaranteed by the "full faith
                      and credit" of the U.S. Government.
 
                      Although stated maturities on GNMA certificates generally
                      range from 25 to 30 years, effective maturities are
                      usually much shorter due to the prepayment of the
                      underlying mortgages by homeowners. On average, GNMA
                      certificates are repaid within 12 years and so are
                      classified as intermediate-term securities.
 
                      The INTERMEDIATE-TERM CORPORATE PORTFOLIO invests in a
                      diversified portfolio of investment grade corporate and
                      Government bonds. Under normal circumstances, at least 65%
                      of the Portfolio's assets are invested in straight debt
                      corporate bonds rated a minimum of Baa3 by Moody's or BBB-
                      by Standard & Poor's at the time of purchase.
                      Additionally, at least 80% of the Portfolio's assets will
                      normally be invested in a combination of investment grade
                      corporate bonds and securities of the U.S. Government and
                      its agencies and instrumentalities. The Intermediate-Term
                      Corporate Portfolio is expected to maintain a
                      dollar-weighted average maturity between 5 and 10 years.
 
                      The preponderance of the Portfolio's holdings will be
                      classified in the top three credit-rating categories.
                      Specifically, at least 70% of the Portfolio's assets will
                      be invested in the following securities:
 
                      (1) Short-term and intermediate-term corporate debt
                          securities which at the time of purchase are rated a
                          minimum of A3 by Moody's or A- by Standard & Poor's;
 
                      (2) Securities issued by the U.S. Government, state and
                          municipal governments or their agencies and
                          instrumentalities;
 
                      (3) Commercial paper of companies having, at the time of
                          purchase, outstanding debt securities rated as
                          described in (1) or commercial paper rated P-1 or P-2
                          by Moody's or rated A-1 or A-2 by Standard & Poor's;
                          and
 
                      (4) Short-term fixed income securities held as cash
                          reserves, including U.S. Treasury or U.S. Government
                          agency securities, certificates of deposit, bankers'
                          acceptances, or repurchase agreements collateralized
                          by these securities.
 
                                       14
<PAGE>   17
 
                      Up to 30% of the Intermediate-Term Corporate Portfolio's
                      assets may be invested in straight debt securities rated
                      Baa by Moody's or BBB by Standard & Poor's (see page 13
                      for a description of these ratings), and in preferred
                      stocks and convertible securities. In the event that a
                      security held by the Portfolio is downgraded, the
                      Portfolio may continue to hold such security until such
                      time as the adviser deems it to be advantageous to dispose
                      of the security.
 
                      The Intermediate-Term Corporate Portfolio may also hold
                      asset-backed securities, as well as securities of foreign
                      issuers provided such securities are denominated in U.S.
                      dollars. The Portfolio may also invest in bond (interest
                      rate) futures and options to a limited extent. See
                      "Implementation of Policies" for a description of these
                      investment practices of the Portfolio.
 
TWO PORTFOLIOS INVEST
IN LONG-TERM BONDS    The LONG-TERM U.S. TREASURY PORTFOLIO invests at least 85%
                      of its assets in long-term securities backed by the full
                      faith and credit of the U.S. Government. Also, at least
                      65% of the Portfolio's assets will be invested in U.S.
                      Treasury bills, notes and bonds. The dollar-weighted
                      average maturity of the Portfolio is expected to range
                      from 15 to 30 years.
 
                      The balance of the Portfolio's assets may be invested in
                      U.S. Treasury or U.S. Government agency securities, as
                      well as in repurchase agreements collateralized by such
                      securities. The Portfolio may also invest in bond
                      (interest rate) futures and options to a limited extent.
                      See "Implementation of Policies" for a description of
                      these investment practices of the Portfolio.
 
                      The LONG-TERM CORPORATE PORTFOLIO invests in a diversified
                      portfolio of investment grade corporate and Government
                      bonds. Under normal circumstances, at least 65% of the
                      Portfolio's assets are invested in straight debt corporate
                      bonds rated a minimum of Baa3 by Moody's or BBB- by
                      Standard & Poor's at the time of purchase. Additionally,
                      at least 80% of the Portfolio's assets will normally be
                      invested in a combination of investment grade corporate
                      bonds and securities of the U.S. Government and its
                      agencies and instrumentalities. The dollar-weighted
                      average maturity of the Portfolio is expected to range
                      from 15 to 25 years.
 
                      The preponderance of the Portfolio's holdings will be
                      classified in the top three credit-rating categories.
                      Specifically, at least 70% of the Portfolio's assets will
                      be invested in the following securities:
 
                      (1) Straight debt corporate securities which at the time
                          of purchase are rated a minimum of A3 by Moody's or A-
                          by Standard & Poor's;
 
                      (2) Securities issued by the U.S. Government or its
                          agencies and instrumentalities;
 
                      (3) Commercial paper of companies having, at the time of
                          purchase, outstanding debt securities rated as
                          described in (1) or commercial paper rated P-1 or P-2
                          by Moody's or rated A-1 or A-2 by Standard & Poor's;
                          and
 
                      (4) Short-term fixed income securities held as cash
                          reserves, including U.S. Treasury or U.S. Government
                          agency securities, certificates of deposit, bankers'
                          acceptances, or repurchase agreements collateralized
                          by these securities.
                                       15
<PAGE>   18
 
                      Up to 30% of the Long-Term Corporate Portfolio's assets
                      may be invested in straight debt securities rated Baa by
                      Moody's or BBB by Standard & Poor's (see page 13 for a
                      description of these ratings), and in preferred stocks and
                      convertible securities. In addition, not more than 25% of
                      the Portfolio's assets may be invested in GNMA
                      certificates or other mortgage-backed securities. In the
                      event that a security held by the Portfolio is downgraded,
                      the Portfolio may continue to hold such security until
                      such time as the adviser deems it to be advantageous to
                      dispose of the security.
 
                      The Long-Term Corporate Portfolio may also hold
                      asset-backed securities, as well as U.S.
                      dollar-denominated debt securities issued by foreign
                      governments, their agencies and instrumentalities,
                      supranational entities and companies located outside the
                      U.S. The Portfolio may also invest in bond (interest rate)
                      futures and options to a limited extent. See
                      "Implementation of Policies" for a description of these
                      investment practices of the Portfolio.
 
                                                 * * *
 
                      The Fund is responsible for voting the shares of all
                      securities it holds.
- --------------------------------------------------------------------------------
 
INVESTMENT RISKS
THE PORTFOLIOS ARE
SUBJECT PRIMARILY
TO INTEREST RATE,
INCOME, CREDIT AND
MANAGER RISK          As mutual funds investing in fixed income securities, the
                      Portfolios of the Fund are subject primarily to interest
                      rate, income, credit and manager risk. INTEREST RATE RISK
                      is the potential for a decline in bond prices due to
                      rising interest rates. In general, bond prices vary
                      inversely with interest rates. When interest rates rise,
                      bond prices generally fall. Conversely, when interest
                      rates fall, bond prices generally rise. The change in
                      price depends on several factors, including the bond's
                      maturity date. In general, bonds with longer maturities
                      are more sensitive to changes in interest rates than bonds
                      with shorter maturities.
 
                      These principles of interest rate risk also apply to U.S.
                      Treasury and U.S. Government agency securities. As with
                      other bond investments, U.S. Government securities will
                      rise and fall in value as interest rates change. A
                      SECURITY BACKED BY THE U.S. TREASURY OR THE FULL FAITH AND
                      CREDIT OF THE UNITED STATES IS GUARANTEED ONLY AS TO THE
                      TIMELY PAYMENT OF INTEREST AND PRINCIPAL WHEN HELD TO
                      MATURITY. THE CURRENT MARKET PRICES FOR SUCH SECURITIES
                      ARE NOT GUARANTEED AND WILL FLUCTUATE.
 
                                       16
<PAGE>   19
 
                      As an illustration of interest rate risk, the charts below
                      depict the effect of a one and two percentage point change
                      in interest rates on three bonds of varying maturities:
 
                       PERCENT CHANGE IN THE PRICE OF A PAR BOND YIELDING 7.5%
 
<TABLE>
<CAPTION>
                                                                 1 PERCENTAGE POINT   1 PERCENTAGE POINT
                                                                    INCREASE IN          DECREASE IN
                                       STATED MATURITY             INTEREST RATES       INTEREST RATES
                               -------------------------------   ------------------   ------------------
                               <S>                               <C>                  <C>
                               Short-Term (2.5 years)                  - 2.2%                + 2.3%
                               Intermediate-Term (10 years)            - 6.6%                + 7.3%
                               Long-Term (20 years)                    - 9.5%                +11.1%
</TABLE>
 
<TABLE>
<CAPTION>
                                                                 2 PERCENTAGE POINT   2 PERCENTAGE POINT
                                                                    INCREASE IN          DECREASE IN
                                       STATED MATURITY             INTEREST RATES       INTEREST RATES
                               -------------------------------   ------------------   ------------------
                               <S>                               <C>                  <C>
                               Short-Term (2.5 years)                  - 4.3%                + 4.6%
                               Intermediate-Term (10 years)            -12.7%                +15.2%
                               Long-Term (20 years)                    -17.8%                +24.1%
</TABLE>
 
                      These charts are intended to provide you with guidelines
                      for determining the degree of interest rate risk you may
                      be willing to assume. The yield and price changes shown
                      should not be taken as representative of a Portfolio's
                      current or future yield or expected changes in a
                      Portfolio's share price.
 
                      INCOME RISK is the potential for a decline in a
                      Portfolio's income due to falling market interest rates.
                      In relative terms, income risk will be higher for the
                      Fund's shorter-term Portfolios and lower for the Fund's
                      longer-term Portfolios.
 
                      Each Portfolio of the Fund is also subject to credit risk.
                      CREDIT RISK, also known as default risk, is the
                      possibility that a bond issuer will fail to make timely
                      payments of interest or principal to a Portfolio. The
                      credit risk of a Portfolio depends on the quality of its
                      investments. Reflecting their higher risks, lower-quality
                      bonds generally offer higher yields (all other factors
                      being equal).
 
                      Besides interest rate risk and credit risk, investors are
                      exposed to PREPAYMENT RISK in the GNMA Portfolio and CALL
                      RISK in the Long-Term Corporate Portfolio.
 
                      Finally, the investment advisers manage the Portfolios
                      according to the traditional methods of "active"
                      investment management, which involve the buying and
                      selling of securities based upon economic, financial and
                      market analysis and investment judgment. MANAGER RISK
                      refers to the possibility that a Portfolio's investment
                      adviser may fail to execute the Portfolio's investment
                      strategy effectively. As a result, a Portfolio may fail to
                      achieve its stated objective.
 
THREE SHORT-TERM
PORTFOLIOS PROVIDE
MODERATE EXPOSURE TO
INTEREST RATE RISK    Interest rate risk for the SHORT-TERM U.S TREASURY
                      PORTFOLIO, the SHORT-TERM FEDERAL PORTFOLIO, and the
                      SHORT-TERM CORPORATE PORTFOLIO should be modest. Because
                      of their short-term average weighted maturities, the three
                      short-term Portfolios are expected to exhibit low to
                      moderate price fluctuations as interest rates change.
 
                                       17
<PAGE>   20
 
                      The three Portfolios differ principally in terms of credit
                      quality and potential yield. For the Short-Term U.S.
                      Treasury Portfolio, credit risk should be negligible. In
                      relative terms, credit risk will be slightly higher for
                      the Short-Term Federal Portfolio because of its holdings
                      of U.S. Government agency securities. (Even though they
                      carry top (Aaa) credit ratings, "agency" obligations are
                      not explicitly guaranteed by the U.S. Government and so
                      are perceived as somewhat riskier than comparable Treasury
                      bonds.)
 
                      With its corporate bond holdings, the Short-Term Corporate
                      Portfolio offers the highest exposure to credit risk of
                      the three short-term Portfolios. However, because of the
                      Portfolio's well-diversified holdings and emphasis on
                      high-quality bonds, overall credit risk should still be
                      quite low.
 
INTEREST RATE RISK
FOR THE THREE
INTERMEDIATE-TERM
PORTFOLIOS WILL BE
HIGHER                The three intermediate-term Portfolios are exposed to a
                      higher degree of interest rate risk than the three
                      short-term Portfolios. The INTERMEDIATE-TERM U.S. TREASURY
                      PORTFOLIO, the GNMA PORTFOLIO and the INTERMEDIATE-TERM
                      CORPORATE PORTFOLIO are expected to exhibit moderate to
                      high price fluctuations as interest rates change. Credit
                      risk, however, should be minimal for the Intermediate-Term
                      U.S. Treasury and the GNMA Portfolios, as both Portfolios
                      invest primarily in "full faith and credit" securities of
                      the U.S. Government.
 
                      Due to its investments in corporate securities, credit
                      risk associated with the Intermediate-Term Corporate
                      Portfolio will be higher than for the other two
                      intermediate-term Portfolios. However, the
                      Intermediate-Term Corporate Portfolio's diversification
                      and quality of investments should help limit credit risk.
 
                      The GNMA Portfolio is unique among the Fund's Portfolios
                      in its exposure to prepayment risk. Prepayment risk is the
                      possibility that, as interest rates fall, homeowners are
                      more likely to refinance their home mortgages. When home
                      mortgages are refinanced, the principal on GNMA
                      certificates held by the Portfolio is "prepaid" earlier
                      than expected. The GNMA Portfolio must then reinvest the
                      unanticipated principal in new GNMA certificates, just at
                      a time when interest rates on new mortgage investments are
                      falling.
 
                      Prepayment risk has two important effects on the GNMA
                      Portfolio:
 
                      - When interest rates fall and additional mortgage
                        prepayments must be reinvested at lower interest rates,
                        the income of the GNMA Portfolio will be reduced.
 
                      - When interest rates fall, prices on GNMA securities will
                        not rise as much as comparable Treasury bonds, as bond
                        market investors anticipate an increase in mortgage
                        prepayments and a likely decline in income.
 
                      In part to compensate for this risk, the GNMA Portfolio
                      will generally offer higher yields than a bond portfolio
                      of comparable quality -- such as the Intermediate-Term
                      U.S. Treasury Portfolio.
 
                                       18
<PAGE>   21
 
FOR THE TWO LONG-TERM
PORTFOLIOS, INTEREST
RATE RISK MAY BE
SUBSTANTIAL           The two long-term Portfolios are exposed to substantial
                      interest rate risk. The LONG-TERM U.S. TREASURY PORTFOLIO
                      and the LONG-TERM CORPORATE PORTFOLIO, both of which
                      maintain average maturities in excess of 15 years, may
                      exhibit high to very high price fluctuations due to
                      changing interest rates.
 
                      The main difference between the two Portfolios is credit
                      risk. The Long-Term U.S. Treasury Portfolio invests
                      primarily in "full faith and credit" U.S. Treasury bonds
                      for maximum credit protection, while the Long-Term
                      Corporate Portfolio invests in investment grade corporate
                      bonds for higher yields. Although credit risk for the
                      Long-Term Corporate Portfolio will be somewhat higher,
                      overall credit risk should still be low because of the
                      Portfolio's well-diversified holdings and its emphasis on
                      high-quality bonds.
 
                      An additional risk associated with the Long-Term Corporate
                      Portfolio is call risk. Call risk is the possibility that
                      corporate bonds held by the Portfolio will be repaid prior
                      to maturity. Call provisions, common in many corporate
                      bonds held by the Portfolio, allow bond issuers to redeem
                      bonds prior to maturity (at a specified price). When
                      interest rates are falling, bond issuers often exercise
                      these call provisions, paying off bonds that carry high
                      stated interest rates and often issuing new bonds at lower
                      rates. For the Portfolio, the result would be that bonds
                      with high interest rates are "called" and must be replaced
                      with lower-yielding instruments. In these circumstances,
                      the income of the Portfolio would decline.
 
                      Reflecting these additional credit and call risks, the
                      Long-Term Corporate Portfolio will generally offer higher
                      yields than the Long-Term U.S. Treasury Portfolio.
- --------------------------------------------------------------------------------
 
WHO SHOULD
INVEST
INVESTORS SEEKING
CURRENT INCOME        The Fund is intended for investors who are seeking a high
                      level of current income from their investments. The Fund
                      is also suitable for investors with common stock holdings
                      who are seeking a complementary fixed income investment to
                      create a more diversified and balanced investment mix.
                      Because of potential fluctuations in the share price of
                      the Fund's Portfolios, the Fund may be inappropriate for
                      short-term investors who require maximum stability of
                      principal. Because of the risks associated with bond
                      investments, the Fund is intended to be a long-term
                      investment vehicle and is not designed to provide
                      investors with a means of speculating on short-term bond
                      market movements.
 
                      Investors who engage in excessive account activity
                      generate additional costs which are borne by all of the
                      Fund's shareholders. In order to minimize such costs the
                      Fund has adopted the following policies. The Fund reserves
                      the right to reject any purchase request (including
                      exchange purchases from other Vanguard portfolios) that is
                      reasonably deemed to be disruptive to efficient portfolio
                      management, either because of the timing of the investment
                      or previous excessive trading by the investor.
                      Additionally, the Fund has adopted exchange privilege
                      limitations as described in the section "Exchange
                      Privilege Limitations." Finally, the Fund reserves the
                      right to suspend the offering of its shares.
 
                      You should base your selection of a Portfolio (or
                      Portfolios) of the Fund on your own objectives, risk
                      preferences, and time horizon.
 
                                       19
<PAGE>   22
 
                      Three short-term Portfolios -- the SHORT-TERM U.S.
                      TREASURY PORTFOLIO, SHORT-TERM FEDERAL PORTFOLIO, and
                      SHORT-TERM CORPORATE PORTFOLIO -- are designed for
                      investors who are seeking yields that are more durable and
                      usually higher than those available from money market
                      funds, and who can tolerate modest fluctuations in the
                      value of their investment. The choice among the three is
                      one of credit quality -- U.S. Treasury, U.S. Government
                      agency, or corporate.
 
                      The three intermediate-term Portfolios -- the
                      INTERMEDIATE-TERM U.S. TREASURY PORTFOLIO, the GNMA
                      PORTFOLIO and the INTERMEDIATE-TERM CORPORATE PORTFOLIO --
                      offer high credit quality, higher yields and a steadier
                      income than available from the three short-term
                      Portfolios. Price swings, however, can be substantial. The
                      choice between the three is again one of credit
                      quality -- U.S. Treasury, U.S. Government agency, or
                      corporate -- as well as one of prepayment risk (i.e.,
                      whether you are willing to take on the prepayment risk of
                      the GNMA Portfolio in exchange for generally higher
                      yields).
 
                      The two long-term Portfolios, the LONG-TERM U.S. TREASURY
                      PORTFOLIO and the LONG-TERM CORPORATE PORTFOLIO, are
                      designed for investors seeking high credit quality and
                      steady levels of income, and who can withstand potentially
                      large fluctuations in the market value of their
                      investment. The choice between the two is one of credit
                      quality and call risk. The Long-Term Corporate Portfolio
                      generally offers higher yields than the Long-Term U.S.
                      Treasury Portfolio in exchange for higher credit and call
                      risks.
- --------------------------------------------------------------------------------
 
IMPLEMENTATION
OF POLICIES
EACH PORTFOLIO MAY
INVEST IN REPURCHASE
AGREEMENTS            Each Portfolio of the Fund utilizes a variety of
                      investment practices in pursuit of its objective.
 
                      Each Portfolio of the Fund may invest in repurchase
                      agreements according to the restrictions and limitations
                      set forth in "Investment Policies." A repurchase agreement
                      is a means of investing monies for a short period. In a
                      repurchase agreement, a seller -- a U.S. commercial bank
                      or recognized U.S. securities dealer -- sells securities
                      to a Portfolio and agrees to repurchase the securities at
                      the Portfolio's cost plus interest within a specified
                      period (normally one day). In these transactions, the
                      securities purchased by the Portfolio will have a total
                      value equal to or in excess of the value of the repurchase
                      agreement, and will be held by the Fund's Custodian Bank
                      until repurchased.
 
                      The use of repurchase agreements involves certain risks.
                      For example, if the other party to the agreement defaults
                      on its obligation to repurchase the underlying security at
                      a time when the value of the security has declined, the
                      Portfolio may incur a loss upon disposition of the
                      security. If the other party to the agreement becomes
                      insolvent and subject to liquidation or reorganization
                      under the Bankruptcy Code or other laws, a court may
                      determine that the underlying security is collateral for a
                      loan by the Portfolio and not within the control of the
                      Portfolio. As a result, the Portfolio's ability to realize
                      on such collateral may be automatically stayed. Finally,
                      it is possible that the Portfolio may not be able to
                      substantiate its interest in the underlying security and
                      may be deemed an unsecured creditor of the other party to
                      the
 
                                       20
<PAGE>   23
 
                      agreement. While each Portfolio's management acknowledges
                      these risks, it is expected that they can be controlled
                      through careful monitoring procedures.
 
EACH PORTFOLIO MAY
OWN RESTRICTED OR
ILLIQUID SECURITIES   Each Portfolio of the Fund may own restricted or illiquid
                      securities to a limited extent. Restricted or illiquid
                      securities are securities which are not freely marketable
                      or which are subject to restrictions upon sale under the
                      Securities Act of 1933. Each Portfolio may invest up to
                      15% of its net assets in restricted or illiquid
                      securities. The Fund's Board of Directors may from time to
                      time determine certain restricted securities known as Rule
                      144A securities to be liquid. Such securities will not be
                      subject to the 15% limitation described above.
 
THREE PORTFOLIOS MAY
INVEST IN SECURITIES
OF FOREIGN ISSUERS    The Short-Term Corporate, Intermediate-Term Corporate and
                      Long-Term Corporate Portfolios may hold securities of
                      foreign issuers, but all such securities must be
                      denominated in U.S. dollars. Securities of foreign issuers
                      may trade in U.S. or foreign securities markets.
                      Securities of foreign issuers may involve investment risks
                      that are different from those of domestic issuers. Such
                      risks include the effect of foreign economic policies and
                      conditions, future political and economic developments,
                      and the possible imposition of exchange controls or other
                      foreign governmental restrictions on foreign debt issuers.
                      There may also be less publicly available information
                      about a foreign issuer than a domestic issuer of
                      securities. Foreign issuers are generally not subject to
                      the uniform accounting, auditing and financial reporting
                      standards that apply to domestic issuers. Also, foreign
                      debt markets may be characterized by lower liquidity,
                      greater price volatility, and higher transaction costs.
                      Additionally, it may be difficult to obtain or enforce a
                      legal judgment in a foreign court.
 
MOST PORTFOLIOS MAY
INVEST IN FUTURES
CONTRACTS, OPTIONS,
AND OTHER DERIVATIVE
SECURITIES            Each Portfolio of the Fund, except for the Short-Term
                      Federal Portfolio, may invest in futures contracts and
                      options to a limited extent. Specifically, a Portfolio may
                      enter into futures contracts provided that not more than
                      5% of its assets are required as a futures contract margin
                      deposit; in addition, a Portfolio may enter into futures
                      contracts and options transactions only to the extent that
                      obligations under such contracts or transactions represent
                      not more than 20% of the Portfolio's assets.
 
                      Futures contracts and options may be used for several
                      reasons: to maintain cash reserves while simulating full
                      investment, to facilitate trading, to reduce transaction
                      costs, or to seek higher investment returns when a
                      specific futures contract is priced more attractively than
                      other futures contracts or the underlying security or
                      index. The Portfolios intend to use futures contracts only
                      for bona fide hedging purposes and will not use futures
                      contracts or options for speculative purposes.
 
FUTURES CONTRACTS
AND OPTIONS POSE
CERTAIN RISKS         The primary risks associated with the use of futures
                      contracts and options are: (i) imperfect correlation
                      between the change in market value of the bonds held by a
                      Portfolio and the prices of futures contracts and options;
                      and (ii) possible lack of a liquid secondary market for a
                      futures contract and the resulting inability to close a
                      futures position prior to its maturity date. The risk of
                      imperfect correlation will be minimized by investing only
                      in those contracts whose price fluctuations are expected
                      to resemble those of the Portfolio's underlying
                      securities. The risk that a Portfolio will
 
                                       21
<PAGE>   24
 
                      be unable to close out a futures position will be
                      minimized by entering into such transactions on a national
                      exchange with an active and liquid secondary market.
 
                      The risk of loss in trading futures contracts in some
                      strategies can be substantial, due both to the low margin
                      deposits required and the extremely high degree of
                      leverage involved in futures pricing. As a result, a
                      relatively small price movement in a futures contract may
                      result in immediate and substantial loss (or gain) to the
                      investor. When investing in futures contracts, a Portfolio
                      will segregate cash or other liquid portfolio securities
                      in the amount of the underlying obligation.
 
DERIVATIVE INVESTING  Derivatives are instruments whose value is linked to or
                      derived from an underlying security or index. The most
                      common are futures and options which are described above.
                      Other derivatives include swaps, inverse floaters, IO's
                      (interest only), and PO's (principal only). Derivatives
                      may be traded separately on exchanges or in the
                      over-the-counter market, or they may be imbedded in other
                      securities. The most common imbedded derivative is the
                      call option attached to or imbedded in a callable
                      government or callable corporate bond. The owner of a
                      traditional callable bond holds a combination of a long
                      position in a non-callable bond and a short position in a
                      call option on that bond, i.e. the bond issuer has the
                      right to call the bond away from the holder of the bond.
                      Any of these instruments may also be used individually or
                      in combination to hedge against unfavorable changes in
                      interest rates, or to speculate on anticipated changes in
                      interest rates. Derivatives may be structured with no or a
                      high degree of leverage. When derivatives are used as
                      hedges, the risk incurred is that the derivative
                      instrument's value may change differently than the value
                      of the security being hedged. This "basis risk" is
                      generally lower than the risk associated with an unhedged
                      position in the security being hedged. Some derivatives
                      may entail liquidity risk, i.e. the risk that the
                      instrument cannot be sold at a reasonable price in highly
                      volatile markets. Leveraged derivatives used for
                      speculation are very volatile, and therefore, very risky.
                      However, the Fund's Portfolios will only utilize
                      derivatives for hedging or arbitrage purposes, and not for
                      speculative purposes. Over-the-counter derivatives involve
                      a counterparty risk, i.e. the risk that the individual or
                      institution on the other side of the agreement will not or
                      cannot meet its obligations under the derivative
                      agreement.
 
EACH PORTFOLIO MAY
LEND ITS SECURITIES   Each Portfolio of the Fund may lend its investment
                      securities to qualified institutional investors for either
                      short-term or long-term purposes of realizing additional
                      income. Loans of securities by a Portfolio will be
                      collateralized by cash, letters of credit, or securities
                      issued or guaranteed by the U.S. Government or its
                      agencies. The collateral will equal at least 100% of the
                      current market value of the loaned securities, and such
                      loans may not exceed 33 1/3% of the value of the
                      Portfolio's total assets (including any collateral
                      obtained in connection with such loans).
 
MOST PORTFOLIOS MAY
INVEST IN CMOS        The Short-Term Federal, Short- and Intermediate-Term
                      Corporate and the Short-, Intermediate- and Long-Term U.S.
                      Treasury Portfolios may invest in collateralized mortgage
                      obligations (CMOs), bonds that are collateralized by whole
                      loan mortgages or mortgage pass-through securities. In the
                      case of the Short-Term Federal
 
                                       22
<PAGE>   25
 
   
                      and the Short-, Intermediate- and Long-Term U.S. Treasury
                      Portfolios, only CMOs issued by agencies or
                      instrumentalities of the U.S. Government will be
                      purchased. However, the Short-, Intermediate- and
                      Long-Term Corporate Portfolios may also purchase
                      privately-issued CMOs carrying investment grade ratings.
                      The bonds issued under a CMO structure are divided into
                      groups with varying maturities, and the cash flows
                      generated by the mortgages or mortgage pass-through
                      securities in the collateral pool are used to first pay
                      interest and then pay principal to the CMO bondholders.
                      Under the CMO structure, the repayment of principal among
                      the different groups is prioritized in accordance with the
                      terms of the particular CMO issuance. The "fastest-pay"
                      group of bonds, as specified in the prospectus for the
                      issuance, would initially receive all principal payments.
                      When that group of bonds is retired, the next group or
                      groups, in the sequence, as specified in the prospectus,
                      receive all of the principal payments until all of the
                      groups are retired. Aside from market risk, the primary
                      risk involved in any mortgage security, such as a CMO
                      issuance, is its exposure to prepayment risk. To the
                      extent a particular group of bonds is exposed to this
                      risk, the bondholder is generally compensated in the form
                      of higher yield (see "Investment Risks"). In order to
                      provide security, in addition to the underlying
                      collateral, many CMO issues also include minimum
                      reinvestment rate and minimum sinking-fund guarantees.
                      Typically, the Portfolios will invest in those CMOs that
                      most appropriately reflect their average maturities and
                      market risk profiles. Consequently, the Short-Term
                      Portfolios invest only in CMOs with highly predictable
                      short-term average maturities. Similarly, the
                      Intermediate-Term Portfolios will invest in those CMOs
                      that carry market risks and expected average maturities
                      consistent with intermediate-term bonds, and the Long-Term
                      U.S. Treasury Portfolio will invest in those CMO's that
                      carry market risks and expected average maturities
                      consistent with long-term bonds.
    
 
                      The maturity of some classes of CMOs may be very difficult
                      to predict because any such predictions are highly
                      dependent upon assumptions regarding the prepayments which
                      CMOs may experience. Deviations in the actual prepayments
                      experienced may significantly affect the ultimate maturity
                      of CMOs, and in such an event, the maturity and risk
                      characteristics of CMOs purchased by the Portfolios may be
                      significantly greater or less than intended. The
                      possibility that rising interest rates may cause
                      prepayments to occur at a slower than expected rate is
                      known as extension risk. This particular risk may
                      effectively change a CMO which was considered short- or
                      intermediate-term at the time of purchase into a long-term
                      security. Alternatively, there are certain classes of CMOs
                      that are by design constructed to have highly predictable
                      average maturities. Such CMOs will retain their relative
                      predictability over a broad range of prepayment
                      experience. The Portfolios expect to control extension
                      risk by purchasing these specific classes of CMOs which,
                      in the advisers' opinions, are reasonably predictable.
 
THE GNMA PORTFOLIO
MAY INVEST IN REMICS  The GNMA Portfolio may invest in real estate investment
                      conduits ("REMICs"). A REMIC is a CMO that qualifies for
                      special tax treatment under the Internal Revenue Code and
                      invests in certain mortgages principally secured by
                      interests in real property. Investors may purchase
                      beneficial interests in REMICs, which are known
 
                                       23
<PAGE>   26
 
                      as "regular" interests, or "residual" interests.
                      Guaranteed REMIC pass-through certificates ("REMIC
                      Certificates") issued by FNMA or FHLMC represent
                      beneficial ownership interests in a REMIC trust consisting
                      principally of mortgage loans or FNMA, FHLMC or
                      GNMA-guaranteed mortgage pass-through certificates. For
                      FHLMC REMIC Certificates, FHLMC guarantees the timely
                      payment of interest, and also guarantees the payment of
                      principal as payments are required to be made on the
                      underlying mortgage participation certificates. FNMA REMIC
                      Certificates are issued and guaranteed as to timely
                      distribution of principal and interest by FNMA.
 
FOUR PORTFOLIOS
MAY INVEST IN
ASSET-BACKED
SECURITIES            The Short-Term Federal, Short-Term Corporate,
                      Intermediate-Term Corporate, and Long-Term Corporate
                      Portfolios of the Fund may invest in asset-backed
                      securities. These securities represent partial ownership
                      in pools of consumer or commercial loans--such as mortgage
                      or automobile loans, credit card balances, equipment lease
                      loans, and collateralized bond obligations (bonds backed
                      by other securities).
 
                      Besides being backed by the loans or other assets in the
                      pool, many of these securities come with credit
                      enhancements as additional protection against default.
                      Such credit enhancements could include
                      over-collateralization or insurance coverage provided by a
                      highly rated (usually AAA) institution other than the
                      security's issuer.
 
                      The value of asset-backed securities ultimately depends on
                      whether the borrowers repay the underlying loans, and
                      whether the credit enhancements, if any, are adequate.
                      Despite any credit enhancements, the value of an
                      asset-backed security may fluctuate because of several
                      factors, including:
 
                      - The market's perception of the value of the assets
                        backing the security.
 
                      - The creditworthiness of the agent in charge of
                        collecting loan payments and passing them through to
                        security holders, the firm that originated the loans,
                        and the institution providing any credit insurance or
                        guarantees.
 
                      - The nature of any insurance or other credit
                        enhancements.
 
                      Another risk of asset-backed securities, especially in
                      periods of declining interest rates, is that borrowers may
                      prepay the underlying loans. These prepayments shorten the
                      weighted average life of an asset-backed security and may
                      lower its return.
 
PORTFOLIO TURNOVER
RATES WILL VARY       Although they generally seek to invest for the long term,
                      the Portfolios of the Fund retain the right to sell
                      securities regardless of how long they have been held. It
                      is anticipated that the annual portfolio turnover rate for
                      the GNMA and Long-Term Corporate Portfolios will not
                      exceed 100%. A 100% turnover rate would occur, for
                      example, if all of the securities in a Portfolio were
                      replaced within one year. For the Intermediate-Term and
                      Long-Term U.S. Treasury and the Intermediate-Term
                      Corporate Portfolios, portfolio turnover rates will
                      generally not exceed 200%. For the Short-Term U.S.
                      Treasury, Short-Term Federal, and Short-Term Corporate
                      Portfolios, portfolio turnover rates will be higher due to
                      the short-term maturities of the securities purchased, but
                      are not expected to exceed 300%. A higher portfolio
 
                                       24
<PAGE>   27
 
                      turnover rate will cause a Portfolio to incur additional
                      brokerage costs and may cause a Portfolio to realize a
                      higher level of capital gains or losses.
- --------------------------------------------------------------------------------
 
INVESTMENT
LIMITATIONS
THE FUND HAS ADOPTED
CERTAIN FUNDAMENTAL
LIMITATIONS           Each of the Fund's Portfolios has adopted limitations on
                      some of its investment policies. Some of these limitations
                      are that a Portfolio will not:
 
                      (a) with respect to 75% of its assets, invest more than 5%
                          of the value of its assets in the securities of any
                          single company or purchase more than 10% of the voting
                          securities of any issuer (except for securities issued
                          or guaranteed by the U.S. Government or any of its
                          agencies or instrumentalities);
 
                      (b) invest more than 5% of its assets in the securities of
                          companies that have a continuous operating history of
                          less than three years;
 
                      (c) invest more than 25% of its assets in any one
                          industry, provided that: (i) this limitation does not
                          apply to obligations issued or guaranteed by the U.S.
                          Government or its agencies or instrumentalities; (ii)
                          utility companies will be divided according to their
                          services (for example, gas, gas transmission,
                          electric, electric and gas, and telephone will each be
                          considered a separate industry); and (iii) financial
                          service companies will be classified according to the
                          end users of their services (for example, automobile
                          finance, bank finance, and diversified finance will be
                          considered as separate industries);
 
                      (d) borrow money, except that the Portfolio may borrow
                          from banks (or through reverse repurchase agreements),
                          for temporary or emergency (not leveraging) purposes,
                          including the meeting of redemption requests which
                          might otherwise require the untimely disposition of
                          securities, in an amount not exceeding 15% of the
                          value of the Portfolio's net assets (including the
                          amount borrowed and the value of any outstanding
                          reverse repurchase agreements) at the time the
                          borrowing is made. Whenever borrowings exceed 5% of
                          the value of the Portfolio's net assets, the Portfolio
                          will not make any additional investments; and
 
                      (e) pledge, mortgage or hypothecate its assets to an
                          extent greater than 5% of the value of its total
                          assets.
 
                      A complete list of the Fund's investment limitations can
                      be found in the Statement of Additional Information. These
                      limitations are fundamental and may be changed only by
                      approval of a majority of the Fund's shareholders.
- --------------------------------------------------------------------------------
 
MANAGEMENT OF
THE FUND
VANGUARD ADMINISTERS
AND DISTRIBUTES THE
FUND                  The Fund is a member of The Vanguard Group of Investment
                      Companies, a family of more than 30 investment companies
                      with more than 95 distinct portfolios and total assets in
                      excess of $370 billion. Through their jointly-owned
                      subsidiary, The Vanguard Group, Inc. ("Vanguard"), the
                      Fund and the other funds in the Group obtain at cost
                      virtually all of their corporate management,
                      administrative, shareholder accounting and distribution
                      services. Vanguard also provides investment advisory
                      services on an at-cost basis to certain Vanguard funds. As
                      a result of Vanguard's unique corporate structure, the
                      Vanguard funds have costs substantially lower than those
                      of most competing mutual funds. In 1997, the average
                      expense ratio (annual costs including advisory fees
                      divided by total net assets) for
 
                                       25
<PAGE>   28
 
                      the Vanguard funds amounted to approximately 0.28%
                      compared to an average of 1.24% for the mutual fund
                      industry (data provided by Lipper Analytical Services).
 
                      The Officers of the Fund oversee its day-to-day operations
                      and are responsible to the Fund's Board of Directors. The
                      Directors set broad policies for the Fund and choose its
                      Officers. A list of the Directors and Officers of the Fund
                      and a statement of their present positions and principal
                      occupations during the past five years can be found in the
                      Statement of Additional Information.
 
                      Vanguard employs a supporting staff of management and
                      administrative personnel needed to provide the requisite
                      services to the funds and also furnishes the funds with
                      necessary office space, furnishings and equipment. Each
                      fund pays its share of Vanguard's net expenses, which are
                      allocated among the funds under methods approved by the
                      Board of Directors (Trustees) of each fund. In addition,
                      each fund bears its own direct expenses, such as legal,
                      auditing and custodian fees.
 
                      Vanguard also provides distribution and marketing services
                      to the Vanguard funds. The funds are available on a
                      no-load basis (i.e., there are no sales commissions or
                      12b-1 fees). However, each fund bears its share of the
                      Group's distribution costs.
- --------------------------------------------------------------------------------
 
INVESTMENT
ADVISERS
THE FUND HAS TWO
INVESTMENT ADVISERS   The Fund utilizes two investment advisers. Wellington
                      Management Company, LLP serves as investment adviser to
                      the GNMA and Long-Term Corporate Portfolios; Vanguard's
                      Fixed Income Group serves as investment adviser to the
                      remaining Portfolios.
 
WELLINGTON
MANAGEMENT
COMPANY, LLP          Under an investment advisory agreement with the Fund dated
                      May 1, 1996, Wellington Management Company, LLP ("WMC"),
                      75 State Street, Boston, MA 02109, manages the investment
                      and reinvestment of assets in the GNMA and Long-Term
                      Corporate Portfolios, and continuously reviews, supervises
                      and administers the investment program of these two
                      Portfolios. WMC discharges its responsibilities subject to
                      the control of the Officers and Directors of the Fund.
 
                      WMC is a professional investment counseling firm which
                      globally provides investment services to investment
                      companies, institutions and individuals. Among the clients
                      of WMC are more than 10 of the investment companies of The
                      Vanguard Group. As of January 31, 1998, WMC held
                      discretionary management authority with respect to more
                      than $177 billion of assets. WMC and its predecessor
                      organizations have provided investment advisory services
                      to investment companies since 1928 and to investment
                      counseling clients since 1960.
 
                      Paul D. Kaplan, Senior Vice President of WMC, serves as
                      the portfolio manager for the GNMA Portfolio. Prior to his
                      appointment in 1994, Mr. Kaplan was assistant portfolio
                      manager for the GNMA Portfolio. Mr. Kaplan has been
                      associated with WMC for 20 years and also currently
                      manages the bond components of Vanguard/Wellington Fund
                      and the Balanced Portfolio of the Vanguard Variable
                      Insurance Fund.
 
                                       26
<PAGE>   29
 
                      Earl E. McEvoy, Senior Vice President of WMC, serves as
                      the portfolio manager of the Fund's Long-Term Corporate
                      Portfolio, a position he has held since 1994. Mr. McEvoy
                      also manages the Fund's High Yield Corporate Portfolio as
                      well as Vanguard Preferred Stock Fund, the High Yield Bond
                      Portfolio of the Vanguard Variable Insurance Fund and the
                      bond components of the Utilities Income Portfolio of
                      Vanguard Specialized Portfolios and Vanguard/Wellesley
                      Income Fund. Mr. McEvoy has been associated with WMC for
                      20 years.
 
                      Mr. Kaplan and Mr. McEvoy are supported by research and
                      other investment services provided by the professional
                      staff of WMC.
 
   
                      Under the Fund's investment advisory agreement, the fee
                      paid to WMC is based on the total assets of the GNMA
                      Portfolio and the Long-Term Corporate Portfolio, as well
                      as the total assets of the High Yield Corporate Portfolio
                      of Vanguard Fixed Income Securities Fund, which is offered
                      pursuant to a separate Prospectus. The GNMA and Long-Term
                      Corporate Portfolios pay WMC an aggregate fee at the end
                      of each fiscal quarter, calculated by applying a quarterly
                      rate based on the following annual percentage rates, to
                      the average month-end net assets of each Portfolio for the
                      quarter. Separate fee schedules apply to each Portfolio.
    
 
                                            GNMA PORTFOLIO
 
<TABLE>
<CAPTION>
                                            NET ASSETS               RATE
                               ------------------------------------  -----
                               <S>                                   <C>
                               First $3 billion                      .020%
                               Next $3 billion                       .010%
                               Over $6 billion                       .008%
</TABLE>
 
                                    LONG-TERM CORPORATE PORTFOLIO
 
<TABLE>
<CAPTION>
                                            NET ASSETS               RATE
                               ------------------------------------  -----
                               <S>                                   <C>
                               First $1 billion                      .040%
                               Next $1 billion                       .030%
                               Next $1 billion                       .020%
                               Over $3 billion                       .015%
</TABLE>
 
                      The advisory fee, as determined above, shall be allocated
                      to each Portfolio based on the net assets of each. For the
                      fiscal year ended January 31, 1998, the GNMA and Long-Term
                      Corporate Portfolios paid annual advisory fees to WMC
                      equal to, respectively, .01 of 1%, and .03 of 1% of
                      average net assets.
 
VANGUARD FIXED
INCOME GROUP          The Short-Term U.S. Treasury, Short-Term Federal, Short-
                      and Intermediate-Term Corporate, and Intermediate- and
                      Long-Term U.S. Treasury Portfolios receive all investment
                      advisory services on an at-cost basis from Vanguard's
                      Fixed Income Group. The Group provides investment advisory
                      services to more than 40 Vanguard money market and bond
                      portfolios, both taxable and tax-exempt. Total assets
                      under management by Vanguard's Fixed Income Group were
                      more than $100 billion as of January 31, 1998.
 
                      Ian A. MacKinnon, Managing Director of Vanguard, has been
                      in charge of the Fixed Income Group since its inception in
                      1981. Mr. MacKinnon is responsible for setting
 
                                       27
<PAGE>   30
 
                      the broad investment strategies employed by the Fund, and
                      for overseeing the portfolio managers who implement those
                      strategies on a day-to-day basis. The Fund's portfolio
                      managers are as follows:
 
   
                      - Robert F. Auwaerter, a Principal of Vanguard, serves as
                        portfolio manager of the Long-Term U.S. Treasury,
                        Short-Term Corporate, Intermediate-Term U.S. Treasury,
                        and Intermediate-Term Corporate Portfolios. Associated
                        with the Fixed Income Group since 1981, Mr. Auwaerter
                        has managed the Short-Term Corporate Portfolio since
                        1983, the Long-Term U.S. Treasury Portfolio since 1994,
                        and each of the other two Portfolios since their
                        respective inceptions. (Previously, the Long-Term U.S.
                        Treasury Portfolio was managed by Anthony Jiorle.)
    
 
                      - John Hollyer, a Principal of Vanguard, serves as
                        portfolio manager of the Short-Term U.S. Treasury
                        Portfolio and the Short-Term Federal Portfolio
                        (previously, the Portfolios were managed by Robert
                        Auwaerter). Associated with the Fixed Income Group since
                        1989, Mr. Hollyer began managing the Short-Term Federal
                        Portfolio in 1996 and the Short-Term U.S. Treasury
                        Portfolio in 1998.
 
                      The Fixed Income Group manages the investment and
                      reinvestment of the assets of these six Portfolios and
                      continuously reviews, supervises and administers each
                      Portfolio's investment program, subject to the maturity
                      and quality standards specified in this Prospectus and
                      supplemental guidelines approved by the Fund's Board of
                      Directors. The Fixed Income Group's selection of
                      investments for the Portfolios is based on: (a) continuing
                      credit analysis of those instruments held in the
                      Portfolios and those being considered for inclusion
                      therein; (b) possible disparities in yield relationships
                      between different money market instruments; and (c) actual
                      or anticipated movements in the general level of interest
                      rates.
 
                      Vanguard's Fixed Income Group is also responsible for the
                      placement of portfolio transactions and the negotiation of
                      commissions for the six Portfolios. The purchase and sale
                      of investment securities will ordinarily be principal
                      transactions. Portfolio securities will normally be
                      purchased directly from the issuer or from an underwriter
                      or market maker for the securities. There usually will be
                      no brokerage commissions paid by a Portfolio for
                      securities purchased from an issuer. Purchases from
                      underwriters of securities will include a commission or
                      concession paid by the issuer to the underwriter, and
                      purchases from dealers serving as market makers will
                      include a dealer's mark-up.
 
PORTFOLIO
TRANSACTIONS          The advisers are authorized to choose brokers or dealers
                      to handle the purchase and sale of the Fund's securities,
                      and are directed to get the best available price and most
                      favorable execution from these brokers with respect to all
                      transactions. At times, the advisers may choose brokers
                      who charge higher commissions in the interests of
                      obtaining better execution of a transaction. If more than
                      one broker can obtain the best available price and
                      favorable execution of a transaction, then the advisers
                      are authorized to choose a broker who, in addition to
                      executing the transaction, will provide research services
                      to the advisers or the Fund. However, the advisers will
                      not pay higher commissions specifically for the purpose of
                      obtaining research services. The Fund may direct the
                      advisers to use a particular broker for certain
                      transactions in exchange for commission rebates or
                      research services provided to the Fund.
 
                                       28
<PAGE>   31
 
                      Vanguard's Fixed Income Group may occasionally make
                      recommendations to other Vanguard Funds or clients which
                      result in their purchasing or selling securities
                      simultaneously with a Portfolio of the Fund. As a result,
                      the demand for securities being purchased or the supply of
                      securities being sold may increase, and this could have an
                      adverse effect on the price of those securities. It is the
                      policy of the Fixed Income Group not to favor one client
                      over another in making recommendations or placing an
                      order. If two or more clients are purchasing a given
                      security on the same day from the same broker dealer, such
                      transactions may be averaged as to price.
- --------------------------------------------------------------------------------
 
DIVIDENDS,
CAPITAL GAINS
AND TAXES
DIVIDENDS ARE PAID ON
THE FIRST BUSINESS DAY
OF EACH MONTH         Dividends consisting of virtually all of the ordinary
                      income of each Portfolio of the Fund are declared daily
                      and are payable to shareholders of record at the time of
                      declaration. Such dividends are paid on the first business
                      day of each month. Net capital gains distributions, if
                      any, will be made annually.
 
                      The Fund's dividend and capital gains distributions may be
                      reinvested in additional shares or received in cash. See
                      "Choosing a Distribution Option" for a description of
                      these distribution methods.
 
                      In order to satisfy certain requirements of the Tax Reform
                      Act of 1986, the Fund may declare year-end dividend and
                      capital gains distributions during December. Such
                      distributions, if received by shareholders by January 31,
                      are deemed to have been paid by the Fund and received by
                      shareholders on December 31 of the prior year.
 
                      Each Portfolio of the Fund intends to continue to qualify
                      for taxation as a "regulated investment company" under the
                      Internal Revenue Code so that none of the Portfolios will
                      be subject to federal income tax to the extent its income
                      is distributed to shareholders. Dividends paid by the Fund
                      from net investment income, whether received in cash or
                      reinvested in additional shares, will be taxable to
                      shareholders as ordinary income. For corporate investors,
                      dividends paid by the Fund from net investment income will
                      generally not qualify for the intercorporate
                      dividends-received deduction.
 
   
                      Distributions paid by the Fund from long-term capital
                      gains, whether received in cash or reinvested in
                      additional shares, are taxable as long-term capital gains,
                      regardless of the length of time you have owned shares in
                      the Fund. Long-term capital gains may be taxed at
                      different rates depending on how long a Portfolio held the
                      securities. Capital gains distributions are made when the
                      Fund realizes net capital gains on sales of portfolio
                      securities during the year. For the Fund, realized capital
                      gains are not expected to be a significant or predictable
                      part of investment return.
    
 
                      The Fund will notify you annually as to the tax status of
                      dividend and capital gains distributions paid by the Fund.
                      The Fund is managed without regard to tax ramifications.
 
                                       29
<PAGE>   32
 
A CAPITAL GAIN OR LOSS
MAY BE REALIZED UPON
EXCHANGE OR
REDEMPTION            A sale of shares of the Fund is a taxable event and may
                      result in a capital gain or loss. A capital gain or loss
                      may be realized from an ordinary redemption of shares, a
                      checkwriting redemption, or an exchange of shares between
                      two mutual funds (or two portfolios of a mutual fund).
 
                      Dividend distributions, capital gains distributions, and
                      capital gains or losses from redemptions and exchanges may
                      be subject to state and local taxes. However, depending on
                      provisions of your state's tax law, the portion of a
                      Portfolio's income derived from "full faith and credit"
                      U.S. Treasury obligations may be exempt from state and
                      local taxes. The Fund will indicate each year the portion
                      of a Portfolio's income, if any, that may qualify for this
                      exemption.
 
                      The Fund is required to withhold 31% of taxable dividends,
                      capital gains distributions, and redemptions paid to
                      shareholders who have not complied with IRS taxpayer
                      identification regulations. You may avoid this withholding
                      requirement by certifying on your Account Registration
                      Form your proper Social Security or employer
                      identification number and by certifying that you are not
                      subject to backup withholding.
 
                      The Fund has obtained a Certificate of Authority to do
                      business as a foreign corporation in Pennsylvania and does
                      business and maintains an office in that state. In the
                      opinion of counsel, the shares of the Fund are exempt from
                      Pennsylvania personal property taxes.
 
                      The tax discussion set forth above is included for general
                      information only. Prospective investors should consult
                      their own tax advisers concerning the tax consequences of
                      an investment in the Fund.
- --------------------------------------------------------------------------------
 
THE SHARE PRICE OF
EACH PORTFOLIO        Each Portfolio's share price, or "net asset value" per
                      share, is calculated by dividing the total assets of the
                      Portfolio, less all liabilities, by the total number of
                      shares outstanding, except for the Short-Term Corporate
                      Portfolio whereby net asset value is calculated by
                      dividing the net assets attributed to each share class, by
                      the total number of shares outstanding for that share
                      class. The net asset value is determined as of the close
                      of the New York Stock Exchange (generally 4:00 p.m.
                      Eastern time) on each day that the Exchange is open for
                      trading.
 
                      Short-term instruments (those acquired with remaining
                      maturities of 60 days or less) may be valued at cost, plus
                      or minus any amortized discount or premium, which
                      approximates market value.
 
                      Bonds and other fixed income securities may be valued on
                      the basis of prices provided by a pricing service when
                      such prices are believed to reflect the fair market value
                      of such securities. The prices provided by a pricing
                      service may be determined without regard to bid or last
                      sale prices of each security, but take into account
                      institutional-size transactions in similar groups of
                      securities as well as any developments related to specific
                      securities.
 
                                       30
<PAGE>   33
 
                      Other assets and securities for which no quotations are
                      readily available or which are restricted as to sale (or
                      resale) are valued by such methods as the Board of
                      Directors deems in good faith to reflect fair value.
 
                      The share price for each Portfolio can be found daily in
                      the mutual fund listings of most major newspapers under
                      the heading of Vanguard Funds.
- --------------------------------------------------------------------------------
 
   
GENERAL
INFORMATION           The Fund is a Maryland corporation. The Articles of
                      Incorporation permit the Directors to issue 4,550,000,000
                      shares of common stock, with a $.001 par value. The Board
                      of Directors has the power to designate one or more series
                      ("Portfolios") of shares of common stock and to classify
                      or reclassify any unissued shares with respect to such
                      series. Currently the Fund is offering shares of nine
                      Portfolios.
    
 
                      The shares of each Portfolio are fully paid and
                      non-assessable; have no preference as to conversion,
                      exchange, dividends, retirement or other features; and
                      have no pre-emptive rights. Such shares have
                      non-cumulative voting rights, meaning that the holders of
                      more than 50% of the shares voting for the election of
                      Directors can elect 100% of the Directors if they so
                      choose.
 
                      Annual meetings of shareholders will not be held except as
                      required by the Investment Company Act of 1940 and other
                      applicable law. An annual meeting will be held to vote on
                      the removal of a Director or Directors of the Fund if
                      requested in writing by the holders of not less than 10%
                      of the outstanding shares of the Fund.
 
                      All securities and cash for the GNMA and Long-Term
                      Corporate Portfolios are held by Chase Manhattan Bank, New
                      York, NY. For the Short-Term Federal, Short-Term
                      Corporate, and Long-Term U.S. Treasury Portfolios, all
                      securities and cash are held by CoreStates Bank, N.A.,
                      Philadelphia, PA. For the Short-Term and Intermediate-Term
                      U.S. Treasury and the Intermediate-Term Corporate
                      Portfolios, all securities and cash are held by State
                      Street Bank and Trust Company, Boston, MA. CoreStates
                      Bank, N.A. Philadelphia, PA, holds daily cash balances
                      that are used by the Fund's Portfolios to invest in
                      repurchase agreements or securities acquired in these
                      transactions. The Vanguard Group, Inc., Valley Forge, PA,
                      serves as the Fund's Transfer and Dividend Disbursing
                      Agent. Price Waterhouse LLP serves as independent
                      accountants for the Fund and will audit its financial
                      statements annually. The Fund is not involved in any
                      litigation.
- --------------------------------------------------------------------------------
 
                                       31
<PAGE>   34
 
                               SHAREHOLDER GUIDE
 
OPENING AN
ACCOUNT AND
PURCHASING
SHARES                You may open a regular (non-retirement) account, either by
                      mail or wire. Simply complete and return an Account
                      Registration Form, and any required legal documentation,
                      indicating the Portfolio you have chosen and the amount
                      you wish to invest. Your purchase must be equal to or
                      greater than the $3,000 minimum initial investment
                      requirement for a Portfolio ($1,000 for Individual
                      Retirement Accounts and Uniform Gifts/Transfers to Minors
                      Act accounts, $500 minimum for an Education IRA). You must
                      open a new Individual Retirement Account by mail (IRAs may
                      not be opened by wire) using a Vanguard IRA Adoption
                      Agreement. Your purchase must be equal to or greater than
                      the $1,000 minimum initial investment requirement, but no
                      more than $2,000 if you are making a regular IRA
                      contribution. Rollover contributions are generally limited
                      to the amount withdrawn within the past 60 days from an
                      IRA or other qualified retirement plan. If you need
                      assistance with the forms or have any questions, please
                      call our Investor Information Department (1-800-662-7447).
                      NOTE: For other types of account registrations (e.g.,
                      corporations, associations, other organizations, trusts,
                      or powers of attorney), please call us to determine which
                      additional forms you may need.
 
                      The Fund's shares are purchased at the next-determined net
                      asset value after your investment has been received in the
                      form of Federal Funds. See "When Your Account Will Be
                      Credited." The Fund is offered on a no-load basis (i.e.,
                      there are no sales commissions or 12b-1 fees).
 
PURCHASE
RESTRICTIONS          1) Because of the risks associated with bond investments,
                         the Fund is intended to be a long-term investment
                         vehicle and is not designed to provide investors with a
                         means of speculating on short-term market movements.
                         Consequently, the Fund reserves the right to reject any
                         specific purchase (and exchange purchase) request. The
                         Fund also reserves the right to suspend the offering of
                         shares for a period of time.
 
                      2) Vanguard will not accept third-party checks to purchase
                         shares of the Fund. Please be sure your purchase check
                         is made payable to The Vanguard Group.
 
ADDITIONAL
INVESTMENTS           Subsequent investments to regular accounts may be made by
                      mail ($100 minimum per Portfolio), wire ($1,000 minimum
                      per Portfolio), exchange from another Vanguard Fund
                      account ($100 minimum per Portfolio), or Vanguard Fund
                      Express. Subsequent investments to Individual Retirement
                      Accounts may be made by mail ($100 minimum) or exchange
                      from another Vanguard Fund account. In some instances,
                      contributions may be made by wire or Vanguard Fund
                      Express. Please call us for more information on these
                      options.
- --------------------------------------------------------------------------------
 
                                       32
<PAGE>   35
 
<TABLE>
<S>                             <C>                                         <C>
                                                                            ADDITIONAL INVESTMENTS
                                NEW ACCOUNT                                 TO EXISTING ACCOUNTS
PURCHASING BY MAIL              Please include the amount of                Additional investments should
Complete and sign the           your initial investment and the             include the Invest-by-Mail
enclosed Account                Portfolio(s) you have selected              remittance form attached to your
Registration Form               on the registration form, make              Fund confirmation statements.
                                your check payable to The                   Please make your check payable
                                Vanguard Group -- (Portfolio                to The Vanguard
                                Number) (see below for the                  Group -- (Portfolio Number) (see
                                appropriate Portfolio number),              below for the appropriate
                                and mail to:                                Portfolio number), write your
                                                                            account number on your check
                                THE VANGUARD GROUP                          and, using the return envelope
                                P.O. BOX 2600                               provided, mail to the address
                                VALLEY FORGE, PA 19482-2600                 indicated on the Invest-by-Mail
                                                                            Form.
For express or                  THE VANGUARD GROUP                          All written requests should be
registered mail,                455 DEVON PARK DRIVE                        mailed to one of the addresses
send to:                        WAYNE, PA 19087-1815                        indicated for new accounts. Do
                                                                            not send registered or express
                                                                            mail to the post office box
                                                                            address.
                                VANGUARD FIXED INCOME SECURITIES FUND PORTFOLIO NUMBERS:
                                Short-Term U.S. Treasury -- 32
                                Short-Term Federal -- 49
                                Short-Term Corporate -- 39
                                Intermediate-Term U.S. Treasury -- 35
                                GNMA -- 36
                                Intermediate-Term Corporate -- 71
                                Long-Term U.S. Treasury -- 83
                                Long-Term Corporate -- 28
                                --------------------------------
PURCHASING BY WIRE                                CORESTATES BANK, N.A.
Money should be                                   ABA 031000011
wired to:                                         CORESTATES NO. 0101 9897
                                                  ATTN: VANGUARD
BEFORE WIRING                                     VANGUARD FIXED INCOME SECURITIES FUND
Please contact                                    NAME OF PORTFOLIO
Client Services                                   ACCOUNT NUMBER
(1-800-662-2739)                                  ACCOUNT REGISTRATION
</TABLE>
 
                      To assure proper receipt, please be sure your bank
                      includes the Portfolio name, the account number Vanguard
                      has assigned to you and the eight-digit CoreStates number.
                      If you are opening a new account, you must contact our
                      Client Services Department (1-800-662-2739) before wiring
                      funds. Additionally, complete the
 
                                       33
<PAGE>   36
 
                      Account Registration Form and mail it to the "New Account"
                      address above after completing your wire arrangement.
                      NOTE: Federal Funds wire purchase orders will be accepted
                      only when the Fund and Custodian Bank are open for
                      business.
- --------------------------------------------------------------------------------
PURCHASING BY
EXCHANGE (from a
Vanguard account)     You may open an account or purchase additional shares by
                      making an exchange from an existing Vanguard Fund account.
                      However, the Fund reserves the right to refuse any
                      exchange purchase request. Call our Client Services
                      Department (1-800-662-2739) for assistance. The new
                      account will have the same registration as the existing
                      account.
- --------------------------------------------------------------------------------
PURCHASING BY
FUND EXPRESS
Special Purchase and
Automatic Investment  The Fund Express Special Purchase option lets you move
                      money from your bank account to your Vanguard account on
                      an "as needed" basis. Or, if you choose the Automatic
                      Investment option, money will be moved automatically from
                      your bank account to your Vanguard account on the schedule
                      (monthly, bimonthly [every other month], quarterly,
                      semiannually or annually) you select. To establish these
                      Fund Express options, please provide the appropriate
                      information on the Account Registration Form. We will send
                      you a confirmation of your Fund Express enrollment; please
                      wait two weeks before using the service.
- --------------------------------------------------------------------------------
 
CHOOSING A
DISTRIBUTION
OPTION                You must select one of four distribution options:
 
                      1. AUTOMATIC REINVESTMENT OPTION -- Both dividend and
                         capital gains distributions will be reinvested in
                         additional Portfolio shares. This option will be
                         selected for you automatically unless you specify one
                         of the other options.
 
                      2. CASH DIVIDEND OPTION -- Your dividends will be paid in
                         cash and your capital gains will be reinvested in
                         additional Portfolio shares.
 
                      3. CASH CAPITAL GAINS OPTION -- Your capital gains
                         distributions will be paid in cash and your dividends
                         will be reinvested in additional Portfolio shares.
 
                      4. ALL CASH OPTION -- Both dividend and capital gains
                         distributions will be paid in cash.
 
                      You may change your option by calling our Client Services
                      Department (1-800-662-2739).
 
                      If a shareholder has chosen to receive dividend and/or
                      capital gains distributions in cash, and the postal or
                      other delivery service is unable to deliver checks to the
                      shareholder's address of record, we will change the
                      distribution option so that all dividends and other
                      distributions are automatically reinvested in additional
                      shares. We will not pay interest on uncashed distribution
                      checks.
 
                      In addition, an option to invest your cash dividend and/or
                      capital gains distributions in another Vanguard Fund
                      account is available. Please call our Client Services
                      Department (1-800-662-2739) for information. You may also
                      elect Vanguard Dividend Express which allows you to
                      transfer your cash dividend and/or capital
 
                                       34
<PAGE>   37
 
                      gains distributions automatically to your bank account.
                      Please see "Other Vanguard Services" for more information.
- --------------------------------------------------------------------------------
 
TAX CAUTION
INVESTORS SHOULD ASK
ABOUT THE TIMING OF
CAPITAL GAINS AND
DIVIDEND DISTRIBUTIONS
BEFORE INVESTING      Under Federal tax laws, each Portfolio is required to
                      distribute net capital gains and dividend income to
                      Portfolio shareholders. These distributions are made to
                      all shareholders who own Portfolio shares as of the
                      distribution's record date, regardless of how long the
                      shares have been owned. Purchasing shares just prior to
                      the record date could have significant impact on your tax
                      liability for the year. For example, if you purchase
                      shares immediately prior to the record date of a sizable
                      capital gain, you will be assessed taxes on the amount of
                      the capital gains distribution even though you owned the
                      Portfolio shares for just a short period of time. (Taxes
                      are due on the distributions even if the dividend or
                      capital gain is reinvested in additional Portfolio
                      shares.) While the total value of your investment will be
                      the same after the capital gains distribution -- the
                      amount of the capital gains distribution will offset the
                      drop in the net asset value of the shares -- you should be
                      aware of the tax implications the timing of your purchase
                      may have.
 
                      Prospective investors should, therefore, inquire about
                      potential distributions before investing. Each Portfolio
                      of the Fund normally distributes capital gains in
                      December, while income dividends are generally paid on the
                      first business day of each month. In addition, each
                      Portfolio may occasionally be required to make
                      supplemental dividend or capital gains distributions at
                      some other time during the year. For additional
                      information on distributions and taxes, see the section
                      titled "Dividends, Capital Gains and Taxes."
- --------------------------------------------------------------------------------
 
IMPORTANT
INFORMATION
ESTABLISHING
OPTIONAL SERVICES     The easiest way to establish optional Vanguard services on
                      your account is to select the options you desire when you
                      complete your Account Registration Form.
 
                      IF YOU WISH TO ADD OPTIONS LATER, YOU MAY NEED TO PROVIDE
                      VANGUARD WITH ADDITIONAL INFORMATION AND A SIGNATURE
                      GUARANTEE. PLEASE CALL OUR CLIENT SERVICES DEPARTMENT
                      (1-800-662-2739) FOR FURTHER ASSISTANCE.
 
SIGNATURE GUARANTEES  For our mutual protection, we may require a signature
                      guarantee on certain written transaction requests. A
                      signature guarantee verifies the authenticity of your
                      signature and may be obtained from banks, brokers and any
                      other guarantor that Vanguard deems acceptable. A
                      SIGNATURE GUARANTEE CANNOT BE PROVIDED BY A NOTARY PUBLIC.
 
CERTIFICATES          Share certificates will be issued upon request for all
                      Portfolios except the Short- and Intermediate-Term U.S.
                      Treasury and Intermediate-Term Corporate Portfolios. If a
                      certificate is lost, you may incur an expense to replace
                      it.
 
BROKER/DEALER
PURCHASES             If you purchase shares in Vanguard Funds through a
                      registered broker/dealer or investment adviser, the
                      broker/dealer or adviser may charge a service fee.
 
CANCELLING TRADES     The Fund will not cancel any trade (e.g., a purchase,
                      exchange or redemption) believed to be authentic, once the
                      trade request has been received in writing or by
                      telephone.
 
                                       35
<PAGE>   38
 
ELECTRONIC PROSPECTUS
DELIVERY              You may receive a prospectus for the Fund or any of the
                      Vanguard Funds in an electronic format through Vanguard's
                      website at www.vanguard.com. For additional information
                      please see "Other Vanguard Services -- Computer Access."
- --------------------------------------------------------------------------------
 
WHEN YOUR
ACCOUNT WILL
BE CREDITED           The trade date is the date on which your account is
                      credited. It is generally the day on which the Fund
                      receives your investment in the form of Federal Funds
                      (monies credited to the Fund's Custodian Bank by a Federal
                      Reserve Bank).
 
                      Purchases by check will receive a trade date the day the
                      funds are received in good order by Vanguard. Thus, if
                      your purchase by check is received by the close of trading
                      on the New York Stock Exchange (the "Exchange"), generally
                      4:00 p.m. Eastern time, your trade date is the business
                      day your check is received in good order. If your purchase
                      is received after the close of trading on the Exchange,
                      your trade date is the business day following receipt of
                      your check. You will begin to earn dividends on the
                      calendar day following the trade date. (For a Friday trade
                      date, you will begin earning dividends on Saturday.)
 
                      For purchases by Federal Funds wire or exchange, the Fund
                      is credited immediately with Federal Funds. Thus, if your
                      purchase by Federal Funds wire or exchange is received by
                      the close of trading on the Exchange, your trade date is
                      the day of receipt. If your purchase is received after the
                      close of trading on the Exchange, your trade date is the
                      business day following receipt of your wire or exchange.
 
                      In order to prevent lengthy processing delays caused by
                      the clearing of foreign checks, Vanguard will only accept
                      a foreign check which has been drawn in U.S. dollars and
                      has been issued by a foreign bank with a U.S.
                      correspondent bank. The name of the U.S. correspondent
                      bank must be printed on the face of the foreign check.
- --------------------------------------------------------------------------------
 
SELLING YOUR
SHARES                You may withdraw any portion of the funds in your account
                      by redeeming shares at any time. (Please see "Important
                      Redemption Information.") You generally may initiate a
                      request by writing or by telephoning. Your redemption
                      proceeds are normally mailed, credited or
                      wired -- depending upon the method of withdrawal you have
                      previously chosen -- within two business days after the
                      receipt of the request in Good Order. No interest will
                      accrue on amounts represented by uncashed redemption
                      checks.
 
SELLING BY WRITING
A CHECK               You may withdraw funds from your account by writing a
                      check payable in the amount of $250 or more. When a check
                      is presented for payment to the Fund's agent, CoreStates
                      Bank, N.A., the Fund will redeem sufficient shares in your
                      account at the next determined net asset value to cover
                      the amount of the check. You cannot write a Vanguard check
                      to redeem shares that you purchased by check within the
                      previous ten calendar days.
 
                      In order to establish the checkwriting option on your
                      account, all registered shareholders must sign a signature
                      card. After your completed signature card is received by
                      the Fund, an initial supply of checks will be mailed
                      within 10 business days. There is no charge for checks or
                      for their clearance. CORPORATIONS, TRUSTS
 
                                       36
<PAGE>   39
 
                      AND OTHER ORGANIZATIONS SHOULD CALL OUR CLIENT SERVICES
                      DEPARTMENT (1-800-662-2739) BEFORE SUBMITTING SIGNATURE
                      CARDS, AS ADDITIONAL DOCUMENTS MAY BE REQUIRED TO
                      ESTABLISH THE CHECKWRITING SERVICE.
 
                      Before establishing the checkwriting option, you should be
                      aware that:
 
                      1. Writing a check (a redemption of shares) is a taxable
                         event.
 
                      2. The Fund does not allow an account to be closed through
                         the checkwriting option.
 
                      3. Vanguard cannot guarantee a stop payment on any check.
                         If you wish to reverse a stop payment order, you must
                         do so in writing.
 
                      4. Shares held in certificate form cannot be redeemed
                         using the checkwriting option.
 
                      5. The Fund reserves the right to terminate or alter this
                         service at any time.
- --------------------------------------------------------------------------------
SELLING BY MAIL       Requests should be mailed to THE VANGUARD GROUP, VANGUARD
                      FIXED INCOME SECURITIES FUND, P.O. BOX 1120, VALLEY FORGE,
                      PA 19482-1120. (For express or registered mail, send your
                      request to The Vanguard Group, Vanguard Fixed Income
                      Securities Fund, 455 Devon Park Drive, Wayne, PA
                      19087-1815.)
 
                      The redemption price of shares will be the Portfolio's net
                      asset value next determined after Vanguard has received
                      all required documents in Good Order.
- --------------------------------------------------------------------------------
DEFINITION OF GOOD
ORDER                 GOOD ORDER means that the request includes the following:
 
                      1. The account number and Portfolio name.
                      2. The amount of the transaction (specified in dollars or
                         shares).
                      3. The signatures of all owners EXACTLY as they are
                         registered on the account.
                      4. Any required signature guarantees.
                      5. Any other supporting legal documentation that may be
                         required in the case of estates, corporations, trusts
                         and certain other accounts.
                      6. Any certificates that you hold for the account.
 
                      IF YOU HAVE QUESTIONS ABOUT THIS DEFINITION AS IT PERTAINS
                      TO YOUR REQUEST, PLEASE CALL OUR CLIENT SERVICES
                      DEPARTMENT (1-800-662-2739).
- --------------------------------------------------------------------------------
SELLING BY
TELEPHONE             To sell shares by telephone, you or your pre-authorized
                      representative may call our Client Services Department at
                      1-800-662-2739. For telephone redemptions, you may have
                      the proceeds sent to you by mail or by wire. In addition
                      to the details below, please see "Important Information
                      About Telephone Transactions."
 
                      BY MAIL: Telephone mail redemption is automatically
                      established on your account unless you indicate otherwise
                      on your Account Registration Form. You may redeem any
                      amount by calling Vanguard. The proceeds will be paid to
                      the registered shareholders and mailed to the address of
                      record. PLEASE NOTE: As a protection against fraud, your
                      telephone mail redemption privilege will be suspended for
                      15 calendar days following any expedited address change to
                      your account. An expedited address change is one that is
                      made by telephone or in writing, without the signatures of
                      all account owners.
 
                                       37
<PAGE>   40
 
                      BY WIRE: Telephone wire redemption must be specifically
                      elected for your account. The best time to elect telephone
                      wire redemption is at the time you complete your Account
                      Registration Form. If you do not presently have telephone
                      wire redemption and wish to establish it, please contact
                      our Client Services Department.
 
                      With the wire redemption option, you may withdraw a
                      minimum of $1,000 and have the amount wired directly to
                      your bank account. Wire redemptions less than $5,000 are
                      subject to a $5 charge deducted by Vanguard. There is no
                      Vanguard charge for wire redemptions of $5,000 or more.
                      However, your bank may assess a separate fee to accept
                      incoming wires.
 
                      A request to change the bank associated with your wire
                      redemption option must be received in writing, signed by
                      each registered shareholder, and accompanied by a voided
                      check or preprinted deposit slip. A signature guarantee is
                      required if your bank registration is not identical to
                      your Vanguard Fund account registration.
- --------------------------------------------------------------------------------
SELLING BY FUND
EXPRESS
Automatic Withdrawal
& Special Redemption  If you select the Fund Express Automatic Withdrawal
                      option, money will be automatically moved from your
                      Vanguard Fund account to your bank account according to
                      the schedule you have selected. The Special Redemption
                      option lets you move money from your Vanguard account to
                      your bank account on an "as needed" basis. To establish
                      these Fund Express options, please provide the appropriate
                      information on the Account Registration Form. We will send
                      you a confirmation on your Fund Express service; please
                      wait two weeks before using the service.
- --------------------------------------------------------------------------------
SELLING BY EXCHANGE   You may sell shares of the Fund by making an exchange into
                      another Vanguard Fund account. Please see "Exchanging Your
                      Shares" for details.
- --------------------------------------------------------------------------------
IMPORTANT
REDEMPTION
INFORMATION           Shares purchased by check or Fund Express may be redeemed
                      at any time. However, your redemption proceeds will not be
                      paid until payment for the purchase is collected, which
                      may take up to ten calendar days.
- --------------------------------------------------------------------------------
DELIVERY OF
REDEMPTION PROCEEDS   Redemption requests received by telephone prior to the
                      close of the Exchange are processed on the day of receipt
                      and the redemption proceeds are normally sent on the
                      following business day.
 
                      Redemption requests received by telephone after the close
                      of the Exchange are processed on the business day
                      following receipt and the proceeds are normally sent on
                      the second business day following receipt.
 
                      Redemption proceeds must be sent to you within seven days
                      of receipt of your request in Good Order, except as
                      described above in "Important Redemption Information."
 
                      If you experience difficulty in making a telephone
                      redemption during periods of drastic economic or market
                      changes, your redemption request may be made by regular or
                      express mail. It will be implemented at the net asset
                      value next determined after your request has been received
                      by Vanguard in Good Order. The Fund reserves the right to
                      revise or terminate the telephone redemption privilege at
                      any time.
 
                                       38
<PAGE>   41
 
                      The Fund may suspend the redemption right or postpone
                      payment at times when the New York Stock Exchange is
                      closed or under any emergency circumstances as determined
                      by the United States Securities and Exchange Commission.
 
                      If the Board of Directors determines that it would be
                      detrimental to the best interests of the Fund's remaining
                      shareholders to make payment in cash, the Fund may pay
                      redemption proceeds of amounts in excess of $250,000 in
                      whole or in part by a distribution in kind of readily
                      marketable securities.
- --------------------------------------------------------------------------------
VANGUARD'S AVERAGE
COST STATEMENT        If you make a redemption from a qualifying account,
                      Vanguard will send you an Average Cost Statement which
                      provides you with the tax basis of the shares you
                      redeemed. Please see "Statements and Reports" for
                      additional information.
- --------------------------------------------------------------------------------
LOW BALANCE FEE AND
MINIMUM ACCOUNT
BALANCE REQUIREMENT   Due to the relatively high cost of maintaining smaller
                      accounts, each Portfolio will automatically deduct a $10
                      annual fee in either June or December from non-retirement
                      accounts with balances falling below $2,500 ($500 for
                      Uniform Gifts/Transfers to Minors Act accounts). The fee
                      generally will be waived for investors whose aggregate
                      Vanguard assets exceed $50,000.
 
                      In addition, each Portfolio reserves the right to
                      liquidate any non-retirement account that is below the
                      minimum initial investment amount of $3,000. If at any
                      time your total investment does not have a value of at
                      least $3,000, you may be notified that your account is
                      below the Fund's minimum account balance requirement. You
                      would then be allowed 60 days to make an additional
                      investment before the account is liquidated. Proceeds
                      would be promptly paid to the registered shareholder.
 
                      Vanguard will not liquidate your account if it has fallen
                      below $3,000 solely as a result of declining markets
                      (i.e., a decline in a Portfolio's net asset value).
- --------------------------------------------------------------------------------
 
EXCHANGING YOUR
SHARES
EXCHANGING BY
TELEPHONE
Call Client Services
(1-800-662-2739)      Should your investment goals change, you may exchange your
                      shares of Vanguard Fixed Income Securities Fund for those
                      of other available Vanguard Funds.
 
                      When exchanging shares by telephone, please have ready the
                      Portfolio name, account number, Social Security number or
                      employer identification number listed on the account, and
                      exact name and address in which the account is registered.
                      Only the registered shareholder may complete such an
                      exchange. Requests for telephone exchanges received prior
                      to the close of trading on the Exchange are processed at
                      the close of business that same day. Requests received
                      after the close of the Exchange are processed the next
                      business day. TELEPHONE EXCHANGES ARE NOT ACCEPTED INTO OR
                      FROM NON-RETIREMENT INVESTMENTS IN VANGUARD INDEX TRUST,
                      VANGUARD BALANCED INDEX FUND, VANGUARD INTERNATIONAL
                      EQUITY INDEX FUND, VANGUARD REIT INDEX PORTFOLIO, VANGUARD
                      TOTAL INTERNATIONAL PORTFOLIO, and VANGUARD GROWTH AND
                      INCOME PORTFOLIO. If you experience difficulty in making a
                      telephone exchange, your exchange request may be made by
                      regular or express mail, and it will be implemented at the
                      closing net asset value on the date received by Vanguard,
                      provided the request is received in Good Order.
- --------------------------------------------------------------------------------
 
                                       39
<PAGE>   42
 
EXCHANGING BY MAIL    Please be sure to include on your exchange request the
                      name and account number of your current Portfolio, the
                      name of the Fund you wish to exchange into, the amount you
                      wish to exchange, and the signatures of all registered
                      account holders. Send your request to THE VANGUARD GROUP,
                      VANGUARD FIXED INCOME SECURITIES FUND, P.O. BOX 1120,
                      VALLEY FORGE, PA 19482-1120. (For express or registered
                      mail, send your request to The Vanguard Group, Vanguard
                      Fixed Income Securities Fund, 455 Devon Park Drive, Wayne,
                      PA 19087-1815.)
- --------------------------------------------------------------------------------
EXCHANGING ONLINE     You may use your personal computer to exchange shares of
                      most Vanguard funds by accessing our website
                      (www.vanguard.com). To establish this service for your
                      account, you must first register through the website. We
                      will then send to you, by mail, an account access password
                      that will enable you to make online exchanges.
 
                      The Vanguard funds that you cannot purchase or sell
                      through online exchange are VANGUARD INDEX TRUST, VANGUARD
                      BALANCED INDEX FUND, VANGUARD INTERNATIONAL EQUITY INDEX
                      FUND, VANGUARD REIT INDEX PORTFOLIO, VANGUARD TOTAL
                      INTERNATIONAL PORTFOLIO, and VANGUARD GROWTH AND INCOME
                      PORTFOLIO (formerly known as Vanguard Quantitative
                      Portfolios). These funds do permit online exchanges within
                      IRAs and other retirement accounts.
- --------------------------------------------------------------------------------
 
IMPORTANT EXCHANGE
INFORMATION           Before you make an exchange, you should consider the
                      following:
 
                      - Please read the Fund's prospectus before making an
                        exchange. For a copy and for answers to any questions
                        you may have, call our Investor Information Department
                        (1-800-662-7447).
 
                      - An exchange is treated as a redemption and a purchase.
                        Therefore, you could realize a taxable gain or loss on
                        the transaction.
 
                      - Exchanges by telephone are accepted only if the
                        registrations and the taxpayer identification numbers of
                        the two accounts are identical.
 
                      - To exchange into an account with a different
                        registration (including a different name, address, or
                        taxpayer identification number), you must provide
                        Vanguard with written instructions that include the
                        guaranteed signatures of all current account owners.
 
   
                      - New accounts are not currently accepted in
                        Vanguard/Windsor Fund, Vanguard/PRIMECAP Fund or
                        Vanguard Trustees' Equity Fund -- U.S. Portfolio.
    
 
                      - The redemption price of shares redeemed by exchange is
                        the net asset value next determined after Vanguard has
                        received all required documentation in Good Order.
 
                      - When opening a new account by exchange, you must meet
                        the minimum investment requirement of the new Fund.
 
                                       40
<PAGE>   43
 
                      Every effort will be made to maintain the exchange
                      privilege. However, the Fund reserves the right to revise
                      or terminate its provisions, limit the amount of, or
                      reject any exchange, as deemed necessary, at any time.
- --------------------------------------------------------------------------------
 
EXCHANGE
PRIVILEGE
LIMITATIONS           The Fund's exchange privilege is not intended to afford
                      shareholders a way to speculate on short-term movements in
                      the market. Accordingly, in order to prevent excessive use
                      of the exchange privilege that may potentially disrupt the
                      management of the Fund and increase transaction costs, the
                      Fund has established a policy of limiting excessive
                      exchange activity.
 
                      Exchange activity will not be deemed excessive if limited
                      to TWO SUBSTANTIVE EXCHANGE REDEMPTIONS (AT LEAST 30 DAYS
                      APART) from a Portfolio during any twelve-month period.
                      "Substantive" means either a dollar amount or a series of
                      movements between Vanguard Funds that Vanguard determines,
                      in its sole discretion, could have an adverse impact on
                      the management of the Fund. Notwithstanding these
                      limitations, the Fund reserves the right to reject any
                      purchase request (including exchange purchases from other
                      Vanguard portfolios) that is reasonably deemed to be
                      disruptive to efficient portfolio management.
- --------------------------------------------------------------------------------
 
IMPORTANT
INFORMATION
ABOUT TELEPHONE
TRANSACTIONS          The ability to initiate redemptions (except wire or Fund
                      Express redemptions) and exchanges by telephone is
                      automatically established on your account unless you
                      request in writing that telephone transactions on your
                      account not be permitted. The ability to initiate wire
                      redemptions by telephone will be established on your
                      account only if you specifically elect this option in
                      writing.
 
                      To protect your account from losses resulting from
                      unauthorized or fraudulent telephone instructions,
                      Vanguard adheres to the following security procedures:
 
                      1. SECURITY CHECK.  To request a transaction by telephone,
                         the caller must know (i) the name of the Portfolio;
                         (ii) the 10-digit account number; (iii) the exact name
                         and address used in the registration; and (iv) the
                         Social Security or employer identification number
                         listed on the account.
 
                      2. PAYMENT POLICY.  The proceeds of any telephone
                         redemption by mail will be made payable to the
                         registered shareowner and mailed to the address of
                         record only. In the case of a telephone redemption by
                         wire, the wire transfer will be made only in accordance
                         with the shareowner's prior written instructions.
 
                      Neither the Fund nor Vanguard will be responsible for the
                      authenticity of transaction instructions received by
                      telephone, provided that reasonable security procedures
                      have been followed. Vanguard believes that the security
                      procedures described above are reasonable, and that if
                      such procedures are followed, you will bear the risk of
                      any losses resulting from unauthorized or fraudulent
                      telephone transactions on your account.
- --------------------------------------------------------------------------------
 
TRANSFERRING
REGISTRATION          You may transfer the registration of any of your Fund
                      shares to another person by completing a transfer form and
                      sending it to: THE VANGUARD GROUP, ATTENTION: TRANSFER
                      DEPARTMENT, P.O. BOX 1110, VALLEY FORGE, PA 19482-1110.
                      The request
 
                                       41
<PAGE>   44
 
                      must be in Good Order. To receive a transfer form and full
                      instructions, please call our Client Services Department
                      (1-800-662-2739).
- --------------------------------------------------------------------------------
 
STATEMENTS AND
REPORTS               Vanguard will send you a confirmation statement each time
                      you initiate a transaction in your account except for
                      checkwriting redemptions from Vanguard money market
                      accounts. You will also receive a comprehensive account
                      statement at the end of each calendar quarter. The
                      fourth-quarter statement will be a year-end statement,
                      listing all transaction activity for the entire calendar
                      year.
 
                      Vanguard's Average Cost Statement provides you with the
                      average cost of shares redeemed from your account during
                      the calendar year, using the average cost single category
                      method. This service is available for most taxable
                      accounts opened since January 1, 1986. In general,
                      investors who redeemed shares from a qualifying Vanguard
                      account may expect to receive their Average Cost Statement
                      along with their Portfolio Summary Statement. Please call
                      our Client Services Department (1-800-662-2739) for
                      information.
 
                      A checkwriting statement will be sent monthly to
                      shareholders using Vanguard's checkwriting option. Our
                      clear, easy-to-use statement provides images of the front
                      and back of each checkwriting draft paid in the previous
                      month. This consolidated statement is sent instead of the
                      original canceled drafts, which will not be returned.
 
                      Financial reports on the Fund will be mailed to you
                      semiannually, according to the Fund's fiscal year-end. To
                      keep the Fund's costs as low as possible (so that you and
                      other shareholders can keep more of the Fund's investment
                      earnings), Vanguard attempts to eliminate duplicate
                      mailings to the same address. When we find that two or
                      more Fund shareholders have the same last name and
                      address, we send just one Fund report to that
                      address -- instead of mailing separate reports to each
                      shareholder. If you want us to send separate reports,
                      however, you may notify our Investor Information
                      Department at 1-800-662-7447.
- --------------------------------------------------------------------------------
OTHER VANGUARD
SERVICES              For more information about any of these services, please
                      call our Investor Information Department at
                      1-800-662-7447.
 
VANGUARD DIRECT
DEPOSIT SERVICE       With Vanguard's Direct Deposit Service, most U.S.
                      Government checks (including Social Security and military
                      pension checks) and private payroll checks may be
                      automatically deposited into your Vanguard Fund account.
                      Separate brochures and forms are available for direct
                      deposit of U.S. Government and private payroll checks.
 
VANGUARD AUTOMATIC
EXCHANGE SERVICE      Vanguard's Automatic Exchange Service allows you to move
                      money automatically among your Vanguard Fund accounts. For
                      instance, the service can be used to "dollar cost average"
                      from a money market portfolio into a stock or bond fund or
                      to contribute to an IRA or other retirement plan. Please
                      contact our Client Services Department at 1-800-662-2739
                      for additional information.
 
VANGUARD FUND
EXPRESS               Vanguard's Fund Express allows you to transfer money
                      between your Fund account and your account at a bank,
                      savings and loan association, or a credit union that is a
                      member of the Automated Clearing House (ACH) system. You
                      may elect this service
 
                                       42
<PAGE>   45
 
                      on the Account Registration Form or call our Investor
                      Information Department (1-800-662-7447) for a Fund Express
                      application.
 
                      Special rules govern how your Fund Express purchases or
                      redemptions are credited to your account. In addition,
                      some services of Fund Express cannot be used with specific
                      Vanguard Funds. For more information, please refer to the
                      Vanguard Fund Express brochure.
 
VANGUARD DIVIDEND
EXPRESS               Vanguard's Dividend Express allows you to transfer your
                      dividend and/or capital gains distributions automatically
                      from your Fund account, one business day after the Fund's
                      payable date, to your account at a bank, savings and loan
                      association, or a credit union that is a member of the
                      Automated Clearing House (ACH) system. You may elect this
                      service on the Account Registration Form or call the
                      Investor Information Department (1-800-662-7447) for a
                      Vanguard Dividend Express application.
 
VANGUARD
TELE-ACCOUNT(R)       Vanguard's Tele-Account is a convenient, automated service
                      that provides share price, price change and yield
                      quotations on Vanguard Funds through any TouchTone(TM)
                      telephone. This service also lets you obtain information
                      about your account balance, your last transaction, and
                      your most recent dividend or capital gains payment. In
                      addition, you may perform investment exchanges of Vanguard
                      Fund shares and redemptions by check using Tele-Account.
                      To contact Vanguard's Tele-Account service, dial
                      1-800-ON-BOARD (1-800-662-6273). A brochure offering
                      detailed operating instructions is available from our
                      Investor Information Department (1-800-662-7447).
 
COMPUTER ACCESS
 
VANGUARD ONLINE
www.vanguard.com      Use your personal computer to learn more about Vanguard's
                      funds and services; keep in touch with your Vanguard
                      accounts; map out a long-term investment strategy;
                      initiate certain transactions; and ask questions, make
                      suggestions, and send messages to Vanguard.
 
                      Our education-oriented website provides timely news and
                      information about Vanguard's funds and services; an online
                      "university" that offers a variety of mutual fund classes;
                      and easy-to-use, interactive tools to help you create your
                      own investment and retirement strategies.
- --------------------------------------------------------------------------------
 
                                       43
<PAGE>   46
 
- --------------------------------------------------------------------------------
 
<TABLE>
<S>                             <C>                                   <C>
 
                                                                                                             [FLAG LOGO]
                                [VANGUARD FIXED INCOME SECURITIES                     [VANGUARD FIXED INCOME SECURITIES FUND LOGO]
                                FUND LOGO]                                                   P   R   O   S   P   E   C   T   U   S
                                ---------------------------
                                                                                                                      MAY 29, 1998
                                THE VANGUARD GROUP
                                P.O. Box 2600                                                            [THE VANGUARD GROUP LOGO]
                                Valley Forge, PA 19482
                                INVESTOR INFORMATION
                                DEPARTMENT:
                                1-800-662-7447 (SHIP)
                                CLIENT SERVICES
                                DEPARTMENT:
                                1-800-662-2739 (CREW)
                                TELE-ACCOUNT FOR
                                24-HOUR ACCESS:
                                1-800-662-6273 (ON-BOARD)
                                TELECOMMUNICATION SERVICE
                                FOR THE HEARING-IMPAIRED:
                                1-800-662-2738
                                TRANSFER AGENT:
                                The Vanguard Group, Inc.
                                P.O. Box 2600
                                Valley Forge, PA 19482

      P028

</TABLE>
 
- --------------------------------------------------------------------------------
<PAGE>   47
 
================================================================================
 
[Vanguard Logo]                                   A Member of The Vanguard Group
================================================================================
 
PROSPECTUS -- MAY 29, 1998
- --------------------------------------------------------------------------------
 
FUND INFORMATION: PARTICIPANT SERVICES -- 1-800-523-1188; INSTITUTIONAL INVESTOR
SERVICES -- 1-800-523-1036
- --------------------------------------------------------------------------------
 
INVESTMENT
OBJECTIVES
AND POLICIES          Vanguard Fixed Income Securities Fund, Inc. (the "Fund")
                      is an open-end diversified investment company that seeks
                      to provide investors with a high level of current income
                      consistent with the maintenance of principal and
                      liquidity. The Fund consists of nine distinct Portfolios,
                      each of which invests in fixed income securities within
                      prescribed maturity and credit quality standards. A
                      majority of the assets of the High Yield Corporate
                      Portfolio may be rated Ba or B. Securities with such
                      ratings are commonly referred to as "junk bonds" and are
                      considered speculative by the major ratings agencies.
                      Purchasers should carefully assess the risks associated
                      with an investment in this Portfolio. There is no
                      assurance that any of the Fund's Portfolios will achieve
                      its stated objective. Shares of the Fund are neither
                      insured nor guaranteed by any agency of the U.S.
                      Government, including the FDIC.
- --------------------------------------------------------------------------------
 
IMPORTANT NOTE        This Prospectus is intended exclusively for participants
                      in employer-sponsored retirement or savings plans, such as
                      tax-qualified pension or profit-sharing plans and 401(k)
                      thrift plans, as well as 403(b) custodial accounts for
                      non-profit educational and charitable organizations.
                      Another version of this Prospectus, containing information
                      on how to open a personal investment account with the
                      Fund, is available for individual investors. To obtain a
                      copy of that version of the Prospectus, please call
                      1-800-662-7447.
- --------------------------------------------------------------------------------
 
   
OPENING AN
ACCOUNT               One or more of the Portfolios of the Fund is an investment
                      option under a retirement or savings program sponsored by
                      your employer. The administrator of your retirement plan
                      or your employee benefits office can provide you with
                      detailed information on how to participate in your plan
                      and how to elect a Portfolio as an investment option. If
                      you have any questions about the Fund, please contact
                      Participant Services (1-800-523-1188). If you have any
                      questions about your plan account, contact your plan
                      administrator or the organization that provides
                      recordkeeping services for your plan.
    
- --------------------------------------------------------------------------------
 
ABOUT THIS
PROSPECTUS            This Prospectus is designed to set forth concisely the
                      information you should know about the Fund before you
                      invest. It should be retained for future reference. A
                      "Statement of Additional Information" containing
                      additional information about the Fund has been filed with
                      the Securities and Exchange Commission. This Statement is
                      dated May 29, 1998 and has been incorporated by reference
                      into this Prospectus. A copy may be obtained without
                      charge by writing to the Fund, calling Participant
                      Services at 1-800-523-1188, or visiting the Securities and
                      Exchange Commission's website (www.sec.gov).
- --------------------------------------------------------------------------------
 
TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                  Page
<S>                               <C>
 Highlights......................   2
 Fund Expenses...................   5
 Financial Highlights............   6
 Yield and Total Return..........  11
 Investment Objective............  12
 Investment Policies.............  12
</TABLE>
 
<TABLE>
<CAPTION>
                                  Page
<S>                               <C>
 Investment Risks................  18
 Who Should Invest...............  22
 Implementation of Policies......  23
 Investment Limitations..........  28
 Management of the Fund..........  28
 Investment Advisers.............  29
</TABLE>
 
<TABLE>
<CAPTION>
                                  Page
<S>                               <C>
 Dividends, Capital Gains and
   Taxes.........................  32
 The Share Price of Each
 Portfolio.......................  32
 General Information.............  33
 Service Guide...................  34
</TABLE>
 
- --------------------------------------------------------------------------------
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION, NOR HAS THE SECURITIES AND EXCHANGE COMMISSION PASSED UPON
THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY
IS A CRIMINAL OFFENSE.
- --------------------------------------------------------------------------------
 
- --------------------------------------------------------------------------------
<PAGE>   48
 
                                   HIGHLIGHTS
 
OBJECTIVE AND
POLICIES              The Fund is a no-load, open-end diversified investment
                      company that seeks to provide investors with a high level
                      of income consistent with the maintenance of principal and
                      liquidity. The Fund consists of nine distinct Portfolios,
                      each of which invests in fixed income securities within
                      prescribed maturity and quality standards. There is no
                      assurance that the Fund will achieve its stated objective.
                                                                         PAGE 12
- --------------------------------------------------------------------------------
 
NINE SEPARATE
PORTFOLIOS            The investment characteristics of each Portfolio are
                      summarized in the chart below. As illustrated, the Fund
                      consists of three short-term Portfolios, three
                      intermediate-term Portfolios, two long-term Portfolios,
                      and a high-risk Portfolio investing in low-quality
                      bonds.                                             PAGE 12
 
   
<TABLE>
<CAPTION>
 
                            PORTFOLIO SUMMARY
- -------------------------------------------------------------------------
                                         PRIMARY            EXPECTED
  PORTFOLIO                            INVESTMENTS      AVERAGE MATURITY
<S>                                <C>                  <C>
- -------------------------------------------------------------------------
  Short-Term U.S. Treasury         U.S. Treasury bonds      1-3 years
  Short-Term Federal                 U.S. Government        1-3 years
                                      agency bonds
  Short-Term Corporate*             Investment grade        1-3 years
                                     corporate bonds
- -------------------------------------------------------------------------
  Intermediate-Term U.S. Treasury  U.S. Treasury bonds     5-10 years
  GNMA                                GNMA mortgage      Intermediate**
                                      certificates
  Intermediate-Term Corporate       Investment grade       5-10 years
                                     corporate bonds
- -------------------------------------------------------------------------
  Long-Term U.S. Treasury          U.S. Treasury bonds     15-30 years
  Long-Term Corporate               Investment grade       15-25 years
                                     corporate bonds
- -------------------------------------------------------------------------
  High Yield Corporate              Speculative grade    Intermediate**
                                     corporate bonds
- -------------------------------------------------------------------------
</TABLE>
    
 
 * This Prospectus offers Short-Term Corporate Portfolio's Investor Shares.
 
** While neither the GNMA nor the High Yield Corporate Portfolios observe
   specific maturity guidelines, each is expected to maintain an
   intermediate-term average weighted maturity.
- --------------------------------------------------------------------------------
 
RISK
CHARACTERISTICS       Investors in the Fund are exposed to four types of risk
                      from fixed income securities. (1) INTEREST RATE RISK is
                      the potential for fluctuations in bond prices due to
                      changing interest rates. (2) INCOME RISK is the potential
                      for a decline in a Portfolio's income due to falling
                      market interest rates. (3) CREDIT RISK is the possibility
                      that a bond issuer will fail to make timely payments of
                      either interest or principal to a Portfolio. (4)
                      PREPAYMENT RISK (for mortgage-backed securities) or CALL
                      RISK (for corporate bonds) is the likelihood that, during
                      periods of falling interest rates, securities with
 
                                        2
<PAGE>   49
 
                      high stated interest rates will be prepaid (or "called")
                      prior to maturity, requiring a Portfolio to invest the
                      proceeds at generally lower interest rates.
 
                      The following chart summarizes interest rate, credit,
                      income and prepayment/call risks for each of the nine
                      Portfolios of the Fund. As shown, interest rate risk
                      should be low for the three short-term Portfolios,
                      moderate for the three intermediate-term Portfolios and
                      the High Yield Corporate Portfolio, and high for the two
                      long-term Portfolios. The High Yield Corporate Portfolio
                      is unique among the Fund's Portfolios in its substantial
                      exposure to credit risk.                           PAGE 18
 
<TABLE>
<CAPTION>
 
                                                           RISK SUMMARY
                            ---------------------------------------------------------------------------
                                                           INTEREST    INCOME     CREDIT    PREPAYMENT/
                              PORTFOLIO                    RATE RISK    RISK       RISK      CALL RISK
                            ---------------------------------------------------------------------------
                            <S>                            <C>         <C>      <C>         <C>
                              Short-Term U.S. Treasury       Low       High     Negligible  Negligible
                              Short-Term Federal             Low       High      Very Low      Low
                              Short-Term Corporate           Low       High        Low      Negligible
                            ---------------------------------------------------------------------------
                              Intermediate-Term            Medium      Medium   Negligible  Negligible
                                 U.S. Treasury
                              GNMA                         Medium      Medium   Negligible     High
                              Intermediate-Term Corporate  Medium      Medium      Low         Low
                            ---------------------------------------------------------------------------
                              Long-Term U.S. Treasury       High        Low     Negligible  Negligible
                              Long-Term Corporate           High        Low        Low        Medium
                            ---------------------------------------------------------------------------
                              High Yield Corporate         Medium      Medium   Very High     Medium
                            ---------------------------------------------------------------------------
</TABLE>
 
- --------------------------------------------------------------------------------
THE VANGUARD
GROUP                 The Fund is a member of The Vanguard Group of Investment
                      Companies, a group of more than 30 investment companies
                      with more than 95 distinct investment portfolios and total
                      assets in excess of $370 billion. The Vanguard Group, Inc.
                      ("Vanguard"), a subsidiary jointly owned by the Vanguard
                      funds, provides all corporate management, administrative,
                      distribution, and shareholder accounting services on an
                      at-cost basis to the funds in the Group. As a result,
                      Vanguard's operating expenses are substantially lower than
                      those of the mutual fund industry.                 PAGE 28
- --------------------------------------------------------------------------------
INVESTMENT
ADVISERS              Wellington Management Company, LLP serves as investment
                      adviser to the GNMA, Long-Term Corporate and High Yield
                      Corporate Portfolios. Vanguard's Fixed Income Group
                      provides investment advisory services on an at-cost basis
                      to the three Short-Term Portfolios, the two
                      Intermediate-Term Portfolios and the Long-Term U.S.
                      Treasury Portfolio.                                PAGE 29
- --------------------------------------------------------------------------------
DIVIDEND POLICY       Each Portfolio declares a dividend each business day based
                      on its ordinary income. Dividends are paid on the first
                      business day of each month. Net capital gains (excess of
                      long- and short-term capital gains over capital losses),
                      if any, will be distributed annually. Dividends and
                      capital gains distributions are automatically reinvested
                      in additional shares.                              PAGE 32
- --------------------------------------------------------------------------------
 
                                        3
<PAGE>   50
 
SPECIAL
CONSIDERATIONS        (1) Each Portfolio, except the Short-Term Federal
                      Portfolio, may invest a portion of its assets in bond
                      (interest rate) futures contracts and options. Each
                      Portfolio may hold restricted securities. The Short-Term
                      Corporate, Intermediate-Term Corporate, Long-Term
                      Corporate, and High Yield Corporate Portfolios may invest
                      in securities of foreign issuers.                  PAGE 24
 
                      (2) Each Portfolio may lend its securities.        PAGE 25
- --------------------------------------------------------------------------------
 
                                        4
<PAGE>   51
 
   
FUND EXPENSES         The following table illustrates ALL expenses and fees that
                      you would incur as a shareholder of the Fund. These
                      expenses and fees are based upon those incurred for the
                      fiscal year ended January 31, 1998.
    
 
   
<TABLE>
<CAPTION>
                                                   SHORT-TERM        SHORT-        SHORT-        INTERMEDIATE-
                                                      U.S.            TERM          TERM             TERM
                                                    TREASURY        FEDERAL      CORPORATE       U.S. TREASURY
       SHAREHOLDER TRANSACTION EXPENSES             PORTFOLIO      PORTFOLIO     PORTFOLIO         PORTFOLIO
- ----------------------------------------------------------------------------------------------------------------
<S>                                               <C>              <C>           <C>           <C>
Sales Load Imposed on Purchases...............    None             None          None          None
Sales Load Imposed on Reinvested Dividends....    None             None          None          None
Redemption Fees*..............................    None             None          None          None
Exchange Fees.................................    None             None          None          None

<CAPTION>
                                                                     SHORT-        SHORT-        INTERMEDIATE-
                                                   SHORT-TERM         TERM          TERM             TERM
                                                  U.S. TREASURY     FEDERAL      CORPORATE       U.S. TREASURY
        ANNUAL FUND OPERATING EXPENSES              PORTFOLIO      PORTFOLIO     PORTFOLIO**       PORTFOLIO
- ----------------------------------------------------------------------------------------------------------------
Management & Administrative Expenses..........    0.21%            0.21%         0.23%         0.21%
Investment Advisory Fees......................    0.02             0.01          0.01          0.01
12b-1 Fees....................................    None             None          None          None
Other Expenses
  Distribution Costs..........................    0.03%            0.03%         0.03%         0.03%
  Miscellaneous Expenses......................    0.01             0.02          0.01          0.02
                                                 -----            -----         -----         -----
Total Other Expenses..........................    0.04             0.05          0.04          0.05
                                                 -----            -----         -----         -----
         TOTAL OPERATING EXPENSES.............    0.27%            0.27%         0.28%         0.27%
                                                 =====            =====         =====         =====
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                          INTERMEDIATE-       LONG-TERM       LONG-        HIGH
                                                              TERM              U.S.          TERM        YIELD
                                              GNMA          CORPORATE         TREASURY      CORPORATE   CORPORATE
    SHAREHOLDER TRANSACTION EXPENSES        PORTFOLIO       PORTFOLIO         PORTFOLIO     PORTFOLIO   PORTFOLIO
- ------------------------------------------------------------------------------------------------------------------
<S>                                         <C>         <C>                 <C>             <C>         <C>
Sales Load Imposed on Purchases..........   None        None                None            None           None
Sales Load Imposed on Reinvested
  Dividends..............................   None        None                None            None           None
Redemption Fees*.........................   None        None                None            None            1%+
Exchange Fees............................   None        None                None            None           None
</TABLE>
    
 
<TABLE>
<CAPTION>
                                                  INTERMEDIATE-TERM     LONG-TERM     LONG-TERM   HIGH YIELD
                                        GNMA          CORPORATE       U.S. TREASURY   CORPORATE   CORPORATE
  ANNUAL FUND OPERATING EXPENSES      PORTFOLIO       PORTFOLIO         PORTFOLIO     PORTFOLIO   PORTFOLIO
- ------------------------------------------------------------------------------------------------------------
<S>                                   <C>         <C>                 <C>             <C>         <C>
Management & Administrative
  Expenses.........................   0.26%       0.20%               0.21%           0.26%       0.20%
Investment Advisory Fees...........   0.01        0.01                0.01            0.03        0.04
12b-1 Fees.........................   None        None                None            None        None
Other Expenses
  Distribution Costs...............   0.02%       0.03%               0.03%           0.02%       0.02%
  Miscellaneous Expenses...........   0.02        0.02                0.02            0.01        0.02
                                     -----       -----               -----           -----       -----
Total Other Expenses...............   0.04        0.05                0.05            0.03        0.04
                                     -----       -----               -----           -----       -----
         TOTAL OPERATING
           EXPENSES................   0.31%       0.26%               0.27%           0.32%       0.28%
                                     =====       =====               =====           =====       =====
</TABLE>
 
 * Wire redemptions of less than $5,000 are subject to a $5 processing fee.
 
 ** Expenses shown are for Short-Term Corporate Portfolio's Investor Shares.
 
   
 + The 1% fee withheld from redemption proceeds on shares redeemed or exchanged
   within one year of purchase is paid to the Portfolio.
    
                                        5
<PAGE>   52
 
                      The purpose of this table is to assist you in
                      understanding the various costs and expenses that an
                      investor would bear directly or indirectly as a
                      shareholder in the Fund.
 
                      The following example illustrates the expenses that you
                      would incur on a $1,000 investment over various periods,
                      assuming (1) a 5% annual rate of return and (2) redemption
                      at the end of each period.
 
<TABLE>
<CAPTION>
                                                                                1         3         5         10
                                                                               YEAR     YEARS     YEARS     YEARS
                                                                              -----     ------    ------    -------
                               <S>                                            <C>      <C>       <C>       <C>
                               Short-Term U.S. Treasury Portfolio...........    $3       $ 9       $15       $34
                               Short-Term Federal Portfolio.................    $3       $ 9       $15       $34
                               Short-Term Corporate Portfolio--Investor
                                 Shares.....................................    $3       $ 9       $16       $36
                               Intermediate-Term U.S. Treasury Portfolio....    $3       $ 9       $15       $34
                               Intermediate-Term Corporate Portfolio........    $3       $ 8       $15       $33
                               GNMA Portfolio...............................    $3       $10       $17       $39
                               Long-Term U.S. Treasury Portfolio............    $3       $ 9       $15       $34
                               Long-Term Corporate Portfolio................    $3       $10       $18       $41
                               High Yield Corporate Portfolio...............    $3       $ 9       $16       $36
</TABLE>
 
                      THIS EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF
                      PAST OR FUTURE EXPENSES OR PERFORMANCE. ACTUAL EXPENSES
                      MAY BE HIGHER OR LOWER THAN THOSE SHOWN.
- --------------------------------------------------------------------------------
FINANCIAL
HIGHLIGHTS            The following financial highlights for a share outstanding
                      throughout each period have been derived from financial
                      statements which were audited by Price Waterhouse LLP,
                      independent accountants, whose reports on the financial
                      statements which contain this information were
                      unqualified. This information should be read in
                      conjunction with the Fund's financial statements and notes
                      thereto, which, together with the remaining portions of
                      the Fund's 1998 Annual Report to Shareholders, are
                      incorporated by reference in the Statement of Additional
                      Information and in this Prospectus, and which appear,
                      along with the reports of Price Waterhouse LLP, in the
                      Fund's 1998 Annual Report to Shareholders. For a more
                      complete discussion of the Fund's performance, please see
                      the Fund's 1998 Annual Report to Shareholders which may be
                      obtained without charge by writing to the Fund or by
                      calling Participant Services at 1-800-523-1188.
 
                                        6
<PAGE>   53
 
   
<TABLE>
<CAPTION>
                                                           ----------------------------------------------------------------------
                                                                             SHORT-TERM U.S. TREASURY PORTFOLIO
                                                           ----------------------------------------------------------------------
                                                                         YEAR ENDED JANUARY 31,
                                                           ---------------------------------------------------    OCT. 28, 1991+
                                                            1998     1997     1996     1995     1994     1993    TO JAN. 31, 1992
<S>                                                        <C>      <C>      <C>      <C>      <C>      <C>      <C>
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF PERIOD.....................  $10.16   $10.36    $9.89   $10.41   $10.41   $10.12        $10.00
                                                           ------   ------   ------   ------   ------   ------   -----------
INVESTMENT OPERATIONS
  Net Investment Income..................................    .590     .586     .625     .532     .486     .528          .140
  Net Realized and Unrealized Gain (Loss) on
    Investments..........................................    .110    (.200)    .470    (.500)    .079     .332          .120
                                                           ------   ------   ------   ------   ------   ------   -----------
    TOTAL FROM INVESTMENT OPERATIONS.....................    .700     .386    1.095     .032     .565     .860          .260
- ---------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment Income...................   (.590)   (.586)   (.625)   (.532)   (.486)   (.528)        (.140)
  Distributions from Realized Capital Gains..............      --       --       --    (.020)   (.079)   (.042)           --
                                                           ------   ------   ------   ------   ------   ------   -----------
    TOTAL DISTRIBUTIONS..................................   (.590)   (.586)   (.625)   (.552)   (.565)   (.570)        (.140)
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD...........................  $10.27   $10.16   $10.36    $9.89   $10.41   $10.41        $10.12
=================================================================================================================================
TOTAL RETURN.............................................    7.11%    3.89%   11.37%    0.40%    5.54%    8.74%         2.60%
=================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Period (Millions).....................  $1,009     $970     $919     $754     $729     $526               $102
Ratio of Total Expenses to Average Net Assets............    0.27%    0.25%    0.27%    0.28%    0.26%    0.26%         0.26%*
Ratio of Net Investment Income to Average Net Assets.....    5.80%    5.77%    6.14%    5.33%    4.64%    5.12%         5.22%*
Portfolio Turnover Rate..................................      83%      86%      93%     126%      86%      71%           40%
</TABLE>
    
 
* Annualized.
+ Commencement of operations.
 
   
<TABLE>
<CAPTION>
                                      -------------------------------------------------------------------------------------------
                                                                     SHORT-TERM FEDERAL PORTFOLIO
                                      -------------------------------------------------------------------------------------------
                                                                        YEAR ENDED JANUARY 31,
                                      -------------------------------------------------------------------------------------------
                                       1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                   <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR..............................  $10.11   $10.28    $9.79   $10.38   $10.38   $10.31   $10.08    $9.89    $9.78   $10.05
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
INVESTMENT OPERATIONS
  Net Investment Income.............    .611     .615     .601     .550     .522     .609     .720     .801     .842     .817
  Net Realized and Unrealized Gain
    (Loss) on Investments...........    .080    (.170)    .490    (.580)    .110     .232     .307     .190     .110    (.270)
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL FROM INVESTMENT
      OPERATIONS....................    .691     .445    1.091    (.030)    .632     .841    1.027     .991     .952     .547
- ---------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment
    Income..........................   (.611)   (.615)   (.601)   (.550)   (.522)   (.609)   (.720)   (.801)   (.842)   (.817)
  Distributions from Realized
    Capital Gains...................      --       --       --    (.010)   (.110)   (.162)   (.077)      --       --       --
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL DISTRIBUTIONS.............   (.611)   (.615)   (.601)   (.560)   (.632)   (.771)   (.797)   (.801)   (.842)   (.817)
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR........  $10.19   $10.11   $10.28    $9.79   $10.38   $10.38   $10.31   $10.08    $9.89    $9.78
=================================================================================================================================
TOTAL RETURN........................    7.06%    4.51%   11.43%   (0.21)%   6.23%    8.49%   10.59%   10.46%   10.09%    5.66%
=================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions)........................  $1,460   $1,348   $1,402   $1,474   $1,936   $1,688   $1,274     $508     $228     $159
Ratio of Total Expenses to Average
  Net Assets........................    0.27%    0.25%    0.27%    0.28%    0.26%    0.27%    0.26%    0.30%    0.28%    0.32%
Ratio of Net Investment Income to
  Average Net Assets................    6.04%    6.09%    5.93%    5.53%    4.98%    5.88%    6.98%    8.06%    8.59%    8.50%
Portfolio Turnover Rate.............      94%      57%      74%      57%      49%      70%     111%     141%     133%     228%
</TABLE>
    
 
                                        7
<PAGE>   54
 
   
<TABLE>
<CAPTION>
                                      -------------------------------------------------------------------------------------------
                                                           SHORT-TERM CORPORATE PORTFOLIO -- INVESTOR SHARES
                                      -------------------------------------------------------------------------------------------
                                                                        YEAR ENDED JANUARY 31,
                                      -------------------------------------------------------------------------------------------
                                       1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                   <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR..............................  $10.75   $10.94   $10.40   $10.94   $10.99   $10.88   $10.50   $10.34   $10.23   $10.43
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
INVESTMENT OPERATIONS
  Net Investment Income.............    .664     .663     .671     .596     .605     .695     .804     .876     .895     .833
  Net Realized and Unrealized Gain
    (Loss) on Investments...........    .120    (.190)    .540    (.540)    .049     .275     .380     .160     .110    (.200)
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL FROM INVESTMENT
      OPERATIONS....................    .784     .473    1.211     .056     .654     .970    1.184    1.036    1.005     .633
- ---------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment
    Income..........................   (.664)   (.663)   (.671)   (.596)   (.605)   (.695)   (.804)   (.876)   (.895)   (.833)
  Distributions from Realized
    Capital Gains...................      --       --       --       --    (.099)   (.165)      --       --       --       --
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL DISTRIBUTIONS.............   (.664)   (.663)   (.671)   (.596)   (.704)   (.860)   (.804)   (.876)   (.895)   (.833)
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR........  $10.87   $10.75   $10.94   $10.40   $10.94   $10.99   $10.88   $10.50   $10.34   $10.23
=================================================================================================================================
TOTAL RETURN........................    7.53%    4.52%   11.95%    0.60%    6.11%    9.29%   11.70%   10.47%   10.18%    6.31%
=================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions)........................  $4,709   $4,531   $3,873   $2,924   $3,573   $2,811   $1,911     $829     $597     $493
Ratio of Total Expenses to Average
  Net Assets........................    0.28%    0.25%    0.27%    0.28%    0.26%    0.27%    0.26%    0.31%    0.28%    0.34%
Ratio of Net Investment Income to
  Average Net Assets................    6.17%    6.18%    6.23%    5.66%    5.48%    6.33%    7.44%    8.48%    8.70%    8.17%
Portfolio Turnover Rate.............      45%      45%      62%      69%      61%      71%      99%     107%     121%     165%
</TABLE>
    
 
   
<TABLE>
<CAPTION>
                                                 -----------------------------------------------------------------------
                                                                INTERMEDIATE-TERM U.S. TREASURY PORTFOLIO
                                                 -----------------------------------------------------------------------
                                                               YEAR ENDED JANUARY 31,
                                                 ---------------------------------------------------   OCT. 28, 1991+ TO
                                                  1998     1997     1996     1995     1994     1993      JAN. 31, 1992
<S>                                              <C>      <C>      <C>      <C>      <C>      <C>      <C>
- ------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF PERIOD...........  $10.37   $10.90    $9.76   $10.82   $10.79   $10.19        $10.00
                                                 ------   ------    -----   ------   ------   ------   ------------
INVESTMENT OPERATIONS
  Net Investment Income........................    .647     .649     .662     .603     .617     .676          .170
  Net Realized and Unrealized Gain (Loss) on
    Investments................................    .430    (.530)   1.140   (1.033)    .443     .617          .190
                                                 ------   ------   ------   ------   ------   ------   ------------
    TOTAL FROM INVESTMENT OPERATIONS...........   1.077     .119    1.802    (.430)   1.060    1.293          .360
- ------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment Income.........   (.647)   (.649)   (.662)   (.603)   (.617)   (.676)        (.170)
  Distributions from Realized Capital Gains....      --       --       --    (.027)   (.413)   (.017)           --
                                                 ------   ------   ------   ------   ------   ------   ------------
    TOTAL DISTRIBUTIONS........................   (.647)   (.649)   (.662)   (.630)  (1.030)   (.693)        (.170)
- ------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD.................  $10.80   $10.37   $10.90    $9.76   $10.82   $10.79        $10.19
========================================================================================================================
TOTAL RETURN...................................   10.78%    1.28%   18.96%   (3.90)%  10.09%   13.14%         3.59%
========================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Period (Millions)...........  $1,595   $1,279   $1,226     $848   $1,007     $673          $190
Ratio of Total Expenses to Average Net
  Assets.......................................    0.27%    0.25%    0.28%    0.28%    0.26%    0.26%         0.26%*
Ratio of Net Investment Income to Average Net
  Assets.......................................    6.19%    6.26%    6.34%    6.05%    5.55%    6.44%         6.47%*
Portfolio Turnover Rate........................      30%      42%      56%     128%     118%     123%           32%
</TABLE>
    
 
* Annualized.
+ Commencement of operations.
 
                                        8
<PAGE>   55
 
<TABLE>
<CAPTION>
                                      -------------------------------------------------------------------------------------------
                                                                            GNMA PORTFOLIO
                                      -------------------------------------------------------------------------------------------
                                                                        YEAR ENDED JANUARY 31,
                                      -------------------------------------------------------------------------------------------
                                       1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                   <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR..............................  $10.23   $10.45    $9.71   $10.39   $10.50   $10.25    $9.85    $9.54    $9.34    $9.69
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------    -----
INVESTMENT OPERATIONS
  Net Investment Income.............    .718     .727     .734     .693     .641     .778     .831     .855     .878     .882
  Net Realized and Unrealized Gain
    (Loss) on Investments...........    .253    (.220)    .740    (.673)   (.110)    .250     .400     .310     .200    (.350)
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------    -----
    TOTAL FROM INVESTMENT
      OPERATIONS....................    .971     .507    1.474     .020     .531    1.028    1.231    1.165    1.078     .532
- ---------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment
    Income..........................   (.718)   (.727)   (.734)   (.693)   (.641)   (.778)   (.831)   (.855)   (.878)   (.882)
  Distributions from Realized
    Capital Gains...................   (.003)      --       --    (.007)      --       --       --       --       --       --
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------    -----
    TOTAL DISTRIBUTIONS.............   (.721)   (.727)   (.734)   (.700)   (.641)   (.778)   (.831)   (.855)   (.878)   (.882)
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR........  $10.48   $10.23   $10.45    $9.71   $10.39   $10.50   $10.25    $9.85    $9.54    $9.34
=================================================================================================================================
TOTAL RETURN........................    9.86%    5.15%   15.64%    0.36%    5.18%   10.40%   13.00%   12.85%   11.98%    5.80%
=================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions)........................  $8,894   $7,400   $6,998   $5,851   $7,043   $7,167   $5,207   $2,711   $2,128   $1,907
Ratio of Total Expenses to Average
  Net Assets........................    0.31%    0.27%    0.29%    0.30%    0.28%    0.29%    0.29%    0.34%    0.31%    0.35%
Ratio of Net Investment Income to
  Average Net Assets................    6.97%    7.16%    7.22%    7.04%    6.19%    7.38%    8.22%    8.95%    9.25%    9.35%
Portfolio Turnover Rate.............       3%      12%       7%      35%       2%       7%       1%       1%       9%       8%
</TABLE>
 
<TABLE>
<CAPTION>
                                                              ---------------------------------------------------------
                                                                        INTERMEDIATE-TERM CORPORATE PORTFOLIO
                                                              ---------------------------------------------------------
                                                                     YEAR ENDED JANUARY 31,
                                                              ------------------------------------    NOV. 1, 1993,+ TO
                                                               1998      1997      1996      1995       JAN. 31, 1994
<S>                                                           <C>       <C>       <C>       <C>       <C>
- -----------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF PERIOD........................   $9.72    $10.17     $9.07    $10.04         $10.00
                                                              ------    ------    ------    ------    ------------
INVESTMENT OPERATIONS
  Net Investment Income.....................................    .638      .639      .658      .587           .125
  Net Realized and Unrealized Gain (Loss) on Investments....    .321     (.430)    1.100     (.970)          .040
                                                              ------    ------    ------    ------    ------------
    TOTAL FROM INVESTMENT OPERATIONS........................    .959      .209     1.758     (.383)          .165
- -----------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment Income......................   (.638)    (.639)    (.658)    (.587)         (.125)
  Distributions from Realized Capital Gains.................   (.011)    (.020)       --        --             --
                                                              ------    ------    ------    ------    ------------
    TOTAL DISTRIBUTIONS.....................................   (.649)    (.659)    (.658)    (.587)         (.125)
- -----------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD..............................  $10.03     $9.72    $10.17     $9.07         $10.04
=======================================================================================================================
TOTAL RETURN................................................   10.24%     2.29%    19.94%    (3.73)%         1.66%
=======================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Period (Millions)........................    $899      $592      $424      $163            $85
Ratio of Total Expenses to Average Net Assets...............    0.26%     0.25%     0.28%     0.28%          0.25%*
Ratio of Net Investment Income to Average Net Assets........    6.51%     6.61%     6.70%     6.46%          5.11%*
Portfolio Turnover Rate.....................................      69%       85%       78%       97%            74%
</TABLE>
 
* Annualized.
+ Commencement of operations.
 
                                        9
<PAGE>   56
 
<TABLE>
<CAPTION>
                                      ------------------------------------------------------------------------------------------
                                                                  LONG-TERM U.S. TREASURY PORTFOLIO
                                      ------------------------------------------------------------------------------------------
                                                                        YEAR ENDED JANUARY 31,
                                      ------------------------------------------------------------------------------------------
                                       1998     1997     1996     1995     1994     1993     1992     1991     1990    1989
<S>                                   <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>   <C>
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR..............................   $9.84   $10.73    $9.23   $10.75   $10.04   $10.14    $9.74    $9.53    $9.28   $9.49
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   -----
INVESTMENT OPERATIONS
  Net Investment Income.............    .643     .655     .669     .665     .685     .733     .763     .776     .781    .778
  Net Realized and Unrealized Gain
    (Loss) on Investments...........    .950    (.877)   1.725   (1.401)    .886     .600     .400     .210     .250   (.210)
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   -----
    TOTAL FROM INVESTMENT
      OPERATIONS....................   1.593    (.222)   2.394    (.736)   1.571    1.333    1.163     .986    1.031    .568
- --------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment
    Income..........................   (.643)   (.655)   (.669)   (.665)   (.685)   (.733)   (.763)   (.776)   (.781)  (.778)
  Distributions from Realized
    Capital Gains...................      --    (.013)   (.225)   (.119)   (.176)   (.700)      --       --       --      --
                                      ------   ------   ------   ------   ------   ------   ------   ------   ------   -----
    TOTAL DISTRIBUTIONS.............   (.643)   (.668)   (.894)   (.784)   (.861)  (1.433)   (.763)   (.776)   (.781)  (.778)
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR........  $10.79    $9.84   $10.73    $9.23   $10.75   $10.04   $10.14    $9.74    $9.53   $9.28
================================================================================================================================
TOTAL RETURN........................   16.85%   (1.85)%  26.72%   (6.68)%  16.09%   14.12%   12.44%   11.00%   11.33%   6.43%
================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions)........................  $1,061     $898     $916     $671     $829     $874     $833     $722     $456    $172
Ratio of Total Expenses to Average
  Net Assets........................    0.27%    0.25%    0.27%    0.28%    0.26%    0.27%    0.26%    0.30%    0.28%   0.36%
Ratio of Net Investment Income to
  Average Net Assets................    6.38%    6.66%    6.57%    7.02%    6.44%    7.26%    7.72%    8.29%    8.08%   8.46%
Portfolio Turnover Rate.............      18%      31%     105%      85%       7%     170%      89%     147%      83%    387%
</TABLE>
 
<TABLE>
<CAPTION>
                                     -------------------------------------------------------------------------------------------
                                                                    LONG-TERM CORPORATE PORTFOLIO
                                     -------------------------------------------------------------------------------------------
                                                                       YEAR ENDED JANUARY 31,
                                     -------------------------------------------------------------------------------------------
                                      1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                  <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR.............................   $8.71    $9.43    $8.18    $9.36    $9.04    $8.63    $8.02    $8.00    $7.91    $8.11
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
INVESTMENT OPERATIONS
  Net Investment Income............    .613     .619     .627     .617     .632     .680     .706     .720     .732     .741
  Net Realized and Unrealized Gain
    (Loss) on Investments..........    .685    (.566)   1.250   (1.108)    .579     .561     .610     .020     .090    (.200)
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL FROM INVESTMENT
      OPERATIONS...................   1.298     .053    1.877    (.491)   1.211    1.241    1.316     .740     .822     .541
- --------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment
    Income.........................   (.613)   (.619)   (.627)   (.617)   (.632)   (.680)   (.706)   (.720)   (.732)   (.741)
  Distributions from Realized
    Capital Gains..................   (.075)   (.154)      --    (.072)   (.259)   (.151)      --       --       --       --
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL DISTRIBUTIONS............   (.688)   (.773)   (.627)   (.689)   (.891)   (.831)   (.706)   (.720)   (.732)   (.741)
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR.......   $9.32    $8.71    $9.43    $8.18    $9.36    $9.04    $8.63    $8.02    $8.00    $7.91
================================================================================================================================
TOTAL RETURN.......................   15.52%    0.86%   23.64%   (5.12)%  13.83%   15.06%   17.09%    9.81%   10.67%    7.13%
================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions).......................  $3,720   $3,324   $3,376   $2,607   $3,166   $2,763   $1,992   $1,254     $954     $734
Ratio of Total Expenses to Average
  Net Assets.......................    0.32%    0.28%    0.31%    0.32%    0.30%    0.31%    0.31%    0.37%    0.34%    0.38%
Ratio of Net Investment Income to
  Average Net Assets...............    6.87%    7.06%    7.03%    7.37%    6.71%    7.68%    8.46%    9.16%    9.07%    9.40%
Portfolio Turnover Rate............      33%      30%      49%      43%      77%      50%      72%      62%      70%      60%
</TABLE>
 
                                       10
<PAGE>   57
 
<TABLE>
<CAPTION>
                                        ----------------------------------------------------------------------------------------
                                                                     HIGH YIELD CORPORATE PORTFOLIO
                                        ----------------------------------------------------------------------------------------
                                                                         YEAR ENDED JANUARY 31,
                                        ----------------------------------------------------------------------------------------
                                        1998    1997    1996     1995     1994     1993     1992     1991     1990     1989
<S>                                     <C>     <C>     <C>     <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF YEAR....  $7.87   $7.89   $7.24    $8.14    $7.56    $7.27    $6.19    $7.31    $8.44    $8.53
                                        -----   -----   -----    -----    -----    -----   ------    -----    -----    -----
INVESTMENT OPERATIONS
  Net Investment Income...............   .688    .688    .678     .679     .695     .727     .770     .904    1.004    1.016
  Net Realized and Unrealized Gain
    (Loss) on Investments.............   .300   (.020)   .650    (.900)    .580     .290    1.080   (1.120)  (1.130)   (.090)
                                        -----   -----   -----    -----    -----    -----   ------    -----    -----    -----
    TOTAL FROM INVESTMENT
      OPERATIONS......................   .988    .668   1.328    (.221)   1.275    1.017    1.850    (.216)   (.126)    .926
- --------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment
    Income............................  (.688)  (.688)  (.678)   (.679)   (.695)   (.727)   (.770)   (.904)  (1.004)  (1.016)
  Distributions from Realized
    Capital Gains.....................     --      --      --       --       --       --       --       --       --       --
                                        -----   -----   -----    -----    -----    -----   ------    -----    -----    -----
    TOTAL DISTRIBUTIONS...............  (.688)  (.688)  (.678)   (.679)   (.695)   (.727)   (.770)   (.904)  (1.004)  (1.016)
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR..........  $8.17   $7.87   $7.89    $7.24    $8.14    $7.56    $7.27    $6.19    $7.31    $8.44
================================================================================================================================
TOTAL RETURN*.........................  13.14%   9.01%  19.01%   (2.52)%  17.54%   14.68%   31.27%   (3.21)%  (1.84)%  11.41%
================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year (Millions)....  $4,747  $3,674  $3,007  $2,162   $2,625   $2,184   $1,593     $699     $828   $1,234
Ratio of Total Expenses to Average Net
  Assets..............................   0.28%   0.29%   0.34%    0.34%    0.32%    0.34%    0.34%    0.40%    0.38%    0.41%
Ratio of Net Investment Income to
  Average Net Assets..................   8.63%   8.92%   8.85%    9.13%    8.81%    9.82%   11.13%   13.35%   12.56%   12.07%
Portfolio Turnover Rate...............     45%     23%     38%      33%      51%      83%      44%      61%      41%      48%
</TABLE>
 
* Returns exclude 1% fee applied to shares redeemed or exchanged within one year
of purchase.
- --------------------------------------------------------------------------------
 
YIELD AND TOTAL
RETURN                From time to time a Portfolio may advertise its yield and
                      total return. Both yield and total return figures are
                      based on historical earnings and are not intended to
                      indicate future performance. The "total return" of a
                      Portfolio refers to the average annual compounded rates of
                      return over one-, five- and ten-year periods or for the
                      life of the Portfolio (as stated in the advertisement)
                      that would equate an initial amount invested at the
                      beginning of a stated period to the ending redeemable
                      value of the investment, assuming the reinvestment of all
                      dividends and capital gains distributions.
 
                      In accordance with industry guidelines set forth by the
                      U.S. Securities and Exchange Commission, the "30-day
                      yield" of a Portfolio is calculated by dividing net
                      investment income per share earned during a 30-day period
                      by the net asset value per share on the last day of the
                      period. Net investment income includes interest and
                      dividend income earned on the Portfolio's securities; it
                      is net of all expenses and all recurring and nonrecurring
                      charges that have been applied to all shareholder
                      accounts. The yield calculation assumes that net
                      investment income earned over 30 days is compounded
                      monthly for six months and then annualized. Methods used
                      to calculate advertised yields are standardized for all
                      stock and bond mutual funds. However, these methods differ
                      from the accounting methods used by a Portfolio to
                      maintain its books and records, and so the advertised
                      30-day yield may not fully reflect the income paid to an
                      investor's account or the yield reported in the
                      Portfolio's Reports to Shareholders.
 
                                       11
<PAGE>   58
 
                      Additionally, a Portfolio may compare its performance to
                      that of the Lehman Aggregate Bond Index, and may advertise
                      its duration, a measure of a Portfolio's sensitivity to
                      interest rate changes.
- --------------------------------------------------------------------------------
 
INVESTMENT
OBJECTIVE
THE FUND SEEKS TO
PROVIDE A HIGH LEVEL
OF CURRENT INCOME     The Fund is an open-end diversified investment company.
                      The objective of the Fund is to provide investors with a
                      high level of current income consistent with the
                      maintenance of principal and liquidity.
 
                      The Fund consists of nine distinct Portfolios, each of
                      which invests in fixed income securities within prescribed
                      maturity and quality standards. There is no assurance that
                      the Fund will achieve its stated objective.
 
                      The investment objective for the Fund is not fundamental
                      and so may be changed by the Board of Directors without
                      shareholder approval. Any such change could result in the
                      Fund having investment objectives different from the
                      objectives which a shareholder considered appropriate at
                      the time of investment in the Fund. However, shareholders
                      would be notified prior to any material change in the
                      Fund's objective.
- --------------------------------------------------------------------------------
 
INVESTMENT
POLICIES              While all of the Fund's Portfolios invest in fixed income
                      securities, the individual Portfolios vary substantially
                      in terms of the type, credit quality, and average maturity
                      of the securities in which they invest. The Fund is
                      managed without regard to tax ramifications.
 
                      IMPORTANT NOTE: Five of the Portfolios invest in U.S.
                      Treasury or U.S. Government agency securities to minimize
                      credit risk. Examples of the Government agencies and
                      instrumentalities whose securities may be purchased by
                      these Portfolios include the Federal Home Loan Mortgage
                      Corporation, the Small Business Administration, the
                      Government Export Trust and the Overseas Private
                      Investment Corporation. Government securities may be
                      backed by (i) the full faith and credit of the United
                      States; (ii) the particular Government agency's ability to
                      borrow directly from the Treasury; (iii) some other type
                      of United States support; or (iv) the credit of the
                      issuing agency, only. As described below, each of the five
                      Portfolios which invests in U.S. Treasury or U.S.
                      Government agency securities is required to invest a
                      specified percentage of its assets in securities backed by
                      the full faith and credit of the United States. WHILE U.S.
                      TREASURY OR GOVERNMENT AGENCY SECURITIES PROVIDE
                      SUBSTANTIAL PROTECTION AGAINST CREDIT RISK, THEY DO NOT
                      PROTECT INVESTORS AGAINST PRICE CHANGES DUE TO CHANGING
                      INTEREST RATES. THE MARKET VALUES OF GOVERNMENT SECURITIES
                      ARE NOT GUARANTEED AND WILL FLUCTUATE. See "Investment
                      Risks" for additional information on these and other
                      important risks.
 
THREE PORTFOLIOS
INVEST IN SHORT-TERM
BONDS                 Three Portfolios of the Fund invest in short-term bonds.
                      THE SHORT-TERM U.S. TREASURY PORTFOLIO invests at least
                      85% of its assets in short-term securities backed by the
                      full faith and credit of the U.S. Government. Also, at
                      least 65% of the Portfolio's assets will be invested in
                      U.S. Treasury bills, notes and bonds. In an effort to
                      minimize fluctuations in market value, the Short-Term U.S.
                      Treasury Portfolio is expected to maintain a
                      dollar-weighted average maturity between one and three
                      years.
 
                                       12
<PAGE>   59
 
                      The balance of the Short-Term U.S. Treasury Portfolio's
                      assets may be invested in U.S. Treasury or U.S. Government
                      agency securities, as well as in repurchase agreements
                      collateralized by such securities. The Portfolio may also
                      invest in bond (interest rate) futures and options to a
                      limited extent. See "Implementation of Policies" for a
                      description of these investment practices of the
                      Portfolio.
 
                      THE SHORT-TERM FEDERAL PORTFOLIO invests primarily in U.S.
                      Government agency securities, which are debt obligations
                      issued or guaranteed by agencies or instrumentalities of
                      the U.S. Government. Such "agency" securities may not be
                      backed by the "full faith and credit" of the U.S.
                      Government. The Portfolio may also invest in U.S. Treasury
                      securities, as well as in repurchase agreements
                      collateralized by U.S. Treasury or U.S. Government agency
                      securities. In an effort to minimize fluctuations in
                      market value, the Short-Term Federal Portfolio is expected
                      to maintain a dollar-weighted average maturity between one
                      and three years. See "Implementation of Policies" for a
                      description of these and other investment practices of the
                      Portfolio.
 
                      THE SHORT-TERM CORPORATE PORTFOLIO invests in the
                      following investment grade fixed-income securities:
 
                      (1) Short-term and intermediate-term corporate debt
                      securities;
                      (2) U.S. Treasury and U.S. Government agency obligations;
                      (3) Obligations issued by state and municipal governments
                          and their agencies and instrumentalities;
                      (4) Bank obligations, including certificates of deposit
                      and bankers' acceptances;
                      (5) Commercial paper; and
                      (6) Repurchase agreements collateralized by these
                      securities.
 
                      Investment grade corporate debt securities are those rated
                      a minimum of Baa3 by Moody's Investors Service, Inc.
                      ("Moody's") or BBB- by Standard & Poor's Corporation
                      ("Standard & Poor's"). Investment grade commercial paper
                      is rated A-1 or better by Standard & Poor's or Prime-1 by
                      Moody's, or, if unrated, issued by a corporation having an
                      outstanding unsecured debt issue rated A or better by
                      Moody's or Standard & Poor's. At least 70% of the
                      Short-Term Corporate Portfolio's assets will be invested
                      in debt securities rated a minimum of A3 by Moody's or A-
                      by Standard & Poor's, and not more than 30% of the
                      Portfolio's assets may be invested in debt securities
                      rated Baa by Moody's or BBB by Standard & Poor's.
                      Securities rated Baa or BBB are considered medium grade
                      obligations. Interest payments and principal are regarded
                      as adequate for the present, but certain protective
                      elements found in higher-rated bonds may be lacking. Such
                      bonds lack outstanding investment characteristics and have
                      speculative characteristics.
 
                      In the event that a security held by the Portfolio is
                      downgraded, the Portfolio may continue to hold such
                      security until such time as the adviser deems it
                      advantageous to dispose of the security.
 
                      In an effort to minimize fluctuations in market value, the
                      Short-Term Corporate Portfolio is expected to maintain a
                      dollar-weighted average maturity between 1 and 3 years.
                      The Short-Term Corporate Portfolio may also hold
                      asset-backed securities, as well as securities of foreign
                      issuers provided such securities are denominated in
 
                                       13
<PAGE>   60
 
                      U.S. dollars. In addition, the Portfolio may invest in
                      bond (interest rate) futures and options to a limited
                      extent. See "Implementation of Policies" for a description
                      of these and other investment practices of the Portfolio.
 
   
THREE PORTFOLIOS
INVEST IN
INTERMEDIATE-TERM
BONDS                 THE INTERMEDIATE-TERM U.S. TREASURY PORTFOLIO invests at
                      least 85% of its assets in intermediate-term securities
                      backed by the full faith and credit of the U.S.
                      Government. Also, at least 65% of the Portfolio's assets
                      will be invested in U.S. Treasury bills, notes and bonds.
                      The dollar-weighted average maturity of the Portfolio is
                      expected to range from 5 to 10 years.
    
 
                      The balance of the Portfolio's assets may be invested in
                      U.S. Treasury or U.S. Government agency securities, as
                      well as in repurchase agreements collateralized by such
                      securities. The Portfolio may also invest in bond
                      (interest rate) futures and options to a limited extent.
                      See "Implementation of Policies" for a description of
                      these investment practices of the Portfolio.
 
                      THE GNMA PORTFOLIO invests at least 80% of its assets in
                      Government National Mortgage Association ("GNMA" or
                      "Ginnie Mae") pass-through certificates. The balance of
                      the Portfolio's assets may be invested in other U.S.
                      Treasury or U.S. Government agency securities, as well as
                      in repurchase agreements collateralized by such
                      securities. The Portfolio may also invest in bond
                      (interest rate) futures and options to a limited extent
                      and real estate mortgage conduits ("REMICs"). See
                      "Implementation of Policies" for a description of these
                      investment practices of the Portfolio.
 
                      GNMA pass-through certificates are mortgage-backed
                      securities representing part ownership of a pool of
                      mortgage loans. Monthly mortgage payments of both interest
                      and principal "pass through" from homeowners to
                      certificate investors, such as the GNMA Portfolio. The
                      GNMA Portfolio reinvests the principal portion in
                      additional securities and distributes the interest portion
                      as income to the Portfolio's shareholders. Under normal
                      circumstances, GNMA certificates are expected to provide
                      higher yields than U.S. Treasury securities of comparable
                      maturity.
 
                      The mortgage loans underlying GNMA certificates--issued by
                      lenders such as mortgage bankers, commercial banks, and
                      savings and loan associations--are either insured by the
                      Federal Housing Administration (FHA) or guaranteed by the
                      Veterans Administration (VA). Each pool of mortgage loans
                      must also be approved by GNMA, a U.S. Government
                      corporation within the U.S. Department of Housing and
                      Urban Development. Once GNMA approval is obtained, the
                      timely payment of interest and principal on each
                      underlying mortgage loan is guaranteed by the "full faith
                      and credit" of the U.S. Government.
 
                      Although stated maturities on GNMA certificates generally
                      range from 25 to 30 years, effective maturities are
                      usually much shorter due to the prepayment of the
                      underlying mortgages by homeowners. On average, GNMA
                      certificates are repaid within 12 years and so are
                      classified as intermediate-term securities.
 
                      THE INTERMEDIATE-TERM CORPORATE PORTFOLIO invests in a
                      diversified portfolio of investment grade corporate and
                      Government bonds. Under normal circumstances, at least 65%
                      of the Portfolio's assets are invested in straight debt
                      corporate bonds
 
                                       14
<PAGE>   61
 
                      rated a minimum of Baa3 by Moody's or BBB- by Standard &
                      Poor's at the time of purchase. Additionally, at least 80%
                      of the Portfolio's assets will normally be invested in a
                      combination of investment grade corporate bonds and
                      securities of the U.S. Government and its agencies and
                      instrumentalities. The Intermediate-Term Corporate
                      Portfolio is expected to maintain a dollar-weighted
                      average maturity between 5 and 10 years.
 
                      The preponderance of the Portfolio's holdings will be
                      classified in the top three credit-rating categories.
                      Specifically, at least 70% of the Portfolio's assets will
                      be invested in the following securities:
 
                      (1) Short-term and intermediate-term corporate debt
                          securities which at the time of purchase are rated a
                          minimum of A3 by Moody's or A- by Standard & Poor's;
 
                      (2) Securities issued by the U.S. Government, state and
                          municipal governments or their agencies and
                          instrumentalities;
 
                      (3) Commercial paper of companies having, at the time of
                          purchase, outstanding debt securities rated as
                          described in (1) or commercial paper rated P-1 or P-2
                          by Moody's or rated A-1 or A-2 by Standard & Poor's;
                          and
 
                      (4) Short-term fixed income securities held as cash
                          reserves, including U.S. Treasury or U.S. Government
                          agency securities, certificates of deposit, bankers'
                          acceptances, or repurchase agreements collateralized
                          by these securities.
 
                      Up to 30% of the Intermediate-Term Corporate Portfolio's
                      assets may be invested in straight debt securities rated
                      Baa by Moody's or BBB by Standard & Poor's (see page 13
                      for a description of these ratings), and in preferred
                      stocks and convertible securities. In the event that a
                      security held by the Portfolio is downgraded, the
                      Portfolio may continue to hold such security until such
                      time as the adviser deems it to be advantageous to dispose
                      of the security.
 
                      The Intermediate-Term Corporate Portfolio may also hold
                      asset-backed securities, as well as securities of foreign
                      issuers provided such securities are denominated in U.S.
                      dollars. The Portfolio may also invest in bond (interest
                      rate) futures and options to a limited extent. See
                      "Implementation of Policies" for a description of these
                      investment practices of the Portfolio.
 
TWO PORTFOLIOS INVEST
IN LONG-TERM BONDS    THE LONG-TERM U.S. TREASURY PORTFOLIO invests at least 85%
                      of its assets in long-term securities backed by the full
                      faith and credit of the U.S. Government. Also, at least
                      65% of the Portfolio's assets will be invested in U.S.
                      Treasury bills, notes and bonds. The dollar-weighted
                      average maturity of the Portfolio is expected to range
                      from 15 to 30 years.
 
                      The balance of the Portfolio's assets may be invested in
                      U.S. Treasury or U.S. Government agency securities, as
                      well as in repurchase agreements collateralized by such
                      securities. The Portfolio may also invest in bond
                      (interest rate) futures and options to a limited extent.
                      See "Implementation of Policies" for a description of
                      these investment practices of the Portfolio.
 
                                       15
<PAGE>   62
 
                      THE LONG-TERM CORPORATE PORTFOLIO invests in a diversified
                      portfolio of investment grade corporate and Government
                      bonds. Under normal circumstances, at least 65% of the
                      Portfolio's assets are invested in straight debt corporate
                      bonds rated a minimum of Baa3 by Moody's or BBB- by
                      Standard & Poor's at the time of purchase. Additionally,
                      at least 80% of the Portfolio's assets will normally be
                      invested in a combination of investment grade corporate
                      bonds and securities of the U.S. Government and its
                      agencies and instrumentalities. The dollar-weighted
                      average maturity of the Portfolio is expected to range
                      from 15 to 25 years.
 
                      The preponderance of the Portfolio's holdings will be
                      classified in the top three credit-rating categories.
                      Specifically, at least 70% of the Portfolio's assets will
                      be invested in the following securities:
 
                      (1) Straight debt corporate securities which at the time
                          of purchase are rated a minimum of A3 by Moody's or A-
                          by Standard & Poor's;
 
                      (2) Securities issued by the U.S. Government or its
                          agencies and instrumentalities;
 
                      (3) Commercial paper of companies having, at the time of
                          purchase, outstanding debt securities rated as
                          described in (1) or commercial paper rated P-1 or P-2
                          by Moody's or rated A-1 or A-2 by Standard & Poor's;
                          and
 
                      (4) Short-term fixed income securities held as cash
                          reserves, including U.S. Treasury or U.S. Government
                          agency securities, certificates of deposit, bankers'
                          acceptances, or repurchase agreements collateralized
                          by these securities.
 
                      Up to 30% of the Long-Term Corporate Portfolio's assets
                      may be invested in straight debt securities rated Baa by
                      Moody's or BBB by Standard & Poor's (see page 13 for a
                      description of these ratings), and in preferred stocks and
                      convertible securities. In addition, not more than 25% of
                      the Portfolio's assets may be invested in GNMA
                      certificates or other mortgage-backed securities. In the
                      event that a security held by the Portfolio is downgraded,
                      the Portfolio may continue to hold such security until
                      such time as the adviser deems it to be advantageous to
                      dispose of the security.
 
                      The Long-Term Corporate Portfolio may also hold
                      asset-backed securities, as well as U.S.
                      dollar-denominated debt securities issued by foreign
                      governments, their agencies and instrumentalities,
                      supranational entities and companies located outside the
                      U.S. The Portfolio may also invest in bond (interest rate)
                      futures and options to a limited extent. See
                      "Implementation of Policies" for a description of these
                      investment practices of the Portfolio.
 
ONE PORTFOLIO INVESTS
IN LOW-QUALITY,
HIGH-RISK BONDS       THE HIGH YIELD CORPORATE PORTFOLIO invests in a
                      diversified portfolio of high-yielding corporate debt
                      securities (so-called "junk bonds"). Under normal
                      circumstances, at least 80% of the Portfolio's assets will
                      be invested in high-yield corporate debt obligations rated
                      B or better by Moody's or Standard & Poor's. Not more than
                      20% of the High Yield Corporate Portfolio's assets may be
                      invested in debt securities which are rated less than B or
                      unrated, and convertible securities and preferred stocks.
                      The Portfolio may invest up to 25% of its assets in cash
                      reserves and U.S. Government securities (including
                      repurchase agreements collateralized by U.S.
 
                                       16
<PAGE>   63
 
                      Treasury or U.S. Government agency securities) under
                      unusual market conditions for temporary defensive
                      measures.
 
                      The High Yield Corporate Portfolio will not invest in
                      securities that, at the time of initial investment, are
                      rated less than Caa by Moody's or CCC by Standard &
                      Poor's. Securities that are subsequently downgraded in
                      quality below Caa or CCC may continue to be held by the
                      Portfolio, and will be sold only if the Portfolio's
                      adviser believes it would be advantageous to do so. In
                      addition, the credit quality of unrated securities
                      purchased by the Portfolio must be, in the opinion of the
                      Portfolio's adviser, at least equivalent to a Caa rating
                      by Moody's or a CCC rating by Standard & Poor's.
 
                      Securities rated less than Baa by Moody's or BBB by
                      Standard & Poor's are classified as non-investment grade
                      securities. Such securities carry a high degree of risk
                      and are considered speculative by the major credit rating
                      agencies. The following are excerpts from the Moody's and
                      Standard & Poor's definitions for speculative grade debt
                      obligations:
 
                        Moody's: Ba-rated bonds have "speculative elements,"
                        their future "cannot be considered assured," and
                        protection of principal and interest is "moderate" and
                        "not well safeguarded." B-rated bonds "lack
                        characteristics of a desirable investment" and the
                        assurance of interest or principal payments "may be
                        small." Caa-rated bonds are "of poor standing" and "may
                        be in default" or may have "elements of danger with
                        respect to principal or interest."
 
                        Standard & Poor's: BB-rated bonds have "less near-term
                        vulnerability to default" than B- or CCC-rated
                        securities but face "major ongoing
                        uncertainties . . . which may lead to inadequate
                        capacity" to pay interest or principal. B-rated bonds
                        have a "greater vulnerability to default" than BB-rated
                        bonds and the ability to pay interest or principal will
                        likely be impaired by adverse business conditions.
                        CCC-rated bonds have a "currently identifiable
                        vulnerability to default" and, without favorable
                        business conditions, will be unable to repay interest
                        and principal.
 
                      Credit quality in the high-yield bond market can change
                      suddenly and unexpectedly, and even recently-issued credit
                      ratings may not fully reflect the actual risks posed by a
                      particular high-yield security. For these reasons, it is
                      the High Yield Corporate Portfolio's policy not to rely
                      primarily on ratings issued by established credit rating
                      agencies, but to utilize such ratings in conjunction with
                      the adviser's own independent and ongoing review of credit
                      quality.
 
                      In the past, the High Yield Corporate Portfolio has not
                      invested in non-income-producing high-yield
                      securities -- such as zero coupon bonds, which pay
                      interest only at maturity, or payment-in-kind bonds, which
                      pay interest in the form of additional securities.
                      Although it has no present plans to do so, the Portfolio
                      may invest up to 5% of its assets in such securities in
                      the future.
 
                      The High Yield Corporate Portfolio may also hold
                      asset-backed securities, as well as U.S.
                      dollar-denominated debt-securities issued by foreign
                      governments, their agencies and instrumentalities,
                      supranational entities and companies located
 
                                       17
<PAGE>   64
 
                      outside the U.S. The Portfolio may also invest in bond
                      (interest rate) futures and options to a limited extent.
                      See "Implementation of Policies" for a description of
                      these investment practices of the Portfolio.
 
                                                 * * *
 
                      The Fund is responsible for voting the shares of all
                      securities it holds.
- --------------------------------------------------------------------------------
 
INVESTMENT RISKS
THE PORTFOLIOS ARE
SUBJECT PRIMARILY
TO INTEREST RATE,
INCOME, CREDIT AND
MANAGER RISK          As mutual funds investing in fixed income securities, the
                      Portfolios of the Fund are subject primarily to interest
                      rate, income, credit and manager risk. INTEREST RATE RISK
                      is the potential for a decline in bond prices due to
                      rising interest rates. In general, bond prices vary
                      inversely with interest rates. When interest rates rise,
                      bond prices generally fall. Conversely, when interest
                      rates fall, bond prices generally rise. The change in
                      price depends on several factors, including the bond's
                      maturity date. In general, bonds with longer maturities
                      are more sensitive to changes in interest rates than bonds
                      with shorter maturities.
 
                      These principles of interest rate risk also apply to U.S.
                      Treasury and U.S. Government agency securities. As with
                      other bond investments, U.S. Government securities will
                      rise and fall in value as interest rates change. A
                      SECURITY BACKED BY THE U.S. TREASURY OR THE FULL FAITH AND
                      CREDIT OF THE UNITED STATES IS GUARANTEED ONLY AS TO THE
                      TIMELY PAYMENT OF INTEREST AND PRINCIPAL WHEN HELD TO
                      MATURITY. THE CURRENT MARKET PRICES FOR SUCH SECURITIES
                      ARE NOT GUARANTEED AND WILL FLUCTUATE.
 
                      As an illustration of interest rate risk, the charts below
                      depict the effect of a one and two percentage point change
                      in interest rates on three bonds of varying maturities:
 
                       PERCENT CHANGE IN THE PRICE OF A PAR BOND YIELDING 7.5%
 
<TABLE>
<CAPTION>
                                                                 1 PERCENTAGE POINT   1 PERCENTAGE POINT
                                                                    INCREASE IN          DECREASE IN
                                       STATED MATURITY             INTEREST RATES       INTEREST RATES
                               -------------------------------   ------------------   ------------------
                               <S>                               <C>                  <C>
                               Short-Term (2.5 years)                  - 2.2%                + 2.3%
                               Intermediate-Term (10 years)            - 6.6%                + 7.3%
                               Long-Term (20 years)                    - 9.5%                +11.1%
</TABLE>
 
<TABLE>
<CAPTION>
                                                                 2 PERCENTAGE POINT   2 PERCENTAGE POINT
                                                                    INCREASE IN          DECREASE IN
                                       STATED MATURITY             INTEREST RATES       INTEREST RATES
                               -------------------------------   ------------------   ------------------
                               <S>                               <C>                  <C>
                               Short-Term (2.5 years)                  - 4.3%                + 4.6%
                               Intermediate-Term (10 years)            -12.7%                +15.2%
                               Long-Term (20 years)                    -17.8%                +24.1%
</TABLE>
 
                      These charts are intended to provide you with guidelines
                      for determining the degree of interest rate risk you may
                      be willing to assume. The yield and price changes shown
                      should not be taken as representative of a Portfolio's
                      current or future yield or expected changes in a
                      Portfolio's share price.
 
                                       18
<PAGE>   65
 
                      INCOME RISK is the potential for a decline in a
                      Portfolio's income due to falling market interest rates.
                      In relative terms, income risk will be higher for the
                      Fund's shorter-term Portfolios and lower for the Fund's
                      longer-term Portfolios.
 
                      Each Portfolio of the Fund is also subject to credit risk.
                      CREDIT RISK, also known as default risk, is the
                      possibility that a bond issuer will fail to make timely
                      payments of interest or principal to a Portfolio. The
                      credit risk of a Portfolio depends on the quality of its
                      investments. Reflecting their higher risks, lower-quality
                      bonds generally offer higher yields (all other factors
                      being equal).
 
                      Note: Unlike other Portfolios of the Fund, the High Yield
                      Corporate Portfolio holds speculative-grade investments
                      that pose substantial risks. Potential investors should
                      review the risk discussion below and the special risk
                      section on the High Yield Corporate Portfolio.
 
                      Besides interest rate risk and credit risk, investors are
                      exposed to PREPAYMENT RISK in the GNMA Portfolio and CALL
                      RISK in the Long-Term Corporate Portfolio.
 
                      Finally, the investment advisers manage the Portfolios
                      according to the traditional methods of "active"
                      investment management, which involve the buying and
                      selling of securities based upon economic, financial and
                      market analysis and investment judgment. MANAGER RISK
                      refers to the possibility that a Portfolio's investment
                      adviser may fail to execute the Portfolio's investment
                      strategy effectively. As a result, a Portfolio may fail to
                      achieve its stated objective.
 
THREE SHORT-TERM
PORTFOLIOS PROVIDE
MODERATE EXPOSURE TO
INTEREST RATE RISK    Interest rate risk for the SHORT-TERM U.S TREASURY
                      PORTFOLIO, the SHORT-TERM FEDERAL PORTFOLIO, and the
                      SHORT-TERM CORPORATE PORTFOLIO should be modest. Because
                      of their short-term average weighted maturities, the three
                      short-term Portfolios are expected to exhibit low to
                      moderate price fluctuations as interest rates change.
 
                      The three Portfolios differ principally in terms of credit
                      quality and potential yield. For the Short-Term U.S.
                      Treasury Portfolio, credit risk should be negligible. In
                      relative terms, credit risk will be slightly higher for
                      the Short-Term Federal Portfolio because of its holdings
                      of U.S. Government agency securities. (Even though they
                      carry top (Aaa) credit ratings, "agency" obligations are
                      not explicitly guaranteed by the U.S. Government and so
                      are perceived as somewhat riskier than comparable Treasury
                      bonds.)
 
                      With its corporate bond holdings, the Short-Term Corporate
                      Portfolio offers the highest exposure to credit risk of
                      the three short-term Portfolios. However, because of the
                      Portfolio's well-diversified holdings and emphasis on
                      high-quality bonds, overall credit risk should still be
                      quite low.
 
INTEREST RATE RISK
FOR THE THREE
INTERMEDIATE-TERM
PORTFOLIOS WILL BE
HIGHER                The three intermediate-term Portfolios are exposed to a
                      higher degree of interest rate risk than the three
                      short-term Portfolios. The INTERMEDIATE-TERM U.S. TREASURY
                      PORTFOLIO, the GNMA PORTFOLIO and the INTERMEDIATE-TERM
                      CORPORATE PORTFOLIO are expected to exhibit moderate to
                      high price fluctuations as interest rates change. Credit
                      risk, however, should be minimal for the Intermediate-Term
                      U.S.
 
                                       19
<PAGE>   66
 
                      Treasury and the GNMA Portfolios, as both Portfolios
                      invest primarily in "full faith and credit" securities of
                      the U.S. Government.
 
                      Due to its investments in corporate securities, credit
                      risk associated with the Intermediate-Term Corporate
                      Portfolio will be higher than for the other two
                      intermediate-term Portfolios. However, the
                      Intermediate-Term Corporate Portfolio's diversification
                      and quality of investments should help limit credit risk.
 
                      The GNMA Portfolio is unique among the Fund's Portfolios
                      in its exposure to prepayment risk. Prepayment risk is the
                      possibility that, as interest rates fall, homeowners are
                      more likely to refinance their home mortgages. When home
                      mortgages are refinanced, the principal on GNMA
                      Certificates held by the Portfolio is "prepaid" earlier
                      than expected. The GNMA Portfolio must then reinvest the
                      unanticipated principal in new GNMA certificates, just at
                      a time when interest rates on new mortgage investments are
                      falling.
 
                      Prepayment risk has two important effects on the GNMA
                      Portfolio:
 
                      - When interest rates fall and additional mortgage
                        prepayments must be reinvested at lower interest rates,
                        the income of the GNMA Portfolio will be reduced.
 
                      - When interest rates fall, prices on GNMA securities will
                        not rise as much as comparable Treasury bonds, as bond
                        market investors anticipate an increase in mortgage
                        prepayments and a likely decline in income.
 
                      In part to compensate for this risk, the GNMA Portfolio
                      will generally offer higher yields than a bond portfolio
                      of comparable quality -- such as the Intermediate-Term
                      U.S. Treasury Portfolio.
 
FOR THE TWO LONG-TERM
PORTFOLIOS, INTEREST
RATE RISK MAY BE
SUBSTANTIAL           The two long-term Portfolios are exposed to substantial
                      interest rate risk. The LONG-TERM U.S. TREASURY PORTFOLIO
                      and the LONG-TERM CORPORATE PORTFOLIO, both of which
                      maintain average maturities in excess of 15 years, may
                      exhibit high to very high price fluctuations due to
                      changing interest rates.
 
                      The main difference between the two Portfolios is credit
                      risk. The Long-Term U.S. Treasury Portfolio invests
                      primarily in "full faith and credit" U.S. Treasury bonds
                      for maximum credit protection, while the Long-Term
                      Corporate Portfolio invests in investment grade corporate
                      bonds for higher yields. Although credit risk for the
                      Long-Term Corporate Portfolio will be somewhat higher,
                      overall credit risk should still be low because of the
                      Portfolio's well-diversified holdings and its emphasis on
                      high-quality bonds.
 
                      An additional risk associated with the Long-Term Corporate
                      Portfolio is call risk. Call risk is the possibility that
                      corporate bonds held by the Portfolio will be repaid prior
                      to maturity. Call provisions, common in many corporate
                      bonds held by the Portfolio, allow bond issuers to redeem
                      bonds prior to maturity (at a specified price). When
                      interest rates are falling, bond issuers often exercise
                      these call provisions, paying off bonds that carry high
                      stated interest rates and often issuing new bonds at lower
                      rates. For the Portfolio, the result would be that bonds
                      with high interest
 
                                       20
<PAGE>   67
 
                      rates are "called" and must be replaced with
                      lower-yielding instruments. In these circumstances, the
                      income of the Portfolio would decline.
 
                      Reflecting these additional credit and call risks, the
                      Long-Term Corporate Portfolio will generally offer higher
                      yields than the Long-Term U.S. Treasury Portfolio.
 
THE HIGH YIELD
CORPORATE PORTFOLIO
POSES SUBSTANTIAL
RISKS                 The HIGH YIELD CORPORATE PORTFOLIO is unique among the
                      Portfolios of the Fund in its exposure to a substantial
                      degree of credit risk. The medium- and low-grade bonds
                      held by the Portfolio are considered speculative by
                      traditional investment standards. High-yield bonds may be
                      issued as a consequence of corporate restructurings, such
                      as leveraged buyouts, mergers, acquisitions, debt
                      recapitalizations, or similar events. Also, high-yield
                      bonds are often issued by smaller, less creditworthy
                      companies or by highly leveraged (indebted) firms, which
                      are generally less able than more financially stable firms
                      to make scheduled payments of interest and principal. The
                      risks posed by bonds issued under such circumstances are
                      substantial.
 
                      In an effort to minimize credit risk, the High Yield
                      Corporate Portfolio diversifies its holdings widely among
                      many issuers. As of January 31, 1998, the Portfolio held
                      securities of 171 corporate issuers, and the Portfolio's
                      holdings had the following credit quality characteristics:
 
<TABLE>
<CAPTION>
                                                                    PERCENT OF
                                                 INVESTMENT         INVESTMENTS
                                          ------------------------  -----------
                                          <S>                       <C>
                                          U.S. Treasury Securities       6%
                                          Cash Reserves                   3
                                          Corporate Bonds
                                            Aa/AA                         0
                                            Baa/BBB                       0
                                            Ba/BB                        36
                                            B                            55
                                            Caa/CC                        0
                                            Nonrated                      0
                                                                       ----
                                                                       100%
                                                                       ====
</TABLE>
 
                      In the past, the high yields from a portfolio of low-grade
                      bonds have more than compensated for the higher default
                      rates on such securities. However, there can be no
                      assurance that diversification will protect the Portfolio
                      from widespread bond defaults brought about by a sustained
                      economic downturn, or that yields will continue to offset
                      default rates on high-yield bonds in the future. A
                      long-term track record on bond default rates, such as that
                      for investment grade corporate bonds, does not exist for
                      the high-yield market. It may be that future default rates
                      on high-yield bonds will be more widespread and higher
                      than in the past, especially during periods of
                      deteriorating economic conditions.
 
                      The share price of the High Yield Corporate Portfolio will
                      be influenced not only by changing interest rates, but
                      also by the bond market's perception of credit quality and
                      the outlook for economic growth. When economic conditions
                      appear to be deteriorating, low- and medium-rated bonds
                      may decline in market value due to investors' heightened
                      concern over credit quality, regardless of prevailing
                      interest rates.
 
                                       21
<PAGE>   68
 
                      Especially at such times, trading in the secondary market
                      for high-yield bonds may become thin and market liquidity
                      may be significantly reduced. Even under normal
                      conditions, the market for high-yield bonds may be less
                      liquid than the market for investment grade corporate
                      bonds. There are fewer securities dealers in the high-
                      yield market, and purchasers of high-yield bonds are
                      concentrated among a smaller group of securities dealers
                      and institutional investors.
 
                      In periods of reduced market liquidity, high-yield bond
                      prices may become more volatile, and both the high-yield
                      market and the Portfolio may experience sudden and
                      substantial price declines. Also, there may be significant
                      disparities in the prices quoted for high-yield securities
                      by various dealers. Under such conditions, the Portfolio
                      may find it difficult to value its securities accurately.
                      The Portfolio may also be forced to sell securities at a
                      significant loss in order to meet shareholder redemptions.
 
                      Under unusual circumstances, the Portfolio may hold a
                      significant portion of its assets in U.S. Government
                      obligations and cash reserves for temporary defensive
                      purposes. As of January 31, 1998, for example, such
                      securities represented approximately 10% of the
                      Portfolio's assets.
 
                      Besides credit and liquidity concerns, prices for
                      high-yield bonds may be affected by legislative and
                      regulatory developments. For example, from time to time,
                      Congress has considered legislation to restrict or
                      eliminate the corporate tax deduction for interest
                      payments or to regulate corporate restructurings such as
                      takeovers or mergers. Such legislation may significantly
                      depress the prices of outstanding high-yield bonds.
 
                      Overall, investors should expect that the High Yield
                      Corporate Portfolio may fluctuate in price independently
                      of the broad bond market and prevailing interest rate
                      trends, and that price volatility at times may be very
                      high, especially as a result of credit concerns, market
                      liquidity, and anticipated or actual legislative and
                      regulatory changes.
- --------------------------------------------------------------------------------
 
WHO SHOULD
INVEST
INVESTORS SEEKING
CURRENT INCOME        The Fund is intended for investors who are seeking a high
                      level of current income from their investments. The Fund
                      is also suitable for investors with common stock holdings
                      who are seeking a complementary fixed income investment to
                      create a more diversified and balanced investment mix.
                      Because of potential fluctuations in the share price of
                      the Fund's Portfolios, the Fund may be inappropriate for
                      short-term investors who require maximum stability of
                      principal. Because of the risks associated with bond
                      investments, the Fund is intended to be a long-term
                      investment vehicle and is not designed to provide
                      investors with a means of speculating on short-term bond
                      market movements.
 
                      Investors who engage in excessive account activity
                      generate additional costs which are borne by all of the
                      Fund's shareholders. In order to minimize such costs the
                      Fund has adopted the following policies. The Fund reserves
                      the right to reject any purchase request (including
                      exchange purchases from other Vanguard portfolios) that is
                      reasonably deemed to be disruptive to efficient portfolio
                      management, either because of the timing of the investment
                      or previous excessive trading by the
 
                                       22
<PAGE>   69
 
                      investor. Additionally, the Fund reserves the right to
                      suspend the offering of its shares.
 
                      You should base your selection of a Portfolio (or
                      Portfolios) of the Fund on your own objectives, risk
                      preferences, and time horizon.
 
                      Three short-term Portfolios -- the SHORT-TERM U.S.
                      TREASURY PORTFOLIO, SHORT-TERM FEDERAL PORTFOLIO, and
                      SHORT-TERM CORPORATE PORTFOLIO -- are designed for
                      investors who are seeking yields that are more durable and
                      usually higher than those available from money market
                      funds, and who can tolerate modest fluctuations in the
                      value of their investment. The choice among the three is
                      one of credit quality -- U.S. Treasury, U.S. Government
                      agency, or corporate.
 
                      The three intermediate-term Portfolios -- the
                      INTERMEDIATE-TERM U.S. TREASURY PORTFOLIO, the GNMA
                      PORTFOLIO and the INTERMEDIATE-TERM CORPORATE PORTFOLIO
                      offer high credit quality, higher yields and a steadier
                      income than available from the three short-term
                      Portfolios. Price swings, however, can be substantial. The
                      choice between the three is again one of credit
                      quality -- U.S. Treasury, U.S. Government agency, or
                      corporate -- as well as one of prepayment risk (i.e.,
                      whether you are willing to take on the prepayment risk of
                      the GNMA Portfolio in exchange for generally higher
                      yields).
 
                      The two long-term Portfolios, the LONG-TERM U.S. TREASURY
                      PORTFOLIO and the LONG-TERM CORPORATE PORTFOLIO, are
                      designed for investors seeking higher credit quality and
                      steady levels of income, and who can withstand potentially
                      large fluctuations in the market value of their
                      investment. The choice between the two is one of credit
                      quality and call risk. The Long-Term Corporate Portfolio
                      generally offers higher yields than the Long-Term U.S.
                      Treasury Portfolio in exchange for higher credit and call
                      risks.
 
                      Finally, the HIGH YIELD CORPORATE PORTFOLIO is designed
                      for aggressive investors willing to take substantial risks
                      in pursuit of potentially higher rewards. Since the High
                      Yield Corporate Portfolio invests in securities that are
                      considered speculative by traditional investment
                      standards, an investment in the Portfolio should represent
                      only a limited portion of a balanced investment program
                      for most investors.
- --------------------------------------------------------------------------------
 
IMPLEMENTATION
OF POLICIES
EACH PORTFOLIO MAY
INVEST IN REPURCHASE
AGREEMENTS            Each Portfolio of the Fund utilizes a variety of
                      investment practices in pursuit of its objective.
 
                      Each Portfolio of the Fund may invest in repurchase
                      agreements according to the restrictions and limitations
                      set forth in "Investment Policies." A repurchase agreement
                      is a means of investing monies for a short period. In a
                      repurchase agreement, a seller -- a U.S. commercial bank
                      or recognized U.S. securities dealer -- sells securities
                      to a Portfolio and agrees to repurchase the securities at
                      the Portfolio's cost plus interest within a specified
                      period (normally one day). In these transactions, the
                      securities purchased by the Portfolio will have a total
                      value equal to or in excess of the value of the repurchase
                      agreement, and will be held by the Fund's Custodian bank
                      until repurchased.
 
                                       23
<PAGE>   70
 
                      The use of repurchase agreements involves certain risks.
                      For example, if the other party to the agreement defaults
                      on its obligation to repurchase the underlying security at
                      a time when the value of the security has declined, the
                      Portfolio may incur a loss upon disposition of the
                      security. If the other party to the agreement becomes
                      insolvent and subject to liquidation or reorganization
                      under the Bankruptcy Code or other laws, a court may
                      determine that the underlying security is collateral for a
                      loan by the Portfolio and not within the control of the
                      Portfolio. As a result, the Portfolio's ability to realize
                      on such collateral may be automatically stayed. Finally,
                      it is possible that the Portfolio may not be able to
                      substantiate its interest in the underlying security and
                      may be deemed an unsecured creditor of the other party to
                      the agreement. While each Portfolio's management
                      acknowledges these risks, it is expected that they can be
                      controlled through careful monitoring procedures.
 
EACH PORTFOLIO MAY
OWN RESTRICTED OR
ILLIQUID SECURITIES   Each Portfolio of the Fund may own restricted or illiquid
                      securities to a limited extent. Restricted or illiquid
                      securities are securities which are not freely marketable
                      or which are subject to restrictions upon sale under the
                      Securities Act of 1933. Each Portfolio may invest up to
                      15% of its net assets in restricted or illiquid
                      securities. The Fund's Board of Directors may from time to
                      time determine certain restricted securities known as Rule
                      144A securities to be liquid. Such securities will not be
                      subject to the 15% limitation described above.
 
FOUR PORTFOLIOS MAY
INVEST IN SECURITIES OF
FOREIGN ISSUERS       The Short-Term Corporate, Intermediate-Term Corporate,
                      Long-Term Corporate, and High Yield Corporate Portfolios
                      may hold securities of foreign issuers, but all such
                      securities must be denominated in U.S. dollars. Securities
                      of foreign issuers may trade in U.S. or foreign securities
                      markets. Securities of foreign issuers may involve
                      investment risks that are different from those of domestic
                      issuers. Such risks include the effect of foreign economic
                      policies and conditions, future political and economic
                      developments, and the possible imposition of exchange
                      controls or other foreign governmental restrictions on
                      foreign debt issuers. There may also be less publicly
                      available information about a foreign issuer than a
                      domestic issuer of securities. Foreign issuers are
                      generally not subject to the uniform accounting, auditing
                      and financial reporting standards that apply to domestic
                      issuers. Also, foreign debt markets may be characterized
                      by lower liquidity, greater price volatility, and higher
                      transaction costs. Additionally, it may be difficult to
                      obtain or enforce a legal judgment in a foreign court.
 
MOST PORTFOLIOS MAY
INVEST IN FUTURES
CONTRACTS, OPTIONS,
AND OTHER DERIVATIVE
SECURITIES            Each Portfolio of the Fund, except for the Short-Term
                      Federal Portfolio, may invest in futures contracts and
                      options to a limited extent. Specifically, a Portfolio may
                      enter into futures contracts provided that not more than
                      5% of its assets are required as a futures contract margin
                      deposit; in addition, a Portfolio may enter into futures
                      contracts and options transactions only to the extent that
                      obligations under such contracts or transactions represent
                      not more than 20% of the Portfolio's assets.
 
                      Futures contracts and options may be used for several
                      reasons: to maintain cash reserves while simulating full
                      investment, to facilitate trading, to reduce transaction
                      costs, or to seek higher investment returns when a
                      specific futures contract is priced more attractively than
                      other futures contracts or the underlying security or
 
                                       24
<PAGE>   71
 
                      index. The Portfolios intend to use futures contracts only
                      for bona fide hedging purposes and will not use futures
                      contracts or options for speculative purposes.
 
FUTURES CONTRACTS
AND OPTIONS POSE
CERTAIN RISKS         The primary risks associated with the use of futures
                      contracts and options are: (i) imperfect correlation
                      between the change in market value of the bonds held by a
                      Portfolio and the prices of futures contracts and options;
                      and (ii) possible lack of a liquid secondary market for a
                      futures contract and the resulting inability to close a
                      futures position prior to its maturity date. The risk of
                      imperfect correlation will be minimized by investing only
                      in those contracts whose price fluctuations are expected
                      to resemble those of the Portfolio's underlying
                      securities. The risk that a Portfolio will be unable to
                      close out a futures position will be minimized by entering
                      into such transactions on a national exchange with an
                      active and liquid secondary market.
 
                      The risk of loss in trading futures contracts in some
                      strategies can be substantial, due both to the low margin
                      deposits required and the extremely high degree of
                      leverage involved in futures pricing. As a result, a
                      relatively small price movement in a futures contract may
                      result in immediate and substantial loss (or gain) to the
                      investor. When investing in futures contracts, a Portfolio
                      will segregate cash or other liquid portfolio securities
                      in the amount of the underlying obligation.
 
DERIVATIVE
INVESTING             Derivatives are instruments whose value is linked to or
                      derived from an underlying security or index. The most
                      common are futures and options which are described above.
                      Other derivatives include swaps, inverse floaters, IO's
                      (interest only), and PO's (principal only). Derivatives
                      may be traded separately on exchanges or in the
                      over-the-counter market, or they may be imbedded in other
                      securities. The most common imbedded derivative is the
                      call option attached to or imbedded in a callable
                      government or callable corporate bond. The owner of a
                      traditional callable bond holds a combination of a long
                      position in a non-callable bond and a short position in a
                      call option on that bond, i.e. the bond issuer has the
                      right to call the bond away from the holder of the bond.
                      Any of these instruments may also be used individually or
                      in combination to hedge against unfavorable changes in
                      interest rates, or to speculate on anticipated changes in
                      interest rates. Derivatives may be structured with no or a
                      high degree of leverage. When derivatives are used as
                      hedges, the risk incurred is that the derivative
                      instrument's value may change differently than the value
                      of the security being hedged. This "basis risk" is
                      generally lower than the risk associated with an unhedged
                      position in the security being hedged. Some derivatives
                      may entail liquidity risk, i.e. the risk that the
                      instrument cannot be sold at a reasonable price in highly
                      volatile markets. Leveraged derivatives used for
                      speculation are very volatile, and therefore, very risky.
                      However, the Fund's Portfolios will only utilize
                      derivatives for hedging or arbitrage purposes, and not for
                      speculative purposes. Over-the-counter derivatives involve
                      a counterparty risk, i.e. the risk that the individual or
                      institution on the other side of the agreement will not or
                      cannot meet its obligations under the derivative
                      agreement.
 
EACH PORTFOLIO MAY
LEND ITS SECURITIES   Each Portfolio of the Fund may lend its investment
                      securities to qualified institutional investors for either
                      short-term or long-term purposes of realizing additional
                      income. Loans of securities by a Portfolio will be
                      collateralized by cash, letters of credit, or securities
                      issued or guaranteed by the U.S. Government or its
                      agencies. The collateral
 
                                       25
<PAGE>   72
 
                      will equal at least 100% of the current market value of
                      the loaned securities, and such loans may not exceed
                      33 1/3% of the value of the Portfolio's total assets
                      (including any collateral obtained in connection with such
                      loans).
 
   
MOST PORTFOLIOS MAY
INVEST IN CMOS        The Short-Term Federal, Short- and Intermediate-Term
                      Corporate and the Short-, Intermediate- and Long-Term U.S.
                      Treasury Portfolios may invest in collateralized mortgage
                      obligations (CMOs), bonds that are collateralized by whole
                      loan mortgages or mortgage pass-through securities. In the
                      case of the Short-Term Federal and the Short-,
                      Intermediate- and Long-Term U.S. Treasury Portfolios, only
                      CMOs issued by agencies or instrumentalities of the U.S.
                      Government will be purchased. However, the Short-,
                      Intermediate- and Long-Term Corporate Portfolios may also
                      purchase privately-issued CMOs carrying investment grade
                      ratings. The bonds issued under a CMO structure are
                      divided into groups with varying maturities, and the cash
                      flows generated by the mortgages or mortgage pass-through
                      securities in the collateral pool are used to first pay
                      interest and then pay principal to the CMO bondholders.
                      Under the CMO structure, the repayment of principal among
                      the different groups is prioritized in accordance with the
                      terms of the particular CMO issuance. The "fastest-pay"
                      group of bonds, as specified in the prospectus for the
                      issuance, would initially receive all principal payments.
                      When that group of bonds is retired, the next group or
                      groups, in the sequence, as specified in the prospectus,
                      receive all of the principal payments until all of the
                      groups are retired. Aside from market risk, the primary
                      risk involved in any mortgage security, such as a CMO
                      issuance, is its exposure to prepayment risk. To the
                      extent a particular group of bonds is exposed to this
                      risk, the bondholder is generally compensated in the form
                      of higher yield (see "Investment Risks"). In order to
                      provide security, in addition to the underlying
                      collateral, many CMO issues also include minimum
                      reinvestment rate and minimum sinking-fund guarantees.
                      Typically, the Portfolios will invest in those CMOs that
                      most appropriately reflect their average maturities and
                      market risk profiles. Consequently, the Short-Term
                      Portfolios invest only in CMOs with highly predictable
                      short-term average maturities. Similarly, the
                      Intermediate-Term Portfolios will invest in those CMOs
                      that carry market risks and expected average maturities
                      consistent with intermediate-term bonds, and the Long-Term
                      U.S. Treasury Portfolio will invest in those CMOs that
                      carry market risks and expected average maturities
                      consistent with long-term bonds.
    
 
                      The maturity of some classes of CMOs may be very difficult
                      to predict because any such predictions are highly
                      dependent upon assumptions regarding the prepayments which
                      CMOs may experience. Deviations in the actual prepayments
                      experienced may significantly affect the ultimate maturity
                      of CMOs, and in such an event, the maturity and risk
                      characteristics of CMOs purchased by the Portfolios may be
                      significantly greater or less than intended. The
                      possibility that rising interest rates may cause
                      prepayments to occur at a slower than expected rate is
                      known as extension risk. This particular risk may
                      effectively change a CMO which was considered short- or
                      intermediate-term at the time of purchase into a long-term
                      security. Alternatively, there are certain classes of CMOs
                      that are by design constructed to have highly predictable
                      average maturities. Such CMOs will retain their relative
                      predictability over a broad range of prepayment
                      experience. The
 
                                       26
<PAGE>   73
 
                      Portfolios expect to control extension risk by purchasing
                      these specific classes of CMOs which, in the advisers'
                      opinions, are reasonably predictable.
 
THE GNMA PORTFOLIO
MAY INVEST IN REMICS  The GNMA Portfolio may invest in real estate investment
                      conduits ("REMICs"). A REMIC is a CMO that qualifies for
                      special tax treatment under the Internal Revenue Code and
                      invests in certain mortgages principally secured by
                      interests in real property. Investors may purchase
                      beneficial interests in REMICs, which are known as
                      "regular" interests, or "residual" interests. Guaranteed
                      REMIC pass-through certificates ("REMIC Certificates")
                      issued by FNMA or FHLMC represent beneficial ownership
                      interests in a REMIC trust consisting principally of
                      mortgage loans or FNMA, FHLMC or GNMA-guaranteed mortgage
                      pass-through certificates. For FHLMC REMIC Certificates,
                      FHLMC guarantees the timely payment of interest, and also
                      guarantees the payment of principal as payments are
                      required to be made on the underlying mortgage
                      participation certificates. FNMA REMIC Certificates are
                      issued and guaranteed as to timely distribution of
                      principal and interest by FNMA.
 
FIVE PORTFOLIOS MAY
INVEST IN ASSET-BACKED
SECURITIES            The Short-Term Federal, Short-Term Corporate,
                      Intermediate-Term Corporate, Long-Term Corporate and High
                      Yield Corporate Portfolios of the Fund may invest in
                      asset-backed securities. These securities represent
                      partial ownership in pools of consumer or commercial
                      loans--such as mortgage or automobile loans, credit card
                      balances, equipment lease loans, and collateralized bond
                      obligations (bonds backed by other securities).
 
                      Besides being backed by the loans or other assets in the
                      pool, many of these securities come with credit
                      enhancements as additional protection against default.
                      Such credit enhancements could include
                      over-collateralization or insurance coverage provided by a
                      highly rated (usually AAA) institution other than the
                      security's issuer.
 
                      The value of asset-backed securities ultimately depends on
                      whether the borrowers repay the underlying loans, and
                      whether the credit enhancements, if any, are adequate.
                      Despite any credit enhancements, the value of an
                      asset-backed security may fluctuate because of several
                      factors, including:
 
                      - The market's perception of the value of the assets
                        backing the security.
 
                      - The creditworthiness of the agent in charge of
                        collecting loan payments and passing them through to
                        security holders, the firm that originated the loans,
                        and the institution providing any credit insurance or
                        guarantees.
 
                      - The nature of any insurance or other credit
                        enhancements.
 
                      Another risk of asset-backed securities, especially in
                      periods of declining interest rates, is that borrowers may
                      prepay the underlying loans. These prepayments shorten the
                      weighted average life of an asset-backed security and may
                      lower its return.
 
PORTFOLIO TURNOVER
RATES WILL VARY       Although they generally seek to invest for the long term,
                      the Portfolios of the Fund retain the right to sell
                      securities regardless of how long they have been held. It
                      is anticipated that the annual portfolio turnover rate for
                      the GNMA, Long-Term Corporate and High Yield Corporate
                      Portfolios will not exceed 100%. A 100% turnover rate
                      would occur, for example, if all of the securities in a
                      Portfolio were replaced
 
                                       27
<PAGE>   74
 
                      within one year. For the Intermediate-Term and Long-Term
                      U.S. Treasury and the Intermediate-Term Corporate
                      Portfolios, portfolio turnover rates will generally not
                      exceed 200%. For the Short-Term U.S. Treasury, Short-Term
                      Federal, and Short-Term Corporate Portfolios, portfolio
                      turnover rates will be higher due to the short-term
                      maturities of the securities purchased, but are not
                      expected to exceed 300%. A higher portfolio turnover rate
                      will cause a Portfolio to incur additional brokerage costs
                      and may cause a Portfolio to realize a higher level of
                      capital gains or losses.
- --------------------------------------------------------------------------------
 
INVESTMENT
LIMITATIONS
THE FUND HAS ADOPTED
CERTAIN FUNDAMENTAL
LIMITATIONS           Each of the Fund's Portfolios has adopted limitations on
                      some of its investment policies. Some of these limitations
                      are that a Portfolio will not:
 
                      (a) with respect to 75% of its assets, invest more than 5%
                          of the value of its assets in the securities of any
                          single company or purchase more than 10% of the voting
                          securities of any issuer (except for securities issued
                          or guaranteed by the U.S. Government or any of its
                          agencies or instrumentalities);
 
                      (b) invest more than 5% of its assets in the securities of
                          companies that have a continuous operating history of
                          less than three years;
 
                      (c) invest more than 25% of its assets in any one
                          industry, provided that: (i) this limitation does not
                          apply to obligations issued or guaranteed by the U.S.
                          Government or its agencies or instrumentalities; (ii)
                          utility companies will be divided according to their
                          services (for example, gas, gas transmission,
                          electric, electric and gas, and telephone will each be
                          considered a separate industry); and (iii) financial
                          service companies will be classified according to the
                          end users of their services (for example, automobile
                          finance, bank finance, and diversified finance will be
                          considered as separate industries);
 
                      (d) borrow money, except that the Portfolio may borrow
                          from banks (or through reverse repurchase agreements),
                          for temporary or emergency (not leveraging) purposes,
                          including the meeting of redemption requests which
                          might otherwise require the untimely disposition of
                          securities, in an amount not exceeding 15% of the
                          value of the Portfolio's net assets (including the
                          amount borrowed and the value of any outstanding
                          reverse repurchase agreements) at the time the
                          borrowing is made. Whenever borrowings exceed 5% of
                          the value of the Portfolio's net assets, the Portfolio
                          will not make any additional investments; and
 
                      (e ) pledge, mortgage or hypothecate its assets to an
                           extent greater than 5% of the value of its total
                           assets.
 
                      A complete list of the Fund's investment limitations can
                      be found in the Statement of Additional Information. These
                      limitations are fundamental and may be changed only by
                      approval of a majority of the Fund's shareholders.
- --------------------------------------------------------------------------------
 
MANAGEMENT
OF THE FUND
VANGUARD ADMINISTERS
AND DISTRIBUTES THE
FUND                  The Fund is a member of The Vanguard Group of Investment
                      Companies, a family of more than 30 investment companies
                      with more than 95 distinct portfolios and total assets in
                      excess of $370 billion. Through their jointly-owned
                      subsidiary, The Vanguard Group, Inc. ("Vanguard"), the
                      Fund and the other funds in the Group obtain at cost
                      virtually all of their corporate management,
                      administrative, shareholder
 
                                       28
<PAGE>   75
 
                      accounting and distribution services. Vanguard also
                      provides investment advisory services on an at-cost basis
                      to certain Vanguard funds. As a result of Vanguard's
                      unique corporate structure, the Vanguard funds have costs
                      substantially lower than those of most competing mutual
                      funds. In 1997, the average expense ratio (annual costs
                      including advisory fees divided by total net assets) for
                      the Vanguard funds amounted to approximately 0.28%
                      compared to an average of 1.24% for the mutual fund
                      industry (data provided by Lipper Analytical Services).
 
                      The Officers of the Fund oversee its day-to-day operations
                      and are responsible to the Fund's Board of Directors. The
                      Directors set broad policies for the Fund and choose its
                      Officers. A list of the Directors and Officers of the Fund
                      and a statement of their present positions and principal
                      occupations during the past five years can be found in the
                      Statement of Additional Information.
 
                      Vanguard employs a supporting staff of management and
                      administrative personnel needed to provide the requisite
                      services to the funds and also furnishes the funds with
                      necessary office space, furnishings and equipment. Each
                      fund pays its share of Vanguard's net expenses, which are
                      allocated among the funds under methods approved by the
                      Board of Directors (Trustees) of each fund. In addition,
                      each fund bears its own direct expenses, such as legal,
                      auditing and custodian fees.
 
                      Vanguard also provides distribution and marketing services
                      to the Vanguard funds. The funds are available on a
                      no-load basis (i.e., there are no sales commissions or
                      12b-1 fees). However, each fund bears its share of the
                      Group's distribution costs.
- --------------------------------------------------------------------------------
 
INVESTMENT
ADVISERS
THE FUND HAS TWO
INVESTMENT ADVISERS   The Fund utilizes two investment advisers. Wellington
                      Management Company, LLP serves as investment adviser to
                      the GNMA, Long-Term Corporate and High Yield Corporate
                      Portfolios; Vanguard's Fixed Income Group serves as
                      investment adviser to the remaining Portfolios.
 
WELLINGTON
MANAGEMENT
COMPANY, LLP          Under an investment advisory agreement with the Fund dated
                      May 1, 1996, Wellington Management Company, LLP ("WMC"),
                      75 State Street, Boston, MA 02109, manages the investment
                      and reinvestment of assets in the GNMA, Long-Term
                      Corporate, and High Yield Corporate Portfolios, and
                      continuously reviews, supervises and administers the
                      investment program of these three Portfolios. WMC
                      discharges its responsibilities subject to the control of
                      the Officers and Directors of the Fund.
 
   
                      WMC is a professional investment counseling firm which
                      globally provides investment services to investment
                      companies, institutions and individuals. Among the clients
                      of WMC are more than 10 of the investment companies of The
                      Vanguard Group. As of January 31, 1998, WMC held
                      discretionary management authority with respect to more
                      than $177 billion of assets. WMC and its predecessor
                      organizations have provided investment advisory services
                      to investment companies since 1928 and to investment
                      counseling clients since 1960.
    
 
                      Paul D. Kaplan, Senior Vice President of WMC, serves as
                      the portfolio manager for the GNMA Portfolio. Prior to his
                      appointment in 1994, Mr. Kaplan was assistant portfolio
                      manager for the GNMA Portfolio. Mr. Kaplan has been
                      associated with
 
                                       29
<PAGE>   76
 
                      WMC for 20 years and also currently manages the bond
                      components of Vanguard/Wellington Fund and the Balanced
                      Portfolio of the Vanguard Variable Insurance Fund.
 
   
                      Earl E. McEvoy, Senior Vice President of WMC, serves as
                      the portfolio manager of the Fund's Long-Term Corporate
                      Portfolio, a position he has held since 1994. Mr. McEvoy
                      also manages the Fund's High Yield Corporate Portfolio, as
                      well as Vanguard Preferred Stock Fund, the High Yield Bond
                      Portfolio of the Vanguard Variable Insurance Fund and the
                      bond components of the Utilities Income Portfolio of
                      Vanguard Specialized Portfolios and Vanguard/Wellesley
                      Income Fund. Mr. McEvoy has been associated with WMC for
                      20 years.
    
 
                      Mr. Kaplan and Mr. McEvoy are supported by research and
                      other investment services provided by the professional
                      staff of WMC.
 
                      Under the Fund's investment advisory agreement, the fee
                      paid to WMC is based on the total assets of the GNMA
                      Portfolio, the Long-Term Corporate Portfolio and the High
                      Yield Corporate Portfolio of Vanguard Fixed Income
                      Securities Fund. The three Portfolios pay WMC an aggregate
                      fee at the end of each fiscal quarter, calculated by
                      applying a quarterly rate based on the following annual
                      percentage rates, to the average month-end net assets of
                      each Portfolio for the quarter. Separate fee schedules
                      apply to each Portfolio.
 
                                            GNMA PORTFOLIO
 
<TABLE>
<CAPTION>
                                            NET ASSETS               RATE
                               ------------------------------------  -----
                               <S>                                   <C>
                               First $3 billion                      .020%
                               Next $3 billion                       .010%
                               Over $6 billion                       .008%
</TABLE>
 
                                    LONG-TERM CORPORATE PORTFOLIO
 
<TABLE>
<CAPTION>
                                            NET ASSETS               RATE
                               ------------------------------------  -----
                               <S>                                   <C>
                               First $1 billion                      .040%
                               Next $1 billion                       .030%
                               Next $1 billion                       .020%
                               Over $3 billion                       .015%
</TABLE>
 
                                    HIGH YIELD CORPORATE PORTFOLIO
 
<TABLE>
<CAPTION>
                                            NET ASSETS               RATE
                               ------------------------------------  -----
                               <S>                                   <C>
                               First $1 billion                      .060%
                               Next $1 billion                       .040%
                               Next $1 billion                       .030%
                               Over $3 billion                       .025%
</TABLE>
 
                      The advisory fee, as determined above, shall be allocated
                      to each Portfolio based on the net assets of each. For the
                      fiscal year ended January 31, 1998, the GNMA, Long-Term
                      Corporate and High Yield Corporate Portfolios paid annual
                      advisory fees to WMC equal to, respectively, .01 of 1%,
                      .03 of 1%, and .04 of 1% of average net assets.
 
VANGUARD FIXED
INCOME GROUP          The Short-Term U.S. Treasury, Short-Term Federal, Short-
                      and Intermediate-Term Corporate, and Intermediate-Term and
                      Long-Term U.S. Treasury Portfolios receive
 
                                       30
<PAGE>   77
 
                      all investment advisory services on an at-cost basis from
                      Vanguard's Fixed Income Group. The Group provides
                      investment advisory services to more than 40 Vanguard
                      money market and bond portfolios, both taxable and
                      tax-exempt. Total assets under management by Vanguard's
                      Fixed Income Group were more than $100 billion as of
                      January 31, 1998.
 
                      Ian A. MacKinnon, Managing Director of Vanguard, has been
                      in charge of the Fixed Income Group since its inception in
                      1981. Mr. MacKinnon is responsible for setting the broad
                      investment strategies employed by the Fund, and for
                      overseeing the portfolio managers who implement those
                      strategies on a day-to-day basis. The Fund's portfolio
                      managers are as follows:
 
   
                      - Robert F. Auwaerter, a Principal of Vanguard, serves as
                        portfolio manager of the Long-Term U.S. Treasury,
                        Short-Term Corporate, Intermediate-Term U.S. Treasury,
                        and Intermediate-Term Corporate Portfolios. Associated
                        with the Fixed Income Group since 1981, Mr. Auwaerter
                        has managed the Short-Term Corporate Portfolio since
                        1983, the Long-Term U.S. Treasury Portfolio since 1994,
                        and each of the other two Portfolios since their
                        respective inceptions. (Previously, the Long-Term U.S.
                        Treasury Portfolio was managed by Anthony Jiorle.)
    
 
                      - John Hollyer, a Principal of Vanguard, serves as
                        portfolio manager of the Short-Term U.S. Treasury
                        Portfolio and the Short-Term Federal Portfolio
                        (previously, the Portfolios were managed by Robert
                        Auwaerter). Associated with the Fixed Income Group since
                        1989, Mr. Hollyer began managing the Short-Term Federal
                        Portfolio in 1996 and the Short-Term U.S. Treasury
                        Portfolio in 1998.
 
   
                      The Fixed Income Group manages the investment and
                      reinvestment of the assets of these six Portfolios and
                      continuously reviews, supervises and administers each
                      Portfolio's investment program, subject to the maturity
                      and quality standards specified in this Prospectus and
                      supplemental guidelines approved by the Fund's Board of
                      Directors. The Fixed Income Group's selection of
                      investments for the Portfolios is based on: (a) continuing
                      credit analysis of those instruments held in the
                      Portfolios and those being considered for inclusion
                      therein; (b) possible disparities in yield relationships
                      between different money market instruments; and (c) actual
                      or anticipated movements in the general level of interest
                      rates.
    
 
                      Vanguard's Fixed Income Group is also responsible for the
                      placement of portfolio transactions and the negotiation of
                      commissions for the six Portfolios. The purchase and sale
                      of investment securities will ordinarily be principal
                      transactions. Portfolio securities will normally be
                      purchased directly from the issuer or from an underwriter
                      or market maker for the securities. There usually will be
                      no brokerage commissions paid by a Portfolio for
                      securities purchased from an issuer. Purchases from
                      underwriters of securities will include a commission or
                      concession paid by the issuer to the underwriter, and
                      purchases from dealers serving as market makers will
                      include a dealer's mark-up.
 
PORTFOLIO TRANSACTIONS The advisers are authorized to choose brokers or dealers
                      to handle the purchase and sale of the Fund's securities,
                      and are directed to get the best available price and most
 
                                       31
<PAGE>   78
 
                      favorable execution from these brokers with respect to all
                      transactions. At times, the advisers may choose brokers
                      who charge higher commissions in the interests of
                      obtaining better execution of a transaction. If more than
                      one broker can obtain the best available price and
                      favorable execution of a transaction, then the advisers
                      are authorized to choose a broker who, in addition to
                      executing the transaction, will provide research services
                      to the advisers or the Fund. However, the adviser will not
                      pay higher commissions specifically for the purpose of
                      obtaining research services. The Fund may direct the
                      advisers to use a particular broker for certain
                      transactions in exchange for commission rebates or
                      research services provided to the Fund.
 
                      Vanguard's Fixed Income Group may occasionally make
                      recommendations to other Vanguard Funds or clients which
                      result in their purchasing or selling securities
                      simultaneously with a Portfolio of the Fund. As a result,
                      the demand for securities being purchased or the supply of
                      securities being sold may increase, and this could have an
                      adverse effect on the price of those securities. It is the
                      policy of the Fixed Income Group not to favor one client
                      over another in making recommendations or placing an
                      order. If two or more clients are purchasing a given
                      security on the same day from the same broker/dealer, such
                      transactions may be averaged as to price.
- --------------------------------------------------------------------------------
 
DIVIDENDS,
CAPITAL GAINS
AND TAXES
DIVIDENDS ARE PAID ON
THE FIRST BUSINESS DAY
OF EACH MONTH         Dividends consisting of virtually all of the ordinary
                      income of each Portfolio of the Fund are declared daily
                      and are payable to shareholders of record at the time of
                      declaration. Such dividends are paid on the first business
                      day of each month. Net capital gains distributions, if
                      any, will be made annually. Each Portfolio's dividends and
                      capital gains distributions are automatically reinvested
                      in additional shares. The Fund is managed without regard
                      to tax ramifications.
 
   
                      Each Portfolio of the Fund intends to continue to qualify
                      for taxation as a "regulated investment company" under the
                      Internal Revenue Code so that none of the Portfolios will
                      be subject to federal income tax to the extent its income
                      is distributed to shareholders.
    
 
                      If you utilize the Fund as an investment option in an
                      employer-sponsored retirement or savings plan, dividend
                      distributions from the Fund will generally not be subject
                      to current taxation, but will accumulate on a tax-deferred
                      basis. In general, employer-sponsored retirement and
                      savings plans are governed by complex tax rules. If you
                      participate in such a plan, consult your plan
                      administrator, your plan's Summary Plan Description, or a
                      professional tax adviser regarding the tax consequences of
                      your participation in the plan and of any plan
                      contributions or withdrawals.
- --------------------------------------------------------------------------------
 
THE SHARE
PRICE OF EACH
PORTFOLIO             Each Portfolio's share price, or "net asset value" per
                      share, is calculated by dividing the total assets of the
                      Portfolio, less all liabilities, by the total number of
                      shares outstanding, except for the Short-Term Corporate
                      Portfolio whereby net asset value is calculated by
                      dividing the net assets attributed to each share class, by
                      the total number of shares outstanding for that share
                      class. The net asset value is determined as of the close
                      of the New York Stock Exchange (generally 4:00 p.m.
                      Eastern time) on each day that the Exchange is open for
                      trading.
 
                                       32
<PAGE>   79
 
                      Short-term instruments (those acquired with remaining
                      maturities of 60 days or less) may be valued at cost, plus
                      or minus any amortized discount or premium, which
                      approximates market value.
 
                      Bonds and other fixed income securities may be valued on
                      the basis of prices provided by a pricing service when
                      such prices are believed to reflect the fair market value
                      of such securities. The prices provided by a pricing
                      service may be determined without regard to bid or last
                      sale prices of each security, but take into account
                      institutional-size transactions in similar groups of
                      securities as well as any developments related to specific
                      securities.
 
                      Other assets and securities for which no quotations are
                      readily available or which are restricted as to sale (or
                      resale) are valued by such methods as the Board of
                      Directors deems in good faith to reflect fair value.
 
                      The share price for each Portfolio can be found daily in
                      the mutual fund listings of most major newspapers under
                      the heading of Vanguard Funds.
- --------------------------------------------------------------------------------
 
   
GENERAL
INFORMATION           The Fund is a Maryland corporation. The Articles of
                      Incorporation permit the Directors to issue 4,550,000,000
                      shares of common stock, with a $.001 par value. The Board
                      of Directors has the power to designate one or more series
                      ("Portfolios") of shares of common stock and to classify
                      or reclassify any unissued shares with respect to such
                      series. Currently the Fund is offering shares of nine
                      Portfolios.
    
 
                      The shares of each Portfolio are fully paid and
                      non-assessable; have no preference as to conversion,
                      exchange, dividends, retirement or other features; and
                      have no pre-emptive rights. Such shares have
                      non-cumulative voting rights, meaning that the holders of
                      more than 50% of the shares voting for the election of
                      Directors can elect 100% of the Directors if they so
                      choose.
 
                      Annual meetings of shareholders will not be held except as
                      required by the Investment Company Act of 1940 and other
                      applicable law. An annual meeting will be held to vote on
                      the removal of a Director or Directors of the Fund if
                      requested in writing by the holders of not less than 10%
                      of the outstanding shares of the Fund.
 
                      All securities and cash for the GNMA, Long-Term Corporate
                      and High Yield Corporate Portfolios are held by Chase
                      Manhattan Bank, New York, NY. For the Short-Term Federal,
                      Short-Term Corporate, and Long-Term U.S. Treasury
                      Portfolios, all securities and cash are held by CoreStates
                      Bank, N.A., Philadelphia, PA. For the Short-Term and
                      Intermediate-Term U.S. Treasury and the Intermediate-Term
                      Corporate Portfolios, all securities and cash are held by
                      State Street Bank and Trust Company, Boston, MA.
                      CoreStates Bank, N.A., Philadelphia, PA, holds daily cash
                      balances that are used by the Fund's Portfolios to invest
                      in repurchase agreements or securities acquired in these
                      transactions. The Vanguard Group, Inc., Valley Forge, PA,
                      serves as the Fund's Transfer and Dividend Disbursing
                      Agent. Price Waterhouse LLP serves as independent
                      accountants for the Fund and will audit its financial
                      statements annually. The Fund is not involved in any
                      litigation.
- --------------------------------------------------------------------------------
 
                                       33
<PAGE>   80
 
                                 SERVICE GUIDE
 
PARTICIPATING IN
YOUR PLAN             One or more of the Portfolios of the Fund is available as
                      an investment option in your retirement or savings plan.
                      The administrator of your plan or your employee benefits
                      office can provide you with detailed information on how to
                      participate in your plan and how to elect a Portfolio of
                      the Fund as an investment option.
 
                      If you have any questions about a Portfolio, including the
                      Portfolio's investment objective, policies, risk
                      characteristics or historical performance, please contact
                      Vanguard's Participant Services (1-800-523-1188). Please
                      have your Social Security number available when you call.
 
                      If you have questions about your account, contact your
                      plan administrator or the organization which provides
                      recordkeeping services for your plan.
- --------------------------------------------------------------------------------
INVESTMENT OPTIONS
AND ALLOCATIONS       You may be permitted to elect different investment
                      options, alter the amounts contributed to your plan, or
                      change how contributions are allocated among your
                      investment options in accordance with your plan's specific
                      provisions. See your plan administrator or employee
                      benefits office for more details.
- --------------------------------------------------------------------------------
TRANSACTIONS IN FUND
SHARES                Contributions, exchanges or redemptions of a Portfolio's
                      shares are effective when received in "good order" by
                      Vanguard. "Good order" means that complete information on
                      the purchase, exchange or redemption and the appropriate
                      monies have been received by Vanguard.
 
                      Vanguard must consider the interests of all Portfolio
                      shareholders. Therefore, for institutional investors who
                      are not participants in a retirement or savings plan, we
                      reserve the right to:
 
                      - Delay or reject any purchase or exchange request that
                        may disrupt the Portfolio's operation or performance.
 
                      - Revise or terminate the exchange privilege or limit the
                        amount of an exchange, at any time, without notice.
 
                      - Take up to seven days to deliver your redemption
                        proceeds.
 
                      - Pay redemption proceeds -- in whole or in
                        part -- through a distribution in kind of readily
                        marketable securities.
- --------------------------------------------------------------------------------
MAKING EXCHANGES      The exchange privilege (your ability to redeem shares from
                      one fund to purchase shares of another fund) may be
                      available to you through your plan. Although we make every
                      effort to maintain the exchange privilege, Vanguard
                      reserves the right to revise or terminate the exchange
                      privilege, limit the amount of an exchange, or reject any
                      exchange, at any time, without notice. Because excessive
                      exchanges can potentially disrupt the management of a Fund
                      and increase its transaction costs, Vanguard limits
                      exchange activity to TWO SUBSTANTIVE EXCHANGE REDEMPTIONS
                      (at least 30 days apart) from any Fund during any 12-month
                      period. "Substantive" means either a dollar amount or a
                      series of movements between Vanguard funds that Vanguard
                      determines, in its sole discretion, could have an adverse
                      impact on
 
                                       34
<PAGE>   81
 
                      the management of the Fund. In addition, certain
                      investment options, particularly funds made up of company
                      stock or investment contracts, may be subject to unique
                      restrictions. Contact your plan administrator for details
                      on the exchange policies that apply to your plan.
 
                      Before making an exchange, you should consider the
                      following:
 
                      - If you are making an exchange to another Vanguard Fund
                        option, please read the Fund's prospectus. Contact
                        Participant Services (1-800-523-1188) for a copy.
 
                      - Exchanges are accepted by Vanguard only as permitted by
                        your plan. Your plan administrator can explain how
                        frequently exchanges are allowed.
- --------------------------------------------------------------------------------
 
                                       35
<PAGE>   82
 
                     [THIS PAGE INTENTIONALLY LEFT BLANK.]
<PAGE>   83
 
- --------------------------------------------------------------------------------
 
<TABLE>
<S>       <C>                             <C>
          [Vanguard Logo]
          ---------------------------
          THE VANGUARD GROUP
          P.O. Box 2900
          Valley Forge, PA 19482
          INSTITUTIONAL PARTICIPANT
          SERVICES DEPARTMENT:
          1-800-523-1188
          TRANSFER AGENT:
          The Vanguard Group, Inc.
          P.O. Box 2900
          Valley Forge, PA 19482
          I028
 
<CAPTION>
<S>        <C>
                                   [Flag Logo]
                                 [Vanguard Logo]
                      I  N  S  T  I  T  U  T  I  O  N  A  L
                          P  R  O  S  P  E  C  T  U  S
                                  MAY 29, 1998
                              [VANGUARD GROUP LOGO]
</TABLE>
 
- --------------------------------------------------------------------------------
<PAGE>   84
 
================================================================================
 
LOGO
                                                  A Member of The Vanguard Group
================================================================================
 
PROSPECTUS -- MAY 29, 1998
- --------------------------------------------------------------------------------
 
NEW ACCOUNT INFORMATION: INVESTOR INFORMATION DEPARTMENT -- 1-800-662-7447
(SHIP)
- --------------------------------------------------------------------------------
 
SHAREHOLDER ACCOUNT SERVICES: CLIENT SERVICES DEPARTMENT -- 1-800-662-2739
(CREW)
- --------------------------------------------------------------------------------
 
INVESTMENT
OBJECTIVE AND
POLICIES              Vanguard Fixed Income Securities Fund, Inc. (the "Fund")
                      is an open-end diversified investment company which
                      consists of nine Portfolios. This prospectus relates only
                      to the High Yield Corporate Portfolio (the "Portfolio").
                      The objective of the Portfolio is to provide investors
                      with a high level of current income. A MAJORITY OF THE
                      ASSETS OF THE HIGH YIELD CORPORATE PORTFOLIO MAY BE RATED
                      BA OR B. SECURITIES WITH SUCH RATINGS ARE COMMONLY
                      REFERRED TO AS "JUNK BONDS" AND ARE CONSIDERED SPECULATIVE
                      BY THE MAJOR RATINGS AGENCIES. INVESTORS SHOULD CAREFULLY
                      ASSESS THE RISKS ASSOCIATED WITH AN INVESTMENT IN THIS
                      PORTFOLIO BEFORE PURCHASING SHARES. There is no assurance
                      that the Portfolio will achieve its stated objective.
                      Shares of the Fund are neither insured nor guaranteed by
                      any agency of the U.S. Government, including the FDIC.
- --------------------------------------------------------------------------------
 
OPENING AN
ACCOUNT               To open a regular (non-retirement) account, please
                      complete and return the Account Registration Form. If you
                      need assistance in completing this Form, please call the
                      Investor Information Department. To open an Individual
                      Retirement Account (IRA), please use a Vanguard IRA
                      Adoption Agreement. To obtain a copy of this form, call
                      1-800-662-7447, Monday through Friday, from 8:00 a.m. to
                      9:00 p.m. and Saturday from 9:00 a.m. to 4:00 p.m.
                      (Eastern time). The minimum initial investment is $3,000
                      or $1,000 for Uniform Gifts/Transfers to Minors Act
                      accounts. The Portfolio is offered on a no-load basis
                      (i.e., there are no sales commissions or 12b-1 fees).
                      However, the Portfolio incurs expenses for investment
                      advisory, management, administrative and distribution
                      services. If shares of this Portfolio are redeemed or
                      exchanged prior to being held for one year they will be
                      subject to a 1% redemption fee. See "Fund Expenses".
- --------------------------------------------------------------------------------
 
ABOUT THIS
PROSPECTUS            This Prospectus is designed to set forth concisely the
                      information you should know about the Portfolio before you
                      invest. It should be retained for future reference. A
                      "Statement of Additional Information" containing
                      additional information about the Portfolio has been filed
                      with the Securities and Exchange Commission. This
                      Statement is dated May 29, 1998 and has been incorporated
                      by reference into this Prospectus. A copy may be obtained
                      without charge by writing to the Portfolio, calling the
                      Investor Information Department at 1-800-662-7447, or
                      visiting the Securities and Exchange Commission's website
                      (www.sec.gov).
- --------------------------------------------------------------------------------
 
TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                Page                                          Page                                          Page
<S>                            <C>         <C>                               <C>         <C>                               <C>
Portfolio Expenses............   2         Investment Limitations...........   12                   SHAREHOLDER GUIDE
Financial Highlights..........   3         Management of the Portfolio......   12        Opening an Account and
Yield and Total Return........   3         Investment Adviser...............   13        Purchasing Shares................   17
          FUND INFORMATION                 Dividends, Capital Gains                      When Your Account Will
Investment Objective..........   4         and Taxes........................   14        Be Credited......................   20
Investment Policies...........   4         The Share Price of                            Selling Your Shares..............   21
Investment Risks..............   6         the Portfolio....................   15        Exchanging Your Shares...........   23
Who Should Invest.............   8         General Information..............   16        Important Information About
Implementation of Policies....   9                                                       Telephone Transactions...........   25
                                                                                         Transferring Registration........   26
                                                                                         Other Vanguard Services..........   26
</TABLE>
 
- --------------------------------------------------------------------------------
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION, NOR HAS THE SECURITIES AND EXCHANGE COMMISSION PASSED UPON
THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY
IS A CRIMINAL OFFENSE.
- --------------------------------------------------------------------------------
<PAGE>   85
 
PORTFOLIO
EXPENSES              The following table illustrates ALL expenses and fees that
                      you would incur as a shareholder of the Portfolio. The
                      expenses set forth below are for the fiscal year ended
                      January 31, 1998.
 
<TABLE>
                               <S>                                                           <C>    <C>
                                                    SHAREHOLDER TRANSACTION EXPENSES
                               --------------------------------------------------------------------------
                               Sales Load Imposed on Purchases.............................          None
                               Sales Load Imposed on Reinvested Dividends..................          None
                               Redemption Fees*+...........................................            1%
                               Exchange Fees...............................................          None
                                                      ANNUAL FUND OPERATING EXPENSES
                               --------------------------------------------------------------------------
                               Management & Administrative Expenses........................         0.20%
                               Investment Advisory Fees....................................          0.04
                               12b-1 Fees..................................................          None
                               Other Expenses
                                 Distribution Costs........................................  0.02%
                                 Miscellaneous Expenses....................................  0.02
                                                                                             ----
                               Total Other Expenses........................................          0.04
                                                                                                    -----
                                        TOTAL OPERATING EXPENSES...........................         0.28%
                                                                                                    =====
                               * Wire redemptions of less than $5,000 are subject to a $5 processing fee.
                               + The 1% fee withheld from redemption proceeds on shares redeemed or
                                 exchanged within one year of purchase is paid to the Portfolio.
</TABLE>
 
1% REDEMPTION FEE     The High Yield Corporate Portfolio is intended for
                      long-term investors who can withstand substantial price
                      fluctuation. For this reason, the Portfolio will assess a
                      1% redemption fee on shares that are redeemed or exchanged
                      out before they have been held for one year. Solely for
                      purposes of calculating the one-year holding period, the
                      Portfolio will use the "first-in, first-out" (FIFO)
                      method. That is, the date of the redemption or exchange
                      will be compared to the earliest purchase date. If this
                      holding period is less than one year, the fee will be
                      assessed. The fee will be prorated if a portion of the
                      shares being redeemed or exchanged has been held for more
                      than one year. This fee will not apply to dividend or
                      capital gain reinvestments and it is paid directly to the
                      Portfolio.
 
                      The purpose of the above table is to assist you in
                      understanding the various expenses that you would bear
                      directly or indirectly as an investor in the Portfolio.
                      The following example illustrates the expenses that you
                      would incur on a $1,000 investment over various periods,
                      assuming (1) a 5% annual rate of return and (2) redemption
                      at the end of each period.
 
<TABLE>
<CAPTION>
                               1 YEAR   3 YEARS   5 YEARS   10 YEARS
                               ------   -------   -------   --------
                               <S>      <C>       <C>       <C>
                                 $3       $9        $16       $36
</TABLE>
 
                      THIS EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF
                      PAST OR FUTURE EXPENSES OR PERFORMANCE. ACTUAL EXPENSES
                      MAY BE HIGHER OR LOWER THAN THOSE SHOWN.
- --------------------------------------------------------------------------------
 
                                        2
<PAGE>   86
FINANCIAL
HIGHLIGHTS            The following financial highlights for a share outstanding
                      throughout each period have been derived from financial
                      statements which were audited by Price Waterhouse LLP,
                      independent accountants, whose report on the financial
                      statements which contain this information was unqualified.
                      This information should be read in conjunction with the
                      Portfolio's financial statements and notes thereto, which,
                      together with the remaining portions of the Fund's 1998
                      Annual Report to Shareholders, are incorporated by
                      reference in the Statement of Additional Information and
                      in this Prospectus, and which appear, along with the
                      report of Price Waterhouse LLP, in the Fund's 1998 Annual
                      Report to Shareholders. For a more complete discussion of
                      the Fund's performance, please see the Fund's 1998 Annual
                      Report to Shareholders which may be obtained without
                      charge by writing to the Fund or by calling our Investor
                      Information Department at 1-800-662-7447.
 
   
<TABLE>
<S>                              <C>      <C>       <C>       <C>       <C>       <C>       <C>      <C>      <C>      <C>    <C>
                                 ------------------------------------------------------------------------------------------------
                                                                   HIGH YIELD CORPORATE PORTFOLIO
                                 ------------------------------------------------------------------------------------------------
                                                                       YEAR ENDED JANUARY 31,
                                 ------------------------------------------------------------------------------------------------
                                   1998      1997      1996      1995      1994      1993     1992     1991     1990     1989
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE,
  BEGINNING OF YEAR............   $7.87     $7.89     $7.24     $8.14     $7.56     $7.27    $6.19    $7.31    $8.44    $8.53
                                  -----     -----     -----     -----     -----     -----    -----    -----    -----   ------
INVESTMENT OPERATIONS
  Net Investment Income........    .688      .688      .678      .679      .695      .727     .770     .904    1.004    1.016
  Net Realized and Unrealized
    Gain (Loss) on
    Investments................    .300     (.020)     .650     (.900)     .580      .290    1.080   (1.120)  (1.130)   (.090)
                                  -----     -----     -----     -----     -----     -----    -----    -----    -----   ------
    TOTAL FROM INVESTMENT
      OPERATIONS...............    .988      .668     1.328     (.221)    1.275     1.017    1.850    (.216)   (.126)    .926
- ---------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net
    Investment Income..........   (.688)    (.688)    (.678)    (.679)    (.695)    (.727)   (.770)   (.904)  (1.004)  (1.016)
  Distributions from Realized
    Capital Gains..............      --        --        --        --        --        --       --       --       --       --
                                  -----     -----     -----     -----     -----     -----    -----    -----    -----   ------
    TOTAL DISTRIBUTIONS........   (.688)    (.688)    (.678)    (.679)    (.695)    (.727)   (.770)   (.904)  (1.004)  (1.016)
- ---------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR...   $8.17     $7.87     $7.89     $7.24     $8.14     $7.56    $7.27    $6.19    $7.31    $8.44
=================================================================================================================================
TOTAL RETURN*..................   13.14%     9.01%    19.01%    (2.52)%   17.54%    14.68%   31.27%   (3.21)%  (1.84)%  11.41%
=================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions)...................  $4,747    $3,674    $3,007    $2,162    $2,625    $2,184   $1,593     $699     $828   $1,234
Ratio of Total Expenses to
  Average Net Assets...........    0.28%     0.29%     0.34%     0.34%     0.32%     0.34%    0.34%    0.40%    0.38%    0.41%
Ratio of Net Investment Income
  to Average Net Assets........    8.63%     8.92%     8.85%     9.13%     8.81%     9.82%   11.13%   13.35%   12.56%   12.07%
Portfolio Turnover Rate........      45%       23%       38%       33%       51%       83%      44%      61%      41%      48%
* Returns exclude 1% fee applied to shares redeemed or exchanged within one year of purchase.
- ---------------------------------------------------------------------------------------------------------------------------------
</TABLE>
    
 
YIELD AND
TOTAL RETURN          From time to time the Portfolio may advertise its yield
                      and total return. Both yield and total return figures are
                      based on historical earnings and are not intended to
                      indicate future performance. The "total return" of the
                      Portfolio refers to the average annual compounded rates of
                      return over one-, five- and ten-year periods or for the
                      life of the Portfolio (as stated in the advertisement)
                      that would equate an initial amount invested at the
                      beginning of a stated period to the ending redeemable
                      value of the investment, assuming the reinvestment of all
                      dividend and capital gains distributions.
 
                      In accordance with industry guidelines set forth by the
                      U.S. Securities and Exchange Commission, the "30-day
                      yield" of the Portfolio is calculated by dividing
 
                                        3
<PAGE>   87
 
                      net investment income per share earned during a 30-day
                      period by the net asset value per share on the last day of
                      the period. Net investment income includes interest and
                      dividend income earned on the Portfolio's securities; it
                      is net of all expenses and all recurring and nonrecurring
                      charges that have been applied to all shareholder
                      accounts. The yield calculation assumes that net
                      investment income earned over 30 days is compounded
                      monthly for six months and then annualized. Methods used
                      to calculate advertised yields are standardized for all
                      stock and bond mutual funds. However, these methods differ
                      from the accounting methods used by the Portfolio to
                      maintain its books and records, and so the advertised
                      30-day yield may not fully reflect the income paid to an
                      investor's account or the yield reported in the
                      Portfolio's Reports to Shareholders.
 
                      Additionally, the Portfolio may compare its performance to
                      that of the Lehman Brothers High Yield Index and may
                      advertise its duration, a measure of the Portfolio's
                      sensitivity to interest rate changes.
- --------------------------------------------------------------------------------
INVESTMENT
OBJECTIVE             The High Yield Corporate Portfolio is part of Vanguard
                      Fixed Income Securities Fund, a no-load, open-end,
                      diversified investment company that seeks to provide
                      investors with a high level of income consistent with the
                      maintenance of principal and liquidity. There is no
                      assurance that the Portfolio will achieve its stated
                      objective.
 
                      The investment objective of the Portfolio is not
                      fundamental and so may be changed by the Board of
                      Directors without shareholder approval. Any such change
                      could result in the Portfolio having an investment
                      objective different from the objective which a shareholder
                      considered appropriate at the time of investment in the
                      Portfolio. However, shareholders would be notified prior
                      to any material change in the Portfolio's objective.
- --------------------------------------------------------------------------------
INVESTMENT
POLICIES
THE PORTFOLIO INVESTS
IN LOW-QUALITY,
HIGH-RISK BONDS       The High Yield Corporate Portfolio invests in a
                      diversified portfolio of high-yielding corporate debt
                      securities (so-called "junk bonds"). Under normal
                      circumstances, at least 80% of the Portfolio's assets will
                      be invested in high-yield corporate debt obligations rated
                      B or better by Moody's Investors Service, Inc. ("Moody's")
                      or Standard & Poor's Corporation ("Standard & Poor's").
                      Not more than 20% of the High Yield Corporate Portfolio's
                      assets may be invested in debt securities which are rated
                      less than B or unrated, and convertible securities and
                      preferred stocks. The Portfolio may invest up to 25% of
                      its assets in cash reserves and U.S. Government securities
                      (including repurchase agreements collateralized by U.S.
                      Treasury or U.S. Government agency securities) under
                      unusual market conditions for temporary defensive
                      measures. The Portfolio is managed without regard to tax
                      ramifications.
 
                      The High Yield Corporate Portfolio will not invest in
                      securities that, at the time of initial investment, are
                      rated less than Caa by Moody's or CCC by Standard &
                      Poor's. Securities that are subsequently downgraded in
                      quality below Caa or CCC may continue to be held by the
                      Portfolio, and will be sold only if the Portfolio's
                      adviser believes it would be advantageous to do so. In
                      addition, the credit quality of unrated
 
                                        4
<PAGE>   88
 
                      securities purchased by the Portfolio must be, in the
                      opinion of the Portfolio's adviser, at least equivalent to
                      a Caa rating by Moody's or a CCC rating by Standard &
                      Poor's.
 
                      Securities rated less than Baa by Moody's or BBB by
                      Standard & Poor's are classified as non-investment grade
                      securities. Such securities carry a high degree of risk
                      and are considered speculative by the major credit rating
                      agencies. The following are excerpts from the Moody's and
                      Standard & Poor's definitions for speculative grade debt
                      obligations:
 
                         Moody's: Ba-rated bonds have "speculative elements,"
                         their future "cannot be considered assured," and
                         protection of principal and interest is "moderate" and
                         "not well safeguarded." B-rated bonds "lack
                         characteristics of a desirable investment" and the
                         assurance of interest or principal payments "may be
                         small." Caa-rated bonds are "of poor standing" and "may
                         be in default" or may have "elements of danger with
                         respect to principal or interest."
 
                         Standard & Poor's: BB-rated bonds have "less near-term
                         vulnerability to default" than B- or CCC-rated
                         securities but face "major ongoing uncertainties . . .
                         which may lead to inadequate capacity" to pay interest
                         or principal. B-rated bonds have a "greater
                         vulnerability to default" than BB-rated bonds and the
                         ability to pay interest or principal will likely be
                         impaired by adverse business conditions. CCC-rated
                         bonds have a "currently identifiable vulnerability to
                         default" and, without favorable business conditions,
                         will be unable to repay interest and principal.
 
                      Credit quality in the high-yield bond market can change
                      suddenly and unexpectedly, and even recently-issued credit
                      ratings may not fully reflect the actual risks posed by a
                      particular high-yield security. For these reasons, it is
                      the High Yield Corporate Portfolio's policy not to rely
                      primarily on ratings issued by established credit rating
                      agencies, but to utilize such ratings in conjunction with
                      the Portfolio adviser's own independent and ongoing review
                      of credit quality.
 
                      In the past, the High Yield Corporate Portfolio has not
                      invested in non-income-producing high-yield
                      securities -- such as zero coupon bonds, which pay
                      interest only at maturity, or payment-in-kind bonds, which
                      pay interest in the form of additional securities.
                      Although it has no present plans to do so, the Portfolio
                      may invest up to 5% of its assets in such securities in
                      the future.
 
                      The High Yield Corporate Portfolio may also hold
                      asset-backed securities, as well as U.S.
                      dollar-denominated debt securities issued by foreign
                      governments, their agencies and instrumentalities,
                      supranational entities and companies located outside the
                      U.S. The Portfolio may also invest in bond (interest rate)
                      futures and options to a limited extent. See
                      "Implementation of Policies" for a description of these
                      investment practices of the Portfolio.
 
                                                 * * *
                      The Portfolio is responsible for voting the shares of all
                      securities it holds.
- --------------------------------------------------------------------------------
 
                                        5
<PAGE>   89
 
INVESTMENT RISKS
THE PORTFOLIO IS
SUBJECT TO INTEREST
RATE, INCOME, CREDIT
AND MANAGER RISK      As a mutual fund investing in fixed income securities, the
                      Portfolio is subject primarily to interest rate, income,
                      credit and manager risk. INTEREST RATE RISK is the
                      potential for a decline in bond prices due to rising
                      interest rates. In general, bond prices vary inversely
                      with interest rates. When interest rates rise, bond prices
                      generally fall. Conversely, when interest rates fall, bond
                      prices generally rise. The change in price depends on
                      several factors, including the bond's maturity date. In
                      general, bonds with longer maturities are more sensitive
                      to interest rates than bonds with shorter maturities.
 
                      As an illustration of interest rate risk, the charts below
                      depict the effect of a one and two percentage point change
                      in interest rates on three bonds of varying maturities:
 
                       PERCENT CHANGE IN THE PRICE OF A PAR BOND YIELDING 7.5%
 
<TABLE>
<CAPTION>
                                                                           1 PERCENTAGE         1 PERCENTAGE
                                                                              POINT                POINT
                                                                           INCREASE IN          DECREASE IN
                                           STATED MATURITY                INTEREST RATES       INTEREST RATES
                                           ---------------                --------------       --------------
                               <S>                                      <C>                  <C>
                               Short-Term (2.5 years)                         - 2.2%                + 2.3%
                               Intermediate-Term (10 years)                   - 6.6%                + 7.3%
                               Long-Term (20 years)                           - 9.5%                +11.1%
</TABLE>
 
<TABLE>
<CAPTION>
                                                                           2 PERCENTAGE         2 PERCENTAGE
                                                                              POINT                POINT
                                                                           INCREASE IN          DECREASE IN
                                           STATED MATURITY                INTEREST RATES       INTEREST RATES
                                           ---------------                --------------       --------------
                               <S>                                      <C>                  <C>
                               Short-Term (2.5 years)                         - 4.3%                + 4.6%
                               Intermediate-Term (10 years)                   -12.7%                +15.2%
                               Long-Term (20 years)                           -17.8%                +24.1%
</TABLE>
 
                      These charts are intended to provide you with guidelines
                      for determining the degree of interest rate risk you may
                      be willing to assume. The yield and price changes shown
                      should not be taken as representative of the Portfolio's
                      current or future yield or expected changes in the
                      Portfolio's share price.
 
                      The Portfolio is also subject to INCOME RISK which is the
                      potential for a decline in the Portfolio's income due to
                      falling market interest rates.
 
                      In addition to interest rate and income risks, the
                      Portfolio is subject to credit risk. CREDIT RISK, also
                      known as default risk, is the possibility that a bond
                      issuer will fail to make timely payments of interest or
                      principal to the Portfolio. The credit risk of the
                      Portfolio depends on the quality of its investments.
                      Reflecting their higher risks, lower-quality bonds
                      generally offer higher yields (all other factors being
                      equal).
 
   
                      Finally, the investment adviser manages the Portfolio
                      according to the traditional methods of "active"
                      investment management, which involve the buying and
                      selling of securities based upon economic, financial and
                      market analysis and investment judgment. MANAGER RISK
                      refers to the possibility that the Portfolio's investment
                      adviser may fail to execute the Portfolio's investment
                      strategy effectively. As a result, the Portfolio may fail
                      to achieve its stated objective.
    
 
                                        6
<PAGE>   90
 
THE PORTFOLIO POSES
SUBSTANTIAL RISKS
                      The High Yield Corporate Portfolio is exposed to a
                      substantial degree of credit risk. The medium- and
                      low-grade bonds held by the Portfolio are considered
                      speculative by traditional investment standards.
                      High-yield bonds may be issued as a consequence of
                      corporate restructurings, such as leveraged buyouts,
                      mergers, acquisitions, debt recapitalizations, or similar
                      events. Also, high-yield bonds are often issued by
                      smaller, less creditworthy companies or by highly
                      leveraged (indebted) firms, which are generally less able
                      than more financially stable firms to make scheduled
                      payments of interest and principal. The risks posed by
                      bonds issued under such circumstances are substantial.
 
                      In an effort to minimize credit risk, the High Yield
                      Corporate Portfolio diversifies its holdings widely among
                      many issuers. As of January 31, 1998, the Portfolio held
                      securities of 171 corporate issuers, and the Portfolio's
                      holdings had the following credit quality characteristics:
 
<TABLE>
<CAPTION>
                                                             PERCENT OF
                                        INVESTMENT           INVESTMENTS
                               ----------------------------  -----------
                               <S>                           <C>
                               U.S. Treasury Securities            6%
                               Cash Reserves                       3
                               Corporate Bonds
                                 Aa/AA                             0
                                 Baa/BBB                           0
                                 Ba/BB                            36
                                 B                                55
                                 Caa/CC                            0
                                 Nonrated                          0
                                                                 ---
                                                                 100%
</TABLE>
 
                      In the past, the high yields from a portfolio of low-grade
                      bonds have more than compensated for the higher default
                      rates on such securities. However, there can be no
                      assurance that diversification will protect the Portfolio
                      from widespread bond defaults brought about by a sustained
                      economic downturn, or that yields will continue to offset
                      default rates on high-yield bonds in the future. A
                      long-term track record on bond default rates, such as that
                      for investment grade corporate bonds, does not exist for
                      the high-yield market. It may be that future default rates
                      on high-yield bonds will be more widespread and higher
                      than in the past, especially during periods of
                      deteriorating economic conditions.
 
                      The share price of the High Yield Corporate Portfolio will
                      be influenced not only by changing interest rates, but
                      also by the bond market's perception of credit quality and
                      the outlook for economic growth. When economic conditions
                      appear to be deteriorating, low- and medium-rated bonds
                      may decline in market value due to investors' heightened
                      concern over credit quality, regardless of prevailing
                      interest rates.
 
                      Especially at such times, trading in the secondary market
                      for high-yield bonds may become thin and market liquidity
                      may be significantly reduced. Even under normal
                      conditions, the market for high-yield bonds may be less
                      liquid than the market for investment grade corporate
                      bonds. There are fewer securities dealers in the
 
                                        7
<PAGE>   91
 
                      high-yield market, and purchasers of high-yield bonds are
                      concentrated among a smaller group of securities dealers
                      and institutional investors.
 
                      In periods of reduced market liquidity, high-yield bond
                      prices may become more volatile, and both the high-yield
                      market and the Portfolio may experience sudden and
                      substantial price declines. Also, there may be significant
                      disparities in the prices quoted for high-yield securities
                      by various dealers. Under such conditions, the Portfolio
                      may find it difficult to value its securities accurately.
                      The Portfolio may also be forced to sell securities at a
                      significant loss in order to meet shareholder redemptions.
 
                      Under unusual circumstances, the Portfolio may hold a
                      significant portion of its assets in U.S. Government
                      obligations and cash reserves for temporary defensive
                      purposes. As of January 31, 1998, for example, such
                      securities represented approximately 10% of the
                      Portfolio's assets.
 
                      Besides credit and liquidity concerns, prices for
                      high-yield bonds may be affected by legislative and
                      regulatory developments. For example, from time to time,
                      Congress has considered legislation to restrict or
                      eliminate the corporate tax deduction for interest
                      payments or to regulate corporate restructurings such as
                      takeovers or mergers. Such legislation may significantly
                      depress the prices of outstanding high-yield bonds.
 
                      Overall, investors should expect that the High Yield
                      Corporate Portfolio may fluctuate in price independently
                      of the broad bond market and prevailing interest rate
                      trends, and that price volatility at times may be very
                      high, especially as a result of credit concerns, market
                      liquidity, and anticipated or actual legislative and
                      regulatory changes.
- --------------------------------------------------------------------------------
WHO SHOULD
INVEST
                      The High Yield Corporate Portfolio is designed for
                      aggressive investors willing to take substantial risks in
                      pursuit of potentially higher rewards. Since the High
                      Yield Corporate Portfolio invests in securities that are
                      considered speculative by traditional investment
                      standards, an investment in the Portfolio should represent
                      only a limited portion of a balanced investment program
                      for most investors. Because of the risks associated with
                      bond investments, the Portfolio is intended to be a
                      long-term investment vehicle and is not designed to
                      provide investors with a means of speculating on
                      short-term bond market movements.
 
                      Investors who engage in excessive account activity
                      generate additional costs which are borne by all of the
                      Portfolio's shareholders. In order to minimize such costs
                      the Portfolio has adopted the following policies. The
                      Portfolio reserves the right to reject any purchase
                      request (including exchange purchases from other Vanguard
                      portfolios) that is reasonably deemed to be disruptive to
                      efficient portfolio management, either because of the
                      timing of the investment or previous excessive trading by
                      the investor. Additionally, the Portfolio has adopted
                      exchange privilege limitations as described in the section
                      "Exchange Privilege Limitations." Finally, the Portfolio
                      reserves the right to suspend the offering of its shares.
- --------------------------------------------------------------------------------
 
                                        8
<PAGE>   92
 
IMPLEMENTATION
OF POLICIES
THE PORTFOLIO MAY
INVEST IN REPURCHASE
AGREEMENTS            The Portfolio utilizes a variety of investment practices
                      in pursuit of its objective.
 
   
                      The Portfolio may invest in repurchase agreements
                      according to the restrictions and limitations set forth in
                      "Investment Limitations." A repurchase agreement is a
                      means of investing monies for a short period. In a
                      repurchase agreement, a seller -- a U.S. commercial bank
                      or recognized U.S. securities dealer -- sells securities
                      to a Portfolio and agrees to repurchase the securities at
                      the Portfolio's cost plus interest within a specified
                      period (normally one day). In these transactions, the
                      securities purchased by the Portfolio will have a total
                      value equal to or in excess of the value of the repurchase
                      agreement, and will be held by the Portfolio's Custodian
                      Bank until repurchased.
    
 
                      The use of repurchase agreements involves certain risks.
                      For example, if the other party to the agreement defaults
                      on its obligation to repurchase the underlying security at
                      a time when the value of the security has declined, the
                      Portfolio may incur a loss upon disposition of the
                      security. If the other party to the agreement becomes
                      insolvent and subject to liquidation or reorganization
                      under the Bankruptcy Code or other laws, a court may
                      determine that the underlying security is collateral for a
                      loan by the Portfolio and not within the control of the
                      Portfolio. As a result, the Portfolio's ability to realize
                      on such collateral may be automatically stayed. Finally,
                      it is possible that the Portfolio may not be able to
                      substantiate its interest in the underlying security and
                      may be deemed an unsecured creditor of the other party to
                      the agreement. While the Portfolio's management
                      acknowledges these risks, it is expected that they can be
                      controlled through careful monitoring procedures.
 
THE PORTFOLIO MAY OWN
RESTRICTED OR ILLIQUID
SECURITIES
                      The Portfolio may own restricted or illiquid securities to
                      a limited extent. Restricted or illiquid securities are
                      securities which are not freely marketable or which are
                      subject to restrictions upon sale under the Securities Act
                      of 1933. The Portfolio may invest up to 15% of its net
                      assets in restricted or illiquid securities. The Fund's
                      Board of Directors may from time to time determine certain
                      restricted securities known as Rule 144A securities to be
                      liquid. Such securities will not be subject to the 15%
                      limitations described above.
 
THE PORTFOLIO MAY
INVEST IN SECURITIES OF
FOREIGN ISSUERS
                      The Portfolio may hold securities of foreign issuers, but
                      all such securities must be denominated in U.S. dollars.
                      Securities of foreign issuers may trade in U.S. or foreign
                      securities markets. Securities of foreign issuers may
                      involve investment risks that are different from those of
                      domestic issuers. Such risks include the effect of foreign
                      economic policies and conditions, future political and
                      economic developments, and the possible imposition of
                      exchange controls or other foreign governmental
                      restrictions on foreign debt issuers. There may also be
                      less publicly available information about a foreign issuer
                      than a domestic issuer of securities. Foreign issuers are
                      generally not subject to the uniform accounting, auditing
                      and financial reporting standards that apply to domestic
                      issuers. Also, foreign debt markets may be characterized
                      by lower liquidity, greater price volatility, and higher
                      transaction costs. Additionally, it may be difficult to
                      obtain or enforce a legal judgment in a foreign court.
 
                                        9
<PAGE>   93
 
THE PORTFOLIO MAY
INVEST IN FUTURES
CONTRACTS, OPTIONS,
AND OTHER DERIVATIVE
SECURITIES
                      The Portfolio may invest in futures contracts and options
                      to a limited extent. Specifically, the Portfolio may enter
                      into futures contracts provided that not more than 5% of
                      its assets is required as a futures contract margin
                      deposit; in addition, the Portfolio may enter into futures
                      contracts and options transactions only to the extent that
                      obligations under such contracts or transactions represent
                      not more than 20% of the Portfolio's assets.
 
                      Futures contracts and options may be used for several
                      reasons: to maintain cash reserves while simulating full
                      investment, to facilitate trading, to reduce transaction
                      costs, or to seek higher investment returns when a futures
                      contract is priced more attractively than the underlying
                      equity security or index. The Portfolio intends to use
                      futures contracts only for bona fide hedging purposes and
                      will not use futures contracts or options for speculative
                      purposes.
 
FUTURES CONTRACTS
AND OPTIONS POSE
CERTAIN RISK
                      The primary risks associated with the use of futures
                      contracts and options are: (i) imperfect correlation
                      between the change in market value of the bonds held by
                      the Portfolio and the prices of futures contracts and
                      options; and (ii) possible lack of a liquid secondary
                      market for a futures contract and the resulting inability
                      to close a futures position prior to its maturity date.
                      The risk of imperfect correlation will be minimized by
                      investing only in those contracts whose price fluctuations
                      are expected to resemble those of the Portfolio's
                      underlying securities. The risk that the Portfolio will be
                      unable to close out a futures position will be minimized
                      by entering into such transactions on a national exchange
                      with an active and liquid secondary market.
 
                      The risk of loss in trading futures contracts in some
                      strategies can be substantial, due both to the low margin
                      deposits required, and the extremely high degree of
                      leverage involved in futures pricing. As a result, a
                      relatively small price movement in a futures contract may
                      result in immediate and substantial loss (as well as gain)
                      to the investor. When investing in futures contracts, the
                      Portfolio will segregate cash or other liquid portfolio
                      securities in the amount of the underlying obligation.
 
DERIVATIVE
INVESTING
                      Derivatives are instruments whose value is linked to or
                      derived from an underlying security or index. The most
                      common are futures and options which are described above.
                      Other derivatives include swaps, inverse floaters, IO's
                      (interest only), and PO's (principal only). Derivatives
                      may be traded separately on exchanges or in the
                      over-the-counter market, or they may be imbedded in other
                      securities. The most common imbedded derivative is the
                      call option attached to or imbedded in a callable
                      government or callable corporate bond. The owner of a
                      traditional callable bond holds a combination of a long
                      position in a non-callable bond and a short position in a
                      call option on that bond, i.e. the bond issuer has the
                      right to call the bond away from the holder of the bond.
                      Any of these instruments may also be used individually or
                      in combination to hedge against unfavorable changes in
                      interest rates, or to speculate on anticipated changes in
                      interest rates. Derivatives may be structured with no or a
                      high degree of leverage. When derivatives are used as
                      hedges, the risk incurred is that the derivative
                      instrument's value may change differently than the value
                      of the security being hedged. This "basis risk" is
                      generally lower than the risk associated with an unhedged
                      position in the security being hedged. Some deriva-
 
                                       10
<PAGE>   94
 
                      tives may entail liquidity risk, i.e. the risk that the
                      instrument cannot be sold at a reasonable price in highly
                      volatile markets. Leveraged derivatives used for
                      speculation are very volatile, and therefore, very risky.
                      However, the Portfolio will only utilize derivatives for
                      hedging or arbitrage purposes, and not for speculative
                      purposes. Over-the-counter derivatives involve a
                      counterparty risk, i.e. the risk that the individual or
                      institution on the other side of the agreement will not or
                      cannot meet their obligations under the derivative
                      agreement.
 
THE PORTFOLIO MAY LEND
ITS SECURITIES
                      The Portfolio may lend its investment securities to
                      qualified institutional investors for either short-term or
                      long-term purposes of realizing additional income. Loans
                      of securities by a Portfolio will be collateralized by
                      cash, letters of credit, or securities issued or
                      guaranteed by the U.S. Government or its agencies. The
                      collateral will equal at least 100% of the current market
                      value of the loaned securities, and such loans may not
                      exceed 33 1/3% of the value of the Portfolio's total
                      assets (including any collateral obtained in connection
                      with such loans).
 
THE PORTFOLIO
MAY INVEST IN
ASSET-BACKED
SECURITIES
                      The Portfolio may invest in asset-backed securities. These
                      securities represent partial ownership in pools of
                      consumer or commercial loans--such as mortgage or
                      automobile loans, credit card balances, equipment lease
                      loans, and collateralized bond obligations (bonds backed
                      by other securities).
 
                      Besides being backed by the loans or other assets in the
                      pool, many of these securities come with credit
                      enhancements as additional protection against default.
                      Such credit enhancements could include
                      over-collateralization or insurance coverage provided by a
                      highly rated (usually AAA) institution other than the
                      security's issuer.
 
                      The value of asset-backed securities ultimately depends on
                      whether the borrowers repay the underlying loans, and
                      whether the credit enhancements, if any, are adequate.
                      Despite any credit enhancements, the value of an
                      asset-backed security may fluctuate because of several
                      factors, including:
 
                      - The market's perception of the value of the assets
                        backing the security.
 
                      - The creditworthiness of the agent in charge of
                        collecting loan payments and passing them through to
                        security holders, the firm that originated the loans,
                        and the institution providing any credit insurance or
                        guarantees.
 
                      - The nature of any insurance or other credit
                        enhancements.
 
                      Another risk of asset-backed securities, especially in
                      periods of declining interest rates, is that borrowers may
                      prepay the underlying loans. These prepayments shorten the
                      weighted average life of an asset-backed security and may
                      lower its return.
 
PORTFOLIO TURNOVER
IS NOT EXPECTED TO
EXCEED 100%           Although it generally seeks to invest for the long term,
                      the Portfolio retains the right to sell securities
                      regardless of how long they have been held. It is
                      anticipated that the annual portfolio turnover rate for
                      the Portfolio will not exceed 100%. A 100%
 
                                       11
<PAGE>   95
 
                      turnover rate would occur, for example, if all of the
                      securities in the Portfolio were replaced within one year.
- --------------------------------------------------------------------------------
 
INVESTMENT
LIMITATIONS
THE PORTFOLIO HAS
ADOPTED CERTAIN
FUNDAMENTAL
LIMITATIONS
                      The Portfolio has adopted limitations on some of its
                      investment policies. Some of these limitations are that
                      the Portfolio will not:
 
                      (a) with respect to 75% of its assets, invest more than 5%
                          of the value of its assets in the securities of any
                          single company or purchase more than 10% of the voting
                          securities of any issuer (except for securities issued
                          or guaranteed by the U.S. Government or any of its
                          agencies or instrumentalities);
 
                      (b) invest more than 5% of its assets in the securities of
                          companies that have a continuous operating history of
                          less than three years;
 
                      (c) invest more than 25% of its assets in any one
                          industry, provided that: (i) this limitation does not
                          apply to obligations issued or guaranteed by the U.S.
                          Government or its agencies or instrumentalities; (ii)
                          utility companies will be divided according to their
                          services (for example, gas, gas transmission,
                          electric, electric and gas, and telephone will each be
                          considered a separate industry); and (iii) financial
                          service companies will be classified according to the
                          end users of their services (for example, automobile
                          finance, bank finance, and diversified finance will be
                          considered as separate industries);
 
                      (d) borrow money, except that the Portfolio may borrow
                          from banks (or through reverse repurchase agreements),
                          for temporary or emergency (not leveraging) purposes,
                          including the meeting of redemption requests which
                          might otherwise require the untimely disposition of
                          securities, in an amount not exceeding 15% of the
                          value of the Portfolio's net assets (including the
                          amount borrowed and the value of any outstanding
                          reverse repurchase agreements) at the time the
                          borrowing is made. Whenever borrowings exceed 5% of
                          the value of the Portfolio's net assets, the Portfolio
                          will not make any additional investments; and
 
                      (e) pledge, mortgage or hypothecate its assets to an
                          extent greater than 5% of the value of its total
                          assets.
 
                      A complete list of the Portfolio's investment limitations
                      can be found in the Statement of Additional Information.
                      These limitations are fundamental and may be changed only
                      by approval of a majority of the Fund's shareholders.
   
- --------------------------------------------------------------------------------
MANAGEMENT OF
THE PORTFOLIO
VANGUARD ADMINISTERS
AND DISTRIBUTES THE
PORTFOLIO
                      The Portfolio is one of nine Portfolios of Vanguard Fixed
                      Income Securities Fund (the "Fund"), a member of The
                      Vanguard Group of Investment Companies, a family of more
                      than 30 investment companies with more than 95 distinct
                      portfolios and total assets in excess of $370 billion.
                      Through their jointly-owned subsidiary, The Vanguard
                      Group, Inc. ("Vanguard"), the Portfolio and the other
                      funds in the Group obtain at cost virtually all of their
                      corporate management, administrative, shareholder
                      accounting and distribution services. Vanguard also
                      provides investment advisory services on an at-cost basis
                      to certain Vanguard funds. As a result of Vanguard's
                      unique corporate structure, the Vanguard funds have costs
                      substantially lower than those of most competing mutual
                      funds. In 1997, the average
    
 
                                       12
<PAGE>   96
 
                      expense ratio (annual costs including advisory fees
                      divided by total net assets) for the Vanguard funds
                      amounted to approximately 0.28% compared to an average of
                      1.24% for the mutual fund industry (data provided by
                      Lipper Analytical Services).
 
                      The Officers of the Portfolio manage its day-to-day
                      operations and are responsible to the Portfolio's Board of
                      Directors. The Directors set broad policies for the
                      Portfolio and choose its Officers. A list of the Directors
                      and Officers of the Fund and a statement of their present
                      positions and principal occupations during the past five
                      years can be found in the Statement of Additional
                      Information.
 
                      Vanguard employs a supporting staff of management and
                      administrative personnel needed to provide the requisite
                      services to the funds and also furnishes the funds with
                      necessary office space, furnishings and equipment. Each
                      fund pays its share of Vanguard's net expenses, which are
                      allocated among the funds under methods approved by the
                      Board of Directors (Trustees) of each fund. In addition,
                      each fund bears its own direct expenses, such as legal,
                      auditing and custodian fees.
 
                      Vanguard also provides distribution and marketing services
                      to the Vanguard funds. The funds are available to
                      investors on a no-load basis (i.e., there are no sales
                      commissions or 12b-1 fees). However, each fund bears its
                      share of the Group's distribution costs.
- --------------------------------------------------------------------------------
INVESTMENT
ADVISER
WELLINGTON
MANAGEMENT
COMPANY, LLP
MANAGES INVESTMENTS
FOR THE PORTFOLIO
                      Under an investment advisory agreement with the Fund dated
                      May 1, 1996, Wellington Management Company, LLP ("WMC"),
                      75 State Street, Boston, MA 02109, manages the investment
                      and reinvestment of assets in the High Yield Corporate
                      Portfolio, and continuously reviews, supervises and
                      administers the investment program of the Portfolio. WMC
                      discharges its responsibilities subject to the control of
                      the Officers and Directors of the Fund.
 
                      WMC is a professional investment counseling firm which
                      globally provides investment services to investment
                      companies, institutions and individuals. Among the clients
                      of WMC are more than 10 of the investment companies of The
                      Vanguard Group. As of January 31, 1998, WMC held
                      discretionary management authority with respect to more
                      than $177 billion of assets. WMC and its predecessor
                      organizations have provided investment advisory services
                      to investment companies since 1928 and to investment
                      counseling clients since 1960.
 
                      Earl E. McEvoy, Senior Vice President of WMC, serves as
                      portfolio manager of the High Yield Corporate Portfolio, a
                      position he has held since 1984. Mr. McEvoy also manages
                      the Fund's Long-Term Corporate Portfolio, as well as the
                      Vanguard Preferred Stock Fund, the High Yield Bond
                      Portfolio of Vanguard Variable Insurance Fund and the bond
                      components of the Utilities Income Portfolio of Vanguard
                      Specialized Portfolios and Vanguard/Wellesley Income Fund.
                      Mr. McEvoy has been associated with WMC for 20 years and
                      is supported by research and other investment services
                      provided by the professional staff of WMC.
 
                      Under the Fund's investment advisory agreement, the fee
                      paid to WMC is based on the total assets of the High Yield
                      Corporate Portfolio and the total assets of two other
                      Portfolios of Vanguard Fixed Income Securities Fund,
                      managed by WMC (GNMA and
 
                                       13
<PAGE>   97
 
                      Long-Term Corporate Portfolios). Each of the three
                      Portfolios separately pays WMC a fee at the end of each
                      fiscal quarter, calculated by applying a quarterly rate
                      based on an annual percentage rate, to the average
                      month-end net assets of each Portfolio.
 
<TABLE>
<CAPTION>
                                    NET ASSETS        ANNUAL RATE
                               ----------------       -----------
                               <S>                    <C>
                               First $1 billion          .060%
                               Next $1 billion           .040%
                               Next $1 billion           .030%
                               Over $3 billion           .025%
</TABLE>
 
                      Separate fee schedules apply to the GNMA Portfolio and the
                      Long-Term Corporate Portfolio. For the fiscal year ended
                      January 31, 1998, the High Yield Corporate Portfolio paid
                      annual advisory fees to WMC equal to .04 of 1% of average
                      net assets.
 
                      The adviser is authorized to choose brokers or dealers to
                      handle the purchase and sale of the Portfolio's
                      securities, and is directed to get the best available
                      price and most favorable execution from these brokers with
                      respect to all transactions. At times, the adviser may
                      choose brokers who charge higher commissions in the
                      interests of obtaining better execution of a transaction.
                      If more than one broker can obtain the best available
                      price and favorable execution of a transaction, then the
                      adviser is authorized to choose a broker who, in addition
                      to executing the transaction, will provide research
                      services to the adviser or the Portfolio. However, the
                      adviser will not pay higher commissions specifically for
                      the purpose of obtaining research services. The Portfolio
                      may direct the adviser to use a particular broker for
                      certain transactions in exchange for commission rebates or
                      research services provided to the Portfolio.
- --------------------------------------------------------------------------------
DIVIDENDS, CAPITAL
GAINS AND TAXES
DIVIDENDS ARE PAID ON
THE FIRST BUSINESS DAY
OF EACH MONTH         Dividends consisting of virtually all of the ordinary
                      income of the Portfolio are declared daily and are payable
                      to shareholders of record at the time of declaration. Such
                      dividends are paid on the first business day of each
                      month. Net capital gains distributions, if any, will be
                      made annually.
 
                      The Portfolio's dividends and capital gains distributions
                      may be reinvested in additional shares or received in
                      cash. See "Choosing a Distribution Option" for a
                      description of these distribution methods.
 
                      In order to satisfy certain requirements of the Tax Reform
                      Act of 1986, the Portfolio may declare year-end dividend
                      and capital gains distributions during December. Such
                      distributions, if received by shareholders by January 31,
                      are deemed to have been paid by the Portfolio and received
                      by shareholders on December 31 of the prior year.
 
                      The Portfolio intends to continue to qualify for taxation
                      as a "regulated investment company" under the Internal
                      Revenue Code so that it will not be subject to federal
                      income tax to the extent its income is distributed to
                      shareholders. Dividends paid by the Portfolio from net
                      investment income, whether received in cash or reinvested
                      in additional shares, will be taxable to shareholders as
                      ordinary income. For corporate investors, dividends paid
                      by the Portfolio from net investment income will generally
                      not qualify for the intercorporate dividends-received
                      deduction.
 
                                       14
<PAGE>   98
 
                      Distributions paid by the Portfolio from long-term capital
                      gains, whether received in cash or reinvested in
                      additional shares, are taxable as long-term capital gains,
                      regardless of the length of time you have owned shares in
                      the Portfolio. Long-term capital gains may be taxed at
                      different rates depending on how long the Portfolio held
                      the securities. Capital gains distributions are made when
                      the Portfolio realizes net capital gains on sales of
                      portfolio securities during the year. For the Portfolio,
                      realized capital gains are not expected to be a
                      significant or predictable part of investment return.
 
                      The Portfolio will notify you annually as to the tax
                      status of dividend and capital gains distributions paid by
                      the Portfolio. The Portfolio is managed without regard to
                      tax ramifications.
 
A CAPITAL GAIN OR LOSS
MAY BE REALIZED
UPON EXCHANGE OR
REDEMPTION            A sale of shares of the Portfolio is a taxable event and
                      may result in a capital gain or loss. A capital gain or
                      loss may be realized from an ordinary redemption of shares
                      or an exchange of shares between two mutual funds (or two
                      portfolios of a mutual fund).
 
                      Dividend distributions, capital gains distributions, and
                      capital gains or losses from redemptions and exchanges may
                      be subject to state and local taxes.
 
                      The Portfolio is required to withhold 31% of taxable
                      dividends, capital gains distributions, and redemptions
                      paid to shareholders who have not complied with IRS
                      taxpayer identification regulations. You may avoid this
                      withholding requirement by certifying on your Account
                      Registration Form your proper Social Security or employer
                      identification number and by certifying that you are not
                      subject to backup withholding.
 
                      The Portfolio has obtained a Certificate of Authority to
                      do business as a foreign corporation in Pennsylvania and
                      does business and maintains an office in that state. In
                      the opinion of counsel, the shares of the Portfolio are
                      exempt from Pennsylvania personal property taxes.
 
                      The tax discussion set forth above is included for general
                      information only. Prospective investors should consult
                      their own tax advisers concerning the tax consequences of
                      an investment in the Portfolio.
- --------------------------------------------------------------------------------
THE SHARE PRICE
OF THE PORTFOLIO      The Portfolio's share price, or "net asset value" per
                      share, is calculated by dividing the total assets of the
                      Portfolio, less all liabilities, by the total number of
                      shares outstanding. The net asset value is determined as
                      of the close of the New York Stock Exchange (the
                      "Exchange"), generally 4:00 p.m. Eastern time, on each day
                      that the Exchange is open for trading.
 
                      Short-term instruments (those acquired with remaining
                      maturities of 60 days or less) may be valued at cost, plus
                      or minus any amortized discount or premium, which
                      approximates market value.
 
                      Bonds and other fixed income securities may be valued on
                      the basis of prices provided by a pricing service when
                      such prices are believed to reflect the fair market value
                      of such securities. The prices provided by a pricing
                      service may be determined without regard to bid or last
                      sale prices of each security, but take into account
 
                                       15
<PAGE>   99
 
                      institutional-size transactions in similar groups of
                      securities as well as any developments related to specific
                      securities.
 
                      Other assets and securities for which no quotations are
                      readily available or which are restricted as to sale (or
                      resale) are valued by such methods as the Board of
                      Directors deems in good faith to reflect fair value.
 
                      The share price for the Portfolio can be found daily in
                      the mutual fund listings of most major newspapers under
                      the heading of Vanguard Funds.
   
- --------------------------------------------------------------------------------
GENERAL
INFORMATION           The Fund is a Maryland corporation. The Articles of
                      Incorporation permit the Directors to issue 4,550,000,000
                      shares of common stock, with a $.001 par value. The Board
                      of Directors has the power to designate one or more series
                      ("Portfolios") of shares of common stock and to classify
                      or reclassify any unissued shares with respect to such
                      series. Currently the Fund is offering shares of nine
                      Portfolios.
    
 
                      The shares of each Portfolio are fully paid and
                      non-assessable; have no preference as to conversion,
                      exchange, dividends, retirement or other features; and
                      have no pre-emptive rights. Such shares have
                      non-cumulative voting rights, meaning that the holders of
                      more than 50% of the shares voting for the election of
                      Directors can elect 100% of the Directors if they so
                      choose.
 
                      Annual meetings of shareholders will not be held except as
                      required by the Investment Company Act of 1940 and other
                      applicable law. An annual meeting will be held to vote on
                      the removal of a Director or Directors of the Fund if
                      requested in writing by the holders of not less than 10%
                      of the outstanding shares of the Fund.
 
                      All securities and cash for the High Yield Corporate
                      Portfolio are held by Chase Manhattan Bank, New York, NY.
                      CoreStates Bank, N.A., Philadelphia, PA holds daily cash
                      balances that are used by the Fund's Portfolios to invest
                      in repurchase agreements or securities acquired in these
                      transactions. The Vanguard Group, Inc., Valley Forge, PA,
                      serves as the Fund's Transfer and Dividend Disbursing
                      Agent. Price Waterhouse LLP serves as independent
                      accountants for the Fund and will audit its financial
                      statements annually. The Fund is not involved in any
                      litigation.
- --------------------------------------------------------------------------------
 
                                       16
<PAGE>   100
 
                               SHAREHOLDER GUIDE
 
OPENING AN
ACCOUNT AND
PURCHASING
SHARES                You may open a regular (non-retirement) account, either by
                      mail or wire. Simply complete and return an Account
                      Registration Form, and any required legal documentation,
                      indicating the amount you wish to invest. Your purchase
                      must be equal to or greater than the $3,000 minimum
                      initial investment requirement ($1,000 for Individual
                      Retirement Accounts and Uniform Gifts/Transfers to Minors
                      Act accounts, $500 minimum for an Education IRA). You must
                      open a new Individual Retirement Account by mail (IRAs may
                      not be opened by wire) using a Vanguard IRA Adoption
                      Agreement. Your purchase must be equal to or greater than
                      the $1,000 minimum initial investment requirement, but no
                      more than $2,000 if you are making a regular IRA
                      contribution. Rollover contributions are generally limited
                      to the amount withdrawn within the past 60 days from an
                      IRA or other qualified retirement plan. If you need
                      assistance with the forms or have any questions, please
                      call our Investor Information Department (1-800-662-7447).
                      Note: For other types of account registrations (e.g.,
                      corporations, associations, other organizations, trusts,
                      or powers of attorney), please call us to determine which
                      additional forms you may need.
 
                      The Portfolio's shares are purchased at the
                      next-determined net asset value after your investment has
                      been received in the form of Federal Funds. See "When Your
                      Account Will Be Credited". The Portfolio is offered on a
                      no-load basis (i.e., there are no sales commissions or
                      12b-1 fees).
 
PURCHASE RESTRICTIONS 1) Because of the risks associated with bond investments,
                         the Portfolio is intended to be a long-term investment
                         vehicle and is not designed to provide investors with a
                         means of speculating on short-term market movements.
                         Consequently, the Portfolio reserves the right to
                         reject any specific purchase (and exchange purchase)
                         request. The Portfolio also reserves the right to
                         suspend the offering of shares for a period of time.
 
                      2) Vanguard will not accept third-party checks to purchase
                         shares of the Fund. Please be sure your purchase check
                         is made payable to The Vanguard Group.
 
IMPORTANT NOTE        Potential investors should note that a 1% fee is charged
                      on redemptions or exchanges out of this Portfolio of
                      shares held for less than one year. Please see "Portfolio
                      Expenses" for more information.
 
ADDITIONAL
INVESTMENTS           Subsequent investments to regular accounts may be made by
                      mail ($100 minimum per Portfolio), wire ($1,000 minimum
                      per Portfolio), exchange from another Vanguard Fund
                      account ($100 minimum per Portfolio), or Vanguard Fund
                      Express. Subsequent investments to Individual Retirement
                      Accounts may be made by mail ($100 minimum) or exchange
                      from another Vanguard Fund account. In some instances,
                      contributions may be made by wire or Vanguard Fund
                      Express. Please call us for more information on these
                      options.
- --------------------------------------------------------------------------------
 
                                       17
<PAGE>   101
 
<TABLE>
<S>                             <C>                                         <C>
                                                                            ADDITIONAL INVESTMENTS
                                NEW ACCOUNT                                 TO EXISTING ACCOUNTS
PURCHASING BY MAIL              Please include the amount of                Additional investments should
                                your initial investment on the              include the Invest-by-Mail
Complete and sign the           registration form, make your                remittance form attached to your
enclosed Account                check payable to The Vanguard               Portfolio confirmation
Registration Form               Group-29, and mail to:                      statements. Please make your
                                                                            check payable to The Vanguard
                                THE VANGUARD GROUP                          Group-29, write your account
                                P.O. BOX 2600                               number on your check and, using
                                VALLEY FORGE, PA 19482-2600                 the return envelope provided,
                                                                            mail to the address indicated on
                                                                            the Invest-by-Mail Form.
For express or                  THE VANGUARD GROUP                          All written requests should be
registered mail,                455 DEVON PARK DRIVE                        mailed to one of the addresses
send to:                        WAYNE, PA 19087-1815                        indicated for new accounts. Do
                                                                            not send registered or express
                                                                            mail to the post office box
                                                                            address.
                                --------------------------------
PURCHASING BY WIRE                                CORESTATES BANK, N.A.
                                                  ABA 031000011
Money should be                                   CORESTATES NO. 0101 9897
wired to:                                         ATTN: VANGUARD
                                                  VANGUARD FIXED INCOME SECURITIES FUND
BEFORE WIRING                                     HIGH YIELD CORPORATE PORTFOLIO
                                                  ACCOUNT NUMBER
Please contact                                    ACCOUNT REGISTRATION
Client Services
(1-800-662-2739)
</TABLE>
 
                      To assure proper receipt, please be sure your bank
                      includes the Portfolio name, the account number Vanguard
                      has assigned to you and the eight-digit CoreStates number.
                      If you are opening a new account, you must contact our
                      Client Services Department (1-800-662-2739) before wiring
                      funds. Additionally, complete the Account Registration
                      Form and mail it to the "New Account" address above after
                      completing your wire arrangement. NOTE: Federal Funds wire
                      purchase orders will be accepted only when the Fund and
                      Custodian Bank are open for business.
- --------------------------------------------------------------------------------
PURCHASING BY
EXCHANGE (from a
Vanguard account)     You may open an account or purchase additional shares by
                      making an exchange from an existing Vanguard Fund account.
                      However, the Portfolio reserves the right to refuse any
                      exchange purchase request. Call our Client Services
                      Department (1-800-662-2739) for assistance. The new
                      account will have the same registration as the existing
                      account.
- --------------------------------------------------------------------------------
 
                                       18
<PAGE>   102
 
PURCHASING BY
FUND EXPRESS
Special Purchase and
Automatic Investment  The Fund Express Special Purchase option lets you move
                      money from your bank account to your Vanguard account on
                      an "as needed" basis. Or, if you choose the Automatic
                      Investment option, money will be moved automatically from
                      your bank account to your Vanguard account on the schedule
                      (monthly, bimonthly [every other month], quarterly,
                      semiannually or annually) you select. To establish these
                      Fund Express options, please provide the appropriate
                      information on the Account Registration Form. We will send
                      you a confirmation of your Fund Express enrollment; please
                      wait two weeks before using the service.
- --------------------------------------------------------------------------------
CHOOSING A
DISTRIBUTION
OPTION
                      You must select one of four distribution options:
 
                      1. AUTOMATIC REINVESTMENT OPTION--Both dividend and
                         capital gains distributions will be reinvested in
                         additional Portfolio shares. This option will be
                         selected for you automatically unless you specify one
                         of the other options.
 
                      2. CASH DIVIDEND OPTION--Your dividends will be paid in
                         cash and your capital gains will be reinvested in
                         additional Portfolio shares.
 
                      3. CASH CAPITAL GAINS OPTION--Your capital gains
                         distributions will be paid in cash and your dividends
                         will be reinvested in additional Portfolio shares.
 
                      4. ALL CASH OPTION--Both dividend and capital gains
                         distributions will be paid in cash.
 
                      You may change your option by calling our Client Services
                      Department (1-800-662-2739).
 
                      If a shareholder has chosen to receive dividend and/or
                      capital gains distributions in cash, and the postal or
                      other delivery service is unable to deliver checks to the
                      shareholder's address of record, we will change the
                      distribution option so that all dividends and other
                      distributions are automatically reinvested in additional
                      shares. We will not pay interest on uncashed distribution
                      checks.
 
                      In addition, an option to invest your cash dividend and/or
                      capital gains distributions in another Vanguard Fund
                      account is available. Please call our Client Services
                      Department (1-800-662-2739) for information. You may also
                      elect Vanguard Dividend Express which allows you to
                      transfer your cash dividend and/or capital gains
                      distributions automatically to your bank account. Please
                      see "Other Vanguard Services" for more information.
   
- --------------------------------------------------------------------------------
TAX CAUTION
INVESTORS SHOULD ASK
ABOUT THE TIMING OF
CAPITAL GAINS AND
DIVIDEND DISTRIBUTIONS
BEFORE INVESTING
                      Under Federal tax laws, the Portfolio is required to
                      distribute net capital gains and dividend income to
                      Portfolio shareholders. These distributions are made to
                      all shareholders who own Portfolio shares as of the
                      distribution's record date, regardless of how long the
                      shares have been owned. Purchasing shares just prior to
                      the record date could have a significant impact on your
                      tax liability for the year. For example, if you purchase
                      shares immediately prior to the record date of a sizable
                      capital gains distribution, you will be assessed taxes on
                      the amount of the capital gains distribution later paid
                      even though you owned the Portfolio shares for just a
                      short period of time. (Taxes are due on the distributions
                      even if the dividend or
    
 
                                       19
<PAGE>   103
 
   
                      capital gain is reinvested in additional Portfolio
                      shares.) While the total value of your investment will be
                      the same after the capital gains distribution -- the
                      amount of the capital gains distribution will offset the
                      drop in the net asset value of the shares -- you should be
                      aware of the tax implications the timing of your purchase
                      may have.
    
 
                      Prospective investors should, therefore, inquire about
                      potential distributions before investing. The Portfolio's
                      annual capital gains distribution normally occurs in
                      December, while income dividends are generally paid on the
                      first business day of each month. In addition, the
                      Portfolio may occasionally be required to make
                      supplemental dividend or capital gains distributions at
                      some other time during the year. For additional
                      information on distributions and taxes, see the section
                      titled "Dividends, Capital Gains and Taxes."
- --------------------------------------------------------------------------------
IMPORTANT
INFORMATION
ESTABLISHING
OPTIONAL SERVICES     The easiest way to establish optional Vanguard services on
                      your account is to select the options you desire when you
                      complete your Account Registration Form.
 
                      IF YOU WISH TO ADD OPTIONS LATER, YOU MAY NEED TO PROVIDE
                      VANGUARD WITH ADDITIONAL INFORMATION AND A SIGNATURE
                      GUARANTEE. PLEASE CALL OUR CLIENT SERVICES DEPARTMENT
                      (1-800-662-2739) FOR FURTHER ASSISTANCE.
 
SIGNATURE
GUARANTEES            For our mutual protection, we may require a signature
                      guarantee on certain written transaction requests. A
                      signature guarantee verifies the authenticity of your
                      signature and may be obtained from banks, brokers and any
                      other guarantor that Vanguard deems acceptable. A
                      SIGNATURE GUARANTEE CANNOT BE PROVIDED BY A NOTARY PUBLIC.
 
CERTIFICATES
                      Share certificates will be issued upon request. If a
                      certificate is lost, you may incur an expense to replace
                      it.
 
BROKER/DEALER
PURCHASES
                      If you purchase shares in Vanguard Funds through a
                      registered broker/dealer or investment adviser, the
                      broker/dealer or adviser may charge a service fee.
 
CANCELLING TRADES     The Fund will not cancel any trade (e.g., a purchase,
                      exchange or redemption) believed to be authentic, once the
                      trade request has been received in writing or by
                      telephone.
 
ELECTRONIC
PROSPECTUS
DELIVERY
                      You may receive a prospectus for the Portfolio or any of
                      the Vanguard Funds in an electronic format through
                      Vanguard's website at www.vanguard.com. For additional
                      information please see "Other Vanguard
                      Services -- Computer Access."
- --------------------------------------------------------------------------------
WHEN YOUR
ACCOUNT WILL
BE CREDITED           The trade date is the date on which your account is
                      credited. It is generally the day on which the Portfolio
                      receives your investment in the form of Federal Funds
                      (monies credited to the Portfolio's Custodian Bank by a
                      Federal Reserve Bank). Your trade date varies according to
                      your method of payment for your shares.
 
   
                      Purchases by check will receive a trade date the day the
                      funds are received in Good Order by Vanguard. Thus, if
                      your purchase by check is received by the close of trading
                      on the Exchange, your trade date is the business day your
                      check is received in Good Order. If your purchase is
                      received after the close of the Exchange, your trade date
                      is the second business day following receipt of your
                      check. You will begin to earn dividends
    
 
                                       20
<PAGE>   104
 
                      on the calendar day following the trade date. (For a
                      Friday trade date, you will begin earning dividends on
                      Saturday.)
 
                      For purchases by Federal Funds wire or exchange, the
                      Portfolio is credited immediately with Federal Funds.
                      Thus, if your purchase by Federal Funds wire or exchange
                      is received by the close of the Exchange, your trade date
                      is the day of receipt. If your purchase is received after
                      the close of the Exchange, your trade date is the business
                      day following receipt of your wire or exchange.
 
                      In order to prevent lengthy processing delays caused by
                      the clearing of foreign checks, Vanguard will only accept
                      a foreign check which has been drawn in U.S. dollars and
                      has been issued by a foreign bank with a U.S.
                      correspondent bank. The name of the U.S. correspondent
                      bank must be printed on the face of the foreign check.
- --------------------------------------------------------------------------------
SELLING YOUR
SHARES                You may withdraw any portion of the funds in your account
                      by redeeming shares at any time. (Please see "Important
                      Redemption Information.") You generally may initiate a
                      request by writing or by telephoning. Your redemption
                      proceeds are normally mailed, credited or
                      wired -- depending upon the method of withdrawal you have
                      previously chosen -- within two business days after the
                      receipt of the request in Good Order. No interest will
                      accrue on amounts represented by uncashed redemption
                      checks.
 
IMPORTANT NOTE        A redemption fee of 1% of the value of shares redeemed
                      will be deducted from the redemption proceeds of any
                      shares held for less than one year. This fee is paid
                      directly to the Portfolio.
 
SELLING BY MAIL       Requests should be mailed to THE VANGUARD GROUP, VANGUARD
                      FIXED INCOME SECURITIES FUND, P.O. BOX 1120, VALLEY FORGE,
                      PA 19482-1120. (For express or registered mail, send your
                      request to The Vanguard Group, Vanguard Fixed Income
                      Securities Fund, 455 Devon Park Drive, Wayne, PA
                      19087-1815.)
 
                      The redemption price of shares will be the Portfolio's net
                      asset value next determined after Vanguard has received
                      all required documents in Good Order.
- --------------------------------------------------------------------------------
DEFINITION OF
GOOD ORDER            GOOD ORDER means that the request includes the following:
 
                      1. The account number and Portfolio name.
                      2. The amount of the transaction (specified in dollars or
                         shares).
                      3. The signatures of all owners EXACTLY as they are
                         registered on the account.
                      4. Any required signature guarantees.
                      5. Any other supporting legal documentation that may be
                         required, in the case of estates, corporations, trusts
                         and certain other accounts.
                      6. Any certificates that you hold for the account.
 
                      IF YOU HAVE QUESTIONS ABOUT THIS DEFINITION AS IT PERTAINS
                      TO YOUR REQUEST, PLEASE CALL OUR CLIENT SERVICES
                      DEPARTMENT (1-800-662-2739).
- --------------------------------------------------------------------------------
 
                                       21
<PAGE>   105
 
SELLING BY TELEPHONE  To sell shares by telephone, you or your pre-authorized
                      representative may call our Client Services Department at
                      1-800-662-2739. For telephone redemptions, you may have
                      the proceeds sent to you by mail or by wire. In addition
                      to the details below, please see "Important Information
                      About Telephone Transactions."
 
                      BY MAIL: Telephone mail redemption is automatically
                      established on your account unless you indicate otherwise
                      on your Account Registration Form. You may redeem any
                      amount by calling Vanguard. The proceeds will be paid to
                      the registered shareholders and mailed to the address of
                      record. PLEASE NOTE: As a protection against fraud, your
                      telephone mail redemption privilege will be suspended for
                      15 calendar days following any expedited address change to
                      your account. An expedited address change is one that is
                      made by telephone or in writing, without the signatures of
                      all account owners.
 
                      BY WIRE: Telephone wire redemption must be specifically
                      elected for your account. The best time to elect telephone
                      wire redemption is at the time you complete your Account
                      Registration Form. If you do not presently have telephone
                      wire redemption and wish to establish it, please contact
                      our Client Services Department.
 
                      With the wire redemption option, you may withdraw a
                      minimum of $1,000 and have the amount wired directly to
                      your bank account. Wire redemptions less than $5,000 are
                      subject to a $5 charge deducted by Vanguard. There is no
                      Vanguard charge for wire redemptions of $5,000 or more.
                      However, your bank may assess a separate fee to accept
                      incoming wires.
 
                      A request to change the bank associated with your wire
                      redemption option must be received in writing, signed by
                      each registered shareholder, and accompanied by a voided
                      check or preprinted deposit slip. A signature guarantee is
                      required if your bank registration is not identical to
                      your Vanguard Fund account registration.
- --------------------------------------------------------------------------------
SELLING BY FUND
EXPRESS
Automatic Withdrawal
& Special Redemption  If you select the Fund Express Automatic Withdrawal
                      option, money will be automatically moved from your
                      Vanguard Fund account to your bank account according to
                      the schedule you have selected. The Special Redemption
                      option lets you move money from your Vanguard account to
                      your bank account on an "as needed" basis. To establish
                      these Fund Express options, please provide the appropriate
                      information on the Account Registration Form. We will send
                      you a confirmation of your Fund Express service; please
                      wait two weeks before using the service.
- --------------------------------------------------------------------------------
SELLING BY EXCHANGE   You may sell shares of the Portfolio by making an exchange
                      into another Vanguard Fund account. Please see "Exchanging
                      Your Shares" for details.
- --------------------------------------------------------------------------------
IMPORTANT REDEMPTION
INFORMATION
                      Shares purchased by check or Fund Express may be redeemed
                      at any time. However, your redemption proceeds will not be
                      paid until payment for the purchase is collected, which
                      may take up to ten calendar days.
- --------------------------------------------------------------------------------
DELIVERY OF
REDEMPTION
PROCEEDS
                      Redemption requests received by telephone prior to the
                      close of the Exchange are processed on the day of receipt
                      and the redemption proceeds are normally sent on the
                      following business day.
 
                                       22
<PAGE>   106
 
                      Redemption requests received by telephone after the close
                      of the Exchange are processed on the business day
                      following receipt and the proceeds are normally sent on
                      the second business day following receipt.
 
                      Redemption proceeds must be sent to you within seven days
                      of receipt of your request in Good Order, except as 
                      described above in "Important Redemption Information."
 
                      If you experience difficulty in making a telephone
                      redemption during periods of drastic economic or market
                      changes, your redemption request may be made by regular or
                      express mail. It will be implemented at the net asset
                      value next determined after your request has been received
                      by Vanguard in Good Order. The Fund reserves the right to
                      revise or terminate the telephone redemption privilege at
                      any time.
 
                      The Fund may suspend the redemption right or postpone
                      payment at times when the New York Stock Exchange is
                      closed or under any emergency circumstances as determined
                      by the United States Securities and Exchange Commission.
 
                      If the Board of Directors determines that it would be
                      detrimental to the best interests of the Fund's remaining
                      shareholders to make payment in cash, the Fund may pay
                      redemption proceeds of amounts in excess of $250,000 in
                      whole or in part by a distribution in kind of readily
                      marketable securities.
- --------------------------------------------------------------------------------
VANGUARD'S AVERAGE
COST STATEMENT        If you make a redemption from a qualifying account,
                      Vanguard will send you an Average Cost Statement which
                      provides you with the tax basis of the shares you
                      redeemed. Please see "Statements and Reports" for
                      additional information.
- --------------------------------------------------------------------------------
LOW BALANCE FEE
AND MINIMUM
ACCOUNT BALANCE
REQUIREMENT           Due to the relatively high cost of maintaining smaller
                      accounts, the Portfolio will automatically deduct a $10
                      annual fee in either June or December from non-retirement
                      accounts with balances falling below $2,500 ($500 for
                      Uniform Gifts/Transfers to Minors Act accounts). The fee
                      generally will be waived for investors whose aggregate
                      Vanguard assets exceed $50,000.
 
                      In addition, the Portfolio reserves the right to liquidate
                      any non-retirement account that is below the minimum
                      initial investment amount of $3,000. If at any time your
                      total investment does not have a value of at least $3,000,
                      you may be notified that your account is below the
                      Portfolio's minimum account balance requirement. You would
                      then be allowed 60 days to make an additional investment
                      before the account is liquidated. Proceeds would be
                      promptly paid to the registered shareholder.
 
                      Vanguard will not liquidate your account if it has fallen
                      below $3,000 solely as a result of declining markets,
                      (i.e., a decline in a Portfolio's net asset value).
- --------------------------------------------------------------------------------
EXCHANGING YOUR
SHARES                Should your investment goals change, you may exchange your
                      shares of Vanguard Fixed Income Securities Fund for those
                      of other available Vanguard Funds.
 
IMPORTANT NOTE        A redemption fee of 1% of the value of shares exchanged
                      out will be deducted from the exchange proceeds if shares
                      held for less than one year are exchanged. This fee is
                      paid directly to the Portfolio.
 
                                       23
<PAGE>   107
 
EXCHANGING BY
TELEPHONE
Call Client Services
(1-800-662-2739)      When exchanging shares by telephone, please have ready the
                      Portfolio name, account number, Social Security number or
                      employer identification number listed on the account, and
                      exact name and address in which the account is registered.
                      Only the registered shareholder may complete such an
                      exchange. Requests for telephone exchanges received prior
                      to the close of trading on the Exchange are processed at
                      the close of business that same day. Requests received
                      after the close of the Exchange are processed the next
                      business day. TELEPHONE EXCHANGES ARE NOT ACCEPTED INTO OR
                      FROM NON-RETIREMENT INVESTMENTS IN VANGUARD INDEX TRUST,
                      VANGUARD BALANCED INDEX FUND, VANGUARD INTERNATIONAL
                      EQUITY INDEX FUND, VANGUARD REIT INDEX PORTFOLIO, VANGUARD
                      TOTAL INTERNATIONAL PORTFOLIO, and VANGUARD GROWTH AND
                      INCOME PORTFOLIO. If you experience difficulty in making a
                      telephone exchange, your exchange request may be made by
                      regular or express mail, and it will be implemented at the
                      closing net asset value on the date received by Vanguard,
                      provided the request is received in Good Order.
- --------------------------------------------------------------------------------
EXCHANGING BY MAIL    Please be sure to include on your exchange request the
                      name and account number of your current Portfolio, the
                      name of the Fund you wish to exchange into, the amount you
                      wish to exchange, and the signatures of all registered
                      account holders. Send your request to THE VANGUARD GROUP,
                      VANGUARD FIXED INCOME SECURITIES FUND, P.O. BOX 1120,
                      VALLEY FORGE, PA 19482-1120. (For express or registered
                      mail, send your request to The Vanguard Group, Vanguard
                      Fixed Income Securities Fund, 455 Devon Park Drive, Wayne,
                      PA 19087-1815.)
- --------------------------------------------------------------------------------
EXCHANGING ONLINE     You may use your personal computer to exchange shares of
                      most Vanguard funds by accessing our website
                      (www.vanguard.com). To establish this service for your
                      account, you must first register through the website. We
                      will then send to you, by mail, an account access password
                      that will enable you to make online exchanges.
 
                      The Vanguard funds that you cannot purchase or sell
                      through online exchange are VANGUARD INDEX TRUST, VANGUARD
                      BALANCED INDEX FUND, VANGUARD INTERNATIONAL EQUITY INDEX
                      FUND, VANGUARD REIT INDEX PORTFOLIO, VANGUARD TOTAL
                      INTERNATIONAL PORTFOLIO, and VANGUARD GROWTH AND INCOME
                      PORTFOLIO (formerly known as Vanguard Quantitative
                      Portfolios). These funds do permit online exchanges within
                      IRAs and other retirement accounts.
- --------------------------------------------------------------------------------
IMPORTANT EXCHANGE
INFORMATION
                      Before you make an exchange, you should consider the
                      following:
 
                      - Please read the Fund's prospectus before making an
                        exchange. For a copy and for answers to any questions
                        you may have, call our Investor Information Department
                        (1-800-662-7447).
 
                      - An exchange is treated as a redemption and a purchase.
                        Therefore, you could realize a taxable gain or loss on
                        the transaction.
 
                      - Exchanges by telephone are accepted only if the
                        registrations and the taxpayer identification numbers of
                        the two accounts are identical.
 
                                       24
<PAGE>   108
 
                      - To exchange into an account with a different
                        registration (including a different name, address, or
                        taxpayer identification number), you must provide
                        Vanguard with written instructions that include the
                        guaranteed signatures of all current account owners on
                        your written instructions.
 
   
                      - New accounts are not currently accepted in
                        Vanguard/Windsor Fund, Vanguard/ PRIMECAP Fund or
                        Vanguard Trustees' Equity Fund -- U.S. Portfolio.
    
 
                      - The redemption price of shares redeemed by exchange is
                        the net asset value next determined after Vanguard has
                        received all required documentation in Good Order.
 
                      - When opening a new account by exchange, you must meet
                        the minimum investment requirement of the new Fund.
 
   
                      Every effort will be made to maintain the exchange
                      privilege. However, the Portfolio reserves the right to
                      revise or terminate its provisions, limit the amount of,
                      or reject any exchange, as deemed necessary, at any time.
    
- --------------------------------------------------------------------------------
EXCHANGE
PRIVILEGE
LIMITATIONS           The Portfolio's exchange privilege is not intended to
                      afford shareholders a way to speculate on short-term
                      movements in the market. Accordingly, in order to prevent
                      excessive use of the exchange privilege that may
                      potentially disrupt the management of the Fund and
                      increase transaction costs, the Fund has established a
                      policy of limiting excessive exchange activity.
 
                      Exchange activity will not be deemed excessive if limited
                      to TWO SUBSTANTIVE EXCHANGE REDEMPTIONS (at least 30 days
                      apart) from a Portfolio during any twelve-month period.
                      "Substantive" means either a dollar amount or a series of
                      movements between Vanguard Funds that Vanguard determines,
                      in its sole discretion, could have an adverse impact on
                      the management of the Portfolio. Notwithstanding these
                      limitations, the Portfolio reserves the right to reject
                      any purchase request (including exchange purchases from
                      other Vanguard portfolios) that is reasonably deemed to be
                      disruptive to efficient portfolio management.
- --------------------------------------------------------------------------------
IMPORTANT
INFORMATION ABOUT
TELEPHONE
TRANSACTIONS          The ability to initiate share redemptions (except wire or
                      Fund Express redemptions) and exchanges by telephone is
                      automatically established on your account unless you
                      request in writing that telephone transactions on your
                      account not be permitted. The ability to initiate wire
                      redemptions by telephone will be established on your
                      account only if you specifically elect this option in
                      writing.
 
                      To protect your account from losses resulting from
                      unauthorized or fraudulent telephone instructions,
                      Vanguard adheres to the following security procedures:
 
                      1. SECURITY CHECK.  To request a transaction by telephone,
                         the caller must know (i) the name of the Portfolio;
                         (ii) the 10-digit account number; (iii) the exact name
                         and address used in the registration; and (iv) the
                         Social Security or employer identification number
                         listed on the account.
 
                      2. PAYMENT POLICY.  The proceeds of any telephone
                         redemption by mail will be made payable to the
                         registered shareowner and mailed to the address of
                         record
 
                                       25
<PAGE>   109
 
                        only. In the case of a telephone redemption by wire, the
                        wire will be made only in accordance with the
                        shareowner's prior written instructions.
 
                      Neither the Portfolio nor Vanguard will be responsible for
                      the authenticity of transaction instructions received by
                      telephone, provided that reasonable security procedures
                      have been followed. Vanguard believes that the security
                      procedures described above are reasonable, and that if
                      such procedures are followed, you will bear the risk of
                      any losses resulting from unauthorized or fraudulent
                      telephone transactions on your account.
- --------------------------------------------------------------------------------
TRANSFERRING
REGISTRATION          You may transfer the registration of any of your Portfolio
                      shares to another person by completing a transfer form and
                      sending it to: THE VANGUARD GROUP, ATTENTION: TRANSFER
                      DEPARTMENT, P.O. BOX 1110, VALLEY FORGE, PA 19482-1110.
                      The request must be in Good Order. To receive a transfer
                      form and full instructions, please call our Client
                      Services Department (1-800-662-2739).
- --------------------------------------------------------------------------------
STATEMENTS AND
REPORTS               Vanguard will send you a confirmation statement each time
                      you initiate a transaction in your account except for
                      checkwriting redemptions from Vanguard money market
                      accounts. You will also receive a comprehensive account
                      statement at the end of each calendar quarter. The 
                      fourth-quarter statement will be a year-end statement, 
                      listing all transaction activity for the entire calendar 
                      year.
 
                      Vanguard's Average Cost Statement provides you with the
                      average cost of shares redeemed from your account during
                      the calendar year, using the average cost single category
                      method. This service is available for most taxable
                      accounts opened since January 1, 1986. In general,
                      investors who redeemed shares from a qualifying Vanguard
                      account may expect to receive their Average Cost Statement
                      along with their Portfolio Summary Statement. Please call
                      our Client Services Department (1-800-662-2739) for
                      information.
 
                      Financial reports on the Portfolio will be mailed to you
                      semiannually, according to the Portfolio's fiscal
                      year-end. To keep the Portfolio's costs as low as possible
                      (so that you and other shareholders can keep more of the
                      Fund's investment earnings), Vanguard attempts to
                      eliminate duplicate mailings to the same address. When we
                      find that two or more Portfolio shareholders have the same
                      last name and address, we send just one Portfolio report
                      to that address -- instead of mailing separate reports to
                      each shareholder. If you want us to send separate reports,
                      however, you may notify our Investor Information
                      Department at 1-800-662-7447.
- --------------------------------------------------------------------------------
OTHER VANGUARD
SERVICES              For more information about any of these services, please
                      call our Investor Information Department at
                      1-800-662-7447.
 
VANGUARD DIRECT
DEPOSIT SERVICE
                      With Vanguard's Direct Deposit Service, most U.S.
                      Government checks (including Social Security and military
                      pension checks) and private payroll checks may be
                      automatically deposited into your Vanguard Fund account.
                      Separate brochures and forms are available for direct
                      deposit of U.S. Government and private payroll checks.
 
VANGUARD AUTOMATIC
EXCHANGE SERVICE      Vanguard's Automatic Exchange Service allows you to move
                      money automatically among your Vanguard Fund accounts. For
                      instance, the service can be used to
 
                                       26
<PAGE>   110
 
                      "dollar cost average" from a money market portfolio into a
                      stock or bond fund or to contribute to an IRA or other
                      retirement plan. Please contact our Client Services
                      Department at 1-800-662-2739 for additional information.
 
VANGUARD FUND
EXPRESS
                      Vanguard's Fund Express allows you to transfer money
                      between your Portfolio account and your account at a bank,
                      savings and loan association, or a credit union that is a
                      member of the Automated Clearing House (ACH) system. You
                      may elect this service on the Account Registration Form or
                      call our Investor Information Department (1-800-662-7447)
                      for a Fund Express application.
 
                      Special rules govern how your Fund Express purchases or
                      redemptions are credited to your account. In addition,
                      some services of Fund Express cannot be used with specific
                      Vanguard Funds. For more information, please refer to the
                      Vanguard Fund Express brochure.
 
VANGUARD DIVIDEND
EXPRESS
                      Vanguard's Dividend Express allows you to transfer your
                      dividend and/or capital gains distributions automatically
                      from your Portfolio account, one business day after the
                      Fund's payable date, to your account at a bank, savings
                      and loan association, or a credit union that is a member
                      of the Automated Clearing House (ACH) system. You may
                      elect this service on the Account Registration Form or
                      call the Investor Information Department (1-800-662-7447)
                      for a Vanguard Dividend Express application.
 
VANGUARD
TELE-ACCOUNT(R)
                      Vanguard's Tele-Account is a convenient, automated service
                      that provides share price, price change and yield
                      quotations on Vanguard Funds through any TouchTone(TM)
                      telephone. This service also lets you obtain information
                      about your account balance, your last transaction, and
                      your most recent dividend or capital gains payment. In
                      addition, you may perform investment exchanges of Vanguard
                      Fund shares and redemptions by check using Tele-Account.
                      To contact Vanguard's Tele-Account service, dial
                      1-800-ON-BOARD (1-800-662-6273). A brochure offering
                      detailed operating instructions is available from our
                      Investor Information Department (1-800-662-7447).
 
COMPUTER ACCESS
 
VANGUARD ONLINE
www.vanguard.com      Use your personal computer to learn more about Vanguard's
                      funds and services; keep in touch with your Vanguard
                      accounts; map out a long-term investment strategy;
                      initiate certain transactions; and ask questions, make
                      suggestions, and send messages to Vanguard.
 
                      Our education-oriented website provides timely news and
                      information about Vanguard's funds and services; an online
                      "university" that offers a variety of mutual fund classes;
                      and easy-to-use, interactive tools to help you create your
                      own investment and retirement strategies.
- --------------------------------------------------------------------------------
 
                                       27
<PAGE>   111
 
                      [THIS PAGE INTENTIONALLY LEFT BLANK]
<PAGE>   112
 
- --------------------------------------------------------------------------------
 
<TABLE>
<S>       <C>                             <C>
          [Vanguard
          Logo]
          ---------------------------
          THE VANGUARD GROUP
          P.O. Box 2600
          Valley Forge, PA 19482
          INVESTOR INFORMATION
          DEPARTMENT:
          1-800-662-7447 (SHIP)
          CLIENT SERVICES
          DEPARTMENT:
          1-800-662-2739 (CREW)
          TELE-ACCOUNT FOR
          24-HOUR ACCESS:
          1-800-662-6273 (ON-BOARD)
          TELECOMMUNICATION SERVICE
          FOR THE HEARING-IMPAIRED:
          1-800-662-2738
          TRANSFER AGENT:
          The Vanguard Group, Inc.
          P.O. Box 2600
          Valley Forge, PA 19482
          P029
- -------------------------------------------------------------------------------
 
<CAPTION>
<S>        <C>
                                   [Flag Logo]
                              [Vanguard      Logo]
                          P  R  O  S  P  E  C  T  U  S
                                  MAY 29, 1998
                                 [Vanguard Logo]
- -------------------------------------------------------------------------------
</TABLE>
<PAGE>   113
 
- --------------------------------------------------------------------------------
 
                                                       [FLAG LOGO]
 
                                                     [VANGUARD LOGO]
                                             P   R  O  S  P  E  C  T  U  S
 
                                                      MAY 29, 1998
 
                                                [THE VANGUARD GROUP LOGO]
 
- --------------------------------------------------------------------------------
<PAGE>   114
 
================================================================================
 
[VANGUARD LOGO]                                   A Member of The Vanguard Group
================================================================================
 
PROSPECTUS -- MAY 29, 1998
- --------------------------------------------------------------------------------
 
FUND INFORMATION: INSTITUTIONAL INVESTOR SERVICES -- 1-800-523-1036; PARTICIPANT
SERVICES -- 1-800-523-1188
- --------------------------------------------------------------------------------
 
INVESTMENT
OBJECTIVE
AND POLICIES          Vanguard Fixed Income Securities Fund, Inc. (the "Fund")
                      is an open-end diversified investment company that
                      consists of nine Portfolios. This prospectus pertains only
                      to the Fund's Short-Term Corporate Portfolio (the
                      "Portfolio"). The objective of the Portfolio is to provide
                      investors with a high level of income consistent with the
                      maintenance of principal and liquidity by investing in
                      investment grade fixed income securities with an average
                      maturity of one to three years. There is no assurance that
                      the Portfolio will achieve its stated objective. Shares of
                      the Portfolio are neither insured nor guaranteed by any
                      agency of the U.S. Government, including the FDIC.
- --------------------------------------------------------------------------------
 
INVESTMENT
ALTERNATIVES          The Portfolio offers two separate classes of shares to
                      investors. The Portfolio's "Institutional Shares" are
                      designed primarily for investors who meet a minimum
                      initial investment of $50 million and generally do not
                      require special employee benefit plan services. Only the
                      Institutional Shares are offered through this prospectus;
                      the Portfolio's other class of shares, the "Investor
                      Shares," are offered through a separate prospectus. To
                      obtain information on the Investor Shares, please call
                      1-800-523-1036. The Portfolio's separate share classes
                      have different expenses; as a result, their investment
                      performance will vary.
- --------------------------------------------------------------------------------
 
OPENING AN
ACCOUNT               Shares of the Portfolio may be purchased by Federal Funds
                      wire. The minimum initial investment is $50 million.
- --------------------------------------------------------------------------------
 
ABOUT THIS
PROSPECTUS            This Prospectus is designed to set forth concisely the
                      information you should know about the Portfolio before you
                      invest. It should be retained for future reference. A
                      "Statement of Additional Information" containing
                      additional information about the Portfolio has been filed
                      with the Securities and Exchange Commission. This
                      Statement is dated May 29, 1998 and has been incorporated
                      by reference into this Prospectus. A copy may be obtained
                      without charge by writing to the Portfolio, calling our
                      Participant Services Department at 1-800-523-1188, or
                      visiting the Securities and Exchange Commission's website
                      (www.sec.gov).
- --------------------------------------------------------------------------------
 
TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                  Page
<S>                               <C>
Portfolio Expenses...............   2
Financial Highlights.............   3
Yield and Total Return...........   4
FUND INFORMATION
Investment Objective.............   5
Investment Policies..............   5
</TABLE>
 
<TABLE>
<CAPTION>
                                  Page
<S>                               <C>
Investment Risks.................   6
Who Should Invest................   7
Implementation of Policies.......   8
Investment Limitations...........  12
Management of the Portfolio......  12
Investment Adviser...............  13
</TABLE>
 
<TABLE>
<CAPTION>
                                  Page
<S>                               <C>
Dividends, Capital Gains
  and Taxes......................  14
The Share Price of
  The Portfolio..................  15
General Information..............  16
Shareholder Guide................  17
</TABLE>
 
- --------------------------------------------------------------------------------
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION, NOR HAS THE SECURITIES AND EXCHANGE COMMISSION PASSED UPON
THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY
IS A CRIMINAL OFFENSE.
- --------------------------------------------------------------------------------
<PAGE>   115
 
PORTFOLIO EXPENSES    The following table illustrates ALL expenses and fees that
                      you would incur as a shareholder of each share class of
                      the Short-Term Corporate Portfolio. These expenses and
                      fees are based upon those incurred during the fiscal year
                      ended January 31, 1998.
 
<TABLE>
<CAPTION>
                                                                                   INVESTOR     INSTITUTIONAL
                                                                                   SHARES OF      SHARES OF
                                                                                  SHORT-TERM      SHORT-TERM
                                                                                   CORPORATE      CORPORATE
                                       SHAREHOLDER TRANSACTION EXPENSES            PORTFOLIO      PORTFOLIO
                               -------------------------------------------------------------------------------
                               <S>                                                <C>           <C>
                               Sales Load Imposed on Purchases.................      None            None
                               Sales Load Imposed on Reinvested Dividends......      None            None
                               Redemption Fees*................................      None            None
                               Exchange Fees...................................      None            None
</TABLE>
 
<TABLE>
<CAPTION>
                                                                                   INVESTOR     INSTITUTIONAL
                                                                                   SHARES OF      SHARES OF
                                                                                  SHORT-TERM      SHORT-TERM
                                                                                   CORPORATE      CORPORATE
                                        ANNUAL FUND OPERATING EXPENSES             PORTFOLIO      PORTFOLIO
                               -------------------------------------------------------------------------------
                               <S>                                                <C>           <C>
                               Management & Administrative Expenses............      0.23%           0.13%
                               Investment Advisory Fees........................      0.01            0.01
                               12b-1 Fees......................................      None            None
                               Other Expenses
                                 Distribution Costs............................      0.03%           0.01%
                                 Miscellaneous Expenses........................      0.01            0.00
                                                                                  ----------    -----------
                               Total Other Expenses............................      0.04            0.01
                                                                                  ----------    -----------
                                         TOTAL OPERATING EXPENSES..............      0.28%           0.15%
                                                                                  ==========    ===========
</TABLE>
 
                      * Wire redemptions of less than $5,000 are subject to a $5
                      processing fee.
 
                      The purpose of this table is to assist you in
                      understanding the various costs and expenses that you
                      would bear directly or indirectly as an investor in the
                      Portfolio.
 
                      The following example illustrates the expenses that you
                      would incur on a $1,000 investment over various periods,
                      assuming (1) a 5% annual rate of return and (2) redemption
                      at the end of each period.
 
<TABLE>
<CAPTION>
                                                                         1 YEAR   3 YEARS   5 YEARS   10 YEARS
                                                                         ------   -------   -------   --------
                               <S>                                       <C>      <C>       <C>       <C>
                               Short-Term Corporate
                                 Portfolio - Investor Shares..........     $3       $9        $16       $36
                               Short-Term Corporate
                                 Portfolio - Institutional Shares.....     $2       $5        $ 8       $19
</TABLE>
 
                      THIS EXAMPLE SHOULD NOT BE CONSIDERED A REPRESENTATION OF
                      PAST OR FUTURE EXPENSES OR PERFORMANCE. ACTUAL EXPENSES
                      MAY BE HIGHER OR LOWER THAN THOSE SHOWN.
- --------------------------------------------------------------------------------
 
                                        2
<PAGE>   116
 
FINANCIAL
HIGHLIGHTS            The following financial highlights for a share outstanding
                      throughout each period have been derived from financial
                      statements which were audited by Price Waterhouse LLP,
                      independent accountants, whose reports on the financial
                      statements which contain this information were
                      unqualified. This information should be read in
                      conjunction with the Portfolio's financial statements and
                      notes thereto, which, together with the remaining portions
                      of the Fund's 1998 Annual Report to Shareholders, are
                      incorporated by reference in the Statement of Additional
                      Information and in this Prospectus, and which appear,
                      along with the reports of Price Waterhouse LLP, in the
                      Fund's 1998 Annual Report to Shareholders. For a more
                      complete discussion of the Fund's performance, please see
                      the Fund's 1998 Annual Report to Shareholders which may be
                      obtained without charge by writing to the Fund or by
                      calling our Investor Information Department at
                      1-800-662-7447.
 
   
<TABLE>
<CAPTION>
                                     -------------------------------------------------------------------------------------------
                                                          SHORT-TERM CORPORATE PORTFOLIO -- INVESTOR SHARES
                                     -------------------------------------------------------------------------------------------
                                                                       YEAR ENDED JANUARY 31,
                                     -------------------------------------------------------------------------------------------
                                      1998     1997     1996     1995     1994     1993     1992     1991     1990     1989
<S>                                  <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>    <C>
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF
  YEAR.............................  $10.75   $10.94   $10.40   $10.94   $10.99   $10.88   $10.50   $10.34   $10.23   $10.43
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
INVESTMENT OPERATIONS
  Net Investment Income............    .664     .663     .671     .596     .605     .695     .804     .876     .895     .833
  Net Realized and Unrealized Gain
    (Loss) on Investments..........    .120    (.190)    .540    (.540)    .049     .275     .380     .160     .110    (.200)
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL FROM INVESTMENT
      OPERATIONS...................    .784     .473    1.211     .056     .654     .970    1.184    1.036    1.005     .633
- --------------------------------------------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net
    Investment Income..............   (.664)   (.663)   (.671)   (.596)   (.605)   (.695)   (.804)   (.876)   (.895)   (.833)
  Distributions from Realized
    Capital Gains..................      --       --       --       --    (.099)   (.165)      --       --       --       --
                                     ------   ------   ------   ------   ------   ------   ------   ------   ------   ------
    TOTAL DISTRIBUTIONS............   (.664)   (.663)   (.671)   (.596)   (.704)   (.860)   (.804)   (.876)   (.895)   (.833)
- --------------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF YEAR.......  $10.87   $10.75   $10.94   $10.40   $10.94   $10.99   $10.88   $10.50   $10.34   $10.23
================================================================================================================================
TOTAL RETURN.......................    7.53%    4.52%   11.95%    0.60%    6.11%    9.29%   11.70%   10.47%   10.18%    6.31%
================================================================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Year
  (Millions).......................  $4,709   $4,531   $3,873   $2,924   $3,573   $2,811   $1,911     $829     $597     $493
Ratio of Total Expenses to Average
  Net Assets.......................    0.28%    0.25%    0.27%    0.28%    0.26%    0.27%    0.26%    0.31%    0.28%    0.34%
Ratio of Net Investment Income to
  Average Net Assets...............    6.17%    6.18%    6.23%    5.66%    5.48%    6.33%    7.44%    8.48%    8.70%    8.17%
Portfolio Turnover Rate............      45%      45%      62%      69%      61%      71%      99%     107%     121%     165%
</TABLE>
    
 
                                        3
<PAGE>   117
 
   
<TABLE>
<CAPTION>
                                                              ---------------------------------
                                                              SHORT-TERM CORPORATE PORTFOLIO --
                                                              INSTITUTIONAL SHARES
                                                              ---------------------------------
                                                                    SEPTEMBER 30, 1997,+
                                                                     TO JANUARY 31, 1998
<S>                                                           <C>
- -----------------------------------------------------------------------------------------------
NET ASSET VALUE, BEGINNING OF PERIOD........................               $10.80
                                                              --------------------
INVESTMENT OPERATIONS
  Net Investment Income.....................................                 .229
  Net Realized and Unrealized Gain (Loss) on Investments....                 .070
                                                              --------------------
    TOTAL FROM INVESTMENT OPERATIONS........................                 .299
- -----------------------------------------------------------------------------------------------
DISTRIBUTIONS
  Dividends from Net Investment Income......................                (.229)
  Distributions from Realized Capital Gains.................                   --
                                                              --------------------
    TOTAL DISTRIBUTIONS.....................................                (.229)
- -----------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD..............................               $10.87
===============================================================================================
TOTAL RETURN................................................                 2.79%
===============================================================================================
RATIOS/SUPPLEMENTAL DATA
Net Assets, End of Period (Millions)........................               $263
Ratio of Total Expenses to Average Net Assets...............                 0.15%*
Ratio of Net Investment Income to Average Net Assets........                 6.28%*
Portfolio Turnover Rate.....................................                   45%
+ Inception.
* Annualized.
- -----------------------------------------------------------------------------------------------
</TABLE>
    
 
YIELD AND
TOTAL RETURN          From time to time each share class of the Portfolio may
                      advertise its yield and total return. Both yield and total
                      return figures are based on historical earnings and are
                      not intended to indicate future performance. The "total
                      return" of a class of shares of the Portfolio refers to
                      the average annual compounded rates of return over one- ,
                      five- and ten-year periods or for the life of the class of
                      shares of the Portfolio (as stated in the advertisement)
                      that would equate an initial amount invested at the
                      beginning of a stated period to the ending redeemable
                      value of the investment, assuming the reinvestment of all
                      dividends and capital gains distributions. The investment
                      results of each class of shares of the Portfolio will vary
                      due to their different expenses.
 
                      In accordance with industry guidelines set forth by the
                      U.S. Securities and Exchange Commission, the "30-day
                      yield" of each share class of the Portfolio is calculated
                      by dividing net investment income per share earned during
                      a 30-day period by the net asset value per share on the
                      last day of the period. Net investment income includes
                      interest and dividend income per share earned by the class
                      of shares; it is net of all expenses and all recurring and
                      nonrecurring charges that have been applied to all
                      shareholder accounts of that class. The yield calculation
                      assumes that net investment income earned over 30 days is
                      compounded monthly for six months and then annualized.
                      Methods used to calculate advertised yields are
                      standardized for all stock and bond mutual funds. However,
                      these methods differ from the accounting methods used by
                      the Portfolio to maintain its books and records, and so
                      the advertised 30-day yield may not fully reflect the
                      income paid to an investor's account or the yield reported
                      in the Portfolio's Reports to Shareholders.
 
                                        4
<PAGE>   118
 
                      Additionally, the Portfolio may compare its performance to
                      that of the Lehman Aggregate Bond Index, and may advertise
                      its duration, a measure of a Portfolio's sensitivity to
                      interest rate changes.
- --------------------------------------------------------------------------------
 
INVESTMENT
OBJECTIVE
THE PORTFOLIO SEEKS TO
PROVIDE A HIGH LEVEL
OF CURRENT INCOME     The Short-Term Corporate Portfolio is part of Vanguard
                      Fixed Income Securities Fund, a no-load, open-end,
                      diversified investment company that seeks to provide
                      investors with a high level of income consistent with the
                      maintenance of principal and liquidity.
 
                      The Portfolio seeks to achieve this objective by investing
                      in investment-grade fixed income securities and by
                      maintaining an average maturity of one to three years.
                      There is no assurance that the Portfolio will achieve its
                      stated objective.
 
                      The investment objective of the Portfolio is not
                      fundamental and so may be changed by the Board of
                      Directors without shareholder approval. Any such change
                      could result in the Portfolio having investment objectives
                      different from the objectives which a shareholder
                      considered appropriate at the time of investment in the
                      Portfolio. However, shareholders would be notified prior
                      to any material change in the Portfolio's objective.
- --------------------------------------------------------------------------------
 
INVESTMENT
POLICIES              The SHORT-TERM CORPORATE PORTFOLIO invests in the
                      following investment grade fixed income securities:
 
                      (1) Short-term and intermediate-term corporate debt
                          securities;
 
                      (2) U.S. Treasury and U.S. Government agency obligations;
 
                      (3) Obligations issued by state and municipal governments
                          and their agencies and instrumentalities;
 
                      (4) Bank obligations, including certificates of deposit
                          and bankers' acceptances;
 
                      (5) Commercial paper; and
 
                      (6) Repurchase agreements collateralized by these
                          securities.
 
                      Investment grade corporate debt securities are those rated
                      a minimum of Baa3 by Moody's Investors Service, Inc.
                      ("Moody's") or BBB- by Standard & Poor's Corporation
                      ("Standard & Poor's"). Investment grade commercial paper
                      is rated A-1 or better by Standard & Poor's or Prime-1 by
                      Moody's, or, if unrated, issued by a corporation having an
                      outstanding unsecured debt issue rated A or better by
                      Moody's or Standard & Poor's. At least 70% of the
                      Short-Term Corporate Portfolio's assets will be invested
                      in debt securities rated a minimum of A3 by Moody's or A-
                      by Standard & Poor's, and not more than 30% of the
                      Portfolio's assets may be invested in debt securities
                      rated Baa by Moody's or BBB by Standard & Poor's.
                      Securities rated Baa or BBB are considered medium grade
                      obligations. Interest payments and principal are regarded
                      as adequate for the present, but certain protective
                      elements found in higher rated bonds may be lacking. Such
                      bonds lack outstanding investment characteristics and have
                      speculative characteristics.
 
                                        5
<PAGE>   119
 
                      In the event that a security held by the Portfolio is
                      downgraded, the Portfolio may continue to hold such
                      security until such time as the adviser deems it
                      advantageous to dispose of the security.
 
                      In an effort to minimize fluctuations in market value, the
                      Short-Term Corporate Portfolio is expected to maintain a
                      dollar-weighted average maturity between 1 and 3 years.
                      The Short-Term Corporate Portfolio may also hold
                      asset-backed securities, as well as securities of foreign
                      issuers provided such securities are denominated in U.S.
                      dollars. In addition, the Portfolio may invest in bond
                      (interest rate) futures and options to a limited extent.
                      See "Implementation of Policies" for a description of
                      these investment practices of the Portfolio.
 
                      The Portfolio is managed without regard to tax
                      ramifications, and is responsible for voting the shares of
                      all securities it holds.
- --------------------------------------------------------------------------------
 
INVESTMENT RISKS
THE PORTFOLIO IS
SUBJECT PRIMARILY
TO INTEREST RATE,
INCOME, CREDIT AND
MANAGER RISK          As a mutual fund investing in fixed income securities, the
                      Portfolio is subject primarily to interest rate, income,
                      credit and manager risk. INTEREST RATE RISK is the
                      potential for a decline in bond prices due to rising
                      interest rates. In general, bond prices vary inversely
                      with interest rates. When interest rates rise, bond prices
                      generally fall. Conversely, when interest rates fall, bond
                      prices generally rise. The change in price depends on
                      several factors, including the bond's maturity date. In
                      general, bonds with longer maturities are more sensitive
                      to changes in interest rates than bonds with shorter
                      maturities.
 
                      These principles of interest rate risk also apply to U.S.
                      Treasury and U.S. Government agency securities. As with
                      other bond investments, U.S. Government securities will
                      rise and fall in value as interest rates change. A
                      SECURITY BACKED BY THE U.S. TREASURY OR THE FULL FAITH AND
                      CREDIT OF THE UNITED STATES IS GUARANTEED ONLY AS TO THE
                      TIMELY PAYMENT OF INTEREST AND PRINCIPAL WHEN HELD TO
                      MATURITY. THE CURRENT MARKET PRICES FOR SUCH SECURITIES
                      ARE NOT GUARANTEED AND WILL FLUCTUATE.
 
                      As an illustration of interest rate risk, the charts below
                      depict the effect of a one and two percentage point change
                      in interest rates on three bonds of varying maturities:
 
                       PERCENT CHANGE IN THE PRICE OF A PAR BOND YIELDING 7.5%
 
<TABLE>
<CAPTION>
                                                                 1 PERCENTAGE POINT   1 PERCENTAGE POINT
                                                                    INCREASE IN          DECREASE IN
                                       STATED MATURITY             INTEREST RATES       INTEREST RATES
                               -------------------------------   ------------------   ------------------
                               <S>                               <C>                  <C>
                               Short-Term (2.5 years)                  - 2.2%                + 2.3%
                               Intermediate-Term (10 years)            - 6.6%                + 7.3%
                               Long-Term (20 years)                    - 9.5%                +11.1%
</TABLE>
 
<TABLE>
<CAPTION>
                                                                 2 PERCENTAGE POINT   2 PERCENTAGE POINT
                                                                    INCREASE IN          DECREASE IN
                                       STATED MATURITY             INTEREST RATES       INTEREST RATES
                               -------------------------------   ------------------   ------------------
                               <S>                               <C>                  <C>
                               Short-Term (2.5 years)                  - 4.3%                + 4.6%
                               Intermediate-Term (10 years)            -12.7%                +15.2%
                               Long-Term (20 years)                    -17.8%                +24.1%
</TABLE>
 
                                        6
<PAGE>   120
 
                      These charts are intended to provide you with guidelines
                      for determining the degree of interest rate risk you may
                      be willing to assume. The yield and price changes shown
                      should not be taken as representative of the Portfolio's
                      current or future yield or expected changes in the
                      Portfolio's share price.
 
                      INCOME RISK is the potential for a decline in the
                      Portfolio's income due to falling market interest rates.
                      In relative terms, income risk will be higher for the
                      Fund's shorter-term Portfolios and lower for the Fund's
                      longer-term Portfolios.
 
                      The Portfolio is also subject to credit risk. CREDIT RISK,
                      also known as default risk, is the possibility that a bond
                      issuer will fail to make timely payments of interest or
                      principal to the Portfolio. The credit risk of the
                      Portfolio depends on the quality of its investments.
                      Reflecting their higher risks, lower-quality bonds
                      generally offer higher yields (all other factors being
                      equal).
 
   
                      Finally, the investment adviser manages the Portfolio
                      according to the traditional methods of "active"
                      investment management, which involve the buying and
                      selling of securities based upon economic, financial and
                      market analysis and investment judgment. MANAGER RISK
                      refers to the possibility that the Portfolio's investment
                      adviser may fail to execute the Portfolio's investment
                      strategy effectively. As a result, the Portfolio may fail
                      to achieve its stated objective.
    
 
THE PORTFOLIO PROVIDES
MODERATE EXPOSURE TO
INTEREST RATE RISK    Interest rate risk for the SHORT-TERM CORPORATE PORTFOLIO
                      should be modest. Because of its short-term average
                      weighted maturity, the Portfolio is expected to exhibit
                      low to moderate price fluctuations as interest rates
                      change.
 
THE PORTFOLIO PROVIDES
LOW EXPOSURE TO CREDIT
RISK                  With its well diversified corporate bond holdings and its
                      emphasis on high-quality bonds, overall credit risk should
                      be quite low.
- --------------------------------------------------------------------------------
 
WHO SHOULD
INVEST
INVESTORS SEEKING
CURRENT INCOME        The Portfolio is intended for investors who are seeking a
                      high level of current income from their investments. The
                      Portfolio is also suitable for investors with common stock
                      holdings who are seeking a complementary fixed income
                      investment to create a more diversified and balanced
                      investment mix. Because of potential fluctuations in its
                      share price, the Portfolio may be inappropriate for
                      short-term investors who require maximum stability of
                      principal. Because of the risks associated with bond
                      investments, the Portfolio is intended to be a long-term
                      investment vehicle and is not designed to provide
                      investors with a means of speculating on short-term bond
                      market movements.
 
                      Investors who engage in excessive account activity
                      generate additional costs which are borne by all of the
                      Portfolio's shareholders. In order to minimize such costs
                      the Portfolio has adopted the following policies. The
                      Portfolio reserves the right to reject any purchase
                      request (including exchange purchases from other Vanguard
                      portfolios) that is reasonably deemed to be disruptive to
                      efficient portfolio management, either because of the
                      timing of the investment or previous excessive trading by
                      the investor. Additionally, the Portfolio has adopted
                      exchange privilege limitations as described in the section
                      "Exchange Privilege Limitations." Finally, the Portfolio
                      reserves the right to suspend the offering of its shares.
 
                                        7
<PAGE>   121
 
                      You should base your selection of the Portfolio on your
                      own objectives, risk preferences, and time horizon.
 
   
                      The Short-Term Corporate Portfolio is designed for
                      investors who are seeking yields that are more durable and
                      usually higher than those available from money market
                      funds, and who can tolerate modest fluctuations in the
                      value of their investment.
    
- --------------------------------------------------------------------------------
IMPLEMENTATION
OF POLICIES
THE PORTFOLIO MAY
INVEST IN REPURCHASE
AGREEMENTS            The Portfolio utilizes a variety of investment practices
                      in pursuit of its objective.
 
   
                      The Portfolio may invest in repurchase agreements
                      according to the restrictions and limitations set forth in
                      "Investment Policies." A repurchase agreement is a means
                      of investing monies for a short period. In a repurchase
                      agreement, a seller -- a U.S. commercial bank or
                      recognized U.S. securities dealer -- sells securities to a
                      Portfolio and agrees to repurchase the securities at the
                      Portfolio's cost plus interest within a specified period
                      (normally one day). In these transactions, the securities
                      purchased by the Portfolio will have a total value equal
                      to or in excess of the value of the repurchase agreement,
                      and will be held by the Portfolio's Custodian Bank until
                      repurchased.
    
 
                      The use of repurchase agreements involves certain risks.
                      For example, if the other party to the agreement defaults
                      on its obligation to repurchase the underlying security at
                      a time when the value of the security has declined, the
                      Portfolio may incur a loss upon disposition of the
                      security. If the other party to the agreement becomes
                      insolvent and subject to liquidation or reorganization
                      under the Bankruptcy Code or other laws, a court may
                      determine that the underlying security is collateral for a
                      loan by the Portfolio and not within the control of the
                      Portfolio. As a result, the Portfolio's ability to realize
                      on such collateral may be automatically stayed. Finally,
                      it is possible that the Portfolio may not be able to
                      substantiate its interest in the underlying security and
                      may be deemed an unsecured creditor of the other party to
                      the agreement. While the Portfolio's management
                      acknowledges these risks, it is expected that they can be
                      controlled through careful monitoring procedures.
 
THE PORTFOLIO MAY
OWN RESTRICTED OR
ILLIQUID SECURITIES   The Portfolio may own restricted or illiquid securities to
                      a limited extent. Restricted or illiquid securities are
                      securities which are not freely marketable or which are
                      subject to restrictions upon sale under the Securities Act
                      of 1933. The Portfolio may invest up to 15% of its net
                      assets in restricted or illiquid securities. The Fund's
                      Board of Directors may from time to time determine certain
                      restricted securities known as Rule 144A securities to be
                      liquid. Such securities will not be subject to the 15%
                      limitation described above.
 
THE PORTFOLIO MAY
INVEST IN SECURITIES
OF FOREIGN ISSUERS    The Short-Term Corporate Portfolio may hold securities of
                      foreign issuers, but all such securities must be
                      denominated in U.S. dollars. Securities of foreign issuers
                      may trade in U.S. or foreign securities markets.
                      Securities of foreign issuers may involve investment risks
                      that are different from those of domestic issuers. Such
                      risks include the effect of foreign economic policies and
                      conditions, future political and economic developments,
                      and the possible imposition of exchange controls or other
                      foreign governmental restrictions on foreign debt issuers.
                      There may also be
 
                                        8
<PAGE>   122
 
                      less publicly available information about a foreign issuer
                      than a domestic issuer of securities. Foreign issuers are
                      generally not subject to the uniform accounting, auditing
                      and financial reporting standards that apply to domestic
                      issuers. Also, foreign debt markets may be characterized
                      by lower liquidity, greater price volatility, and higher
                      transaction costs. Additionally, it may be difficult to
                      obtain or enforce a legal judgment in a foreign court.
 
THE PORTFOLIO MAY
INVEST IN FUTURES
CONTRACTS, OPTIONS,
AND OTHER DERIVATIVE
SECURITIES            The Portfolio may invest in futures contracts and options
                      to a limited extent. Specifically, the Portfolio may enter
                      into futures contracts provided that not more than 5% of
                      its assets are required as a futures contract margin
                      deposit; in addition, the Portfolio may enter into futures
                      contracts and options transactions only to the extent that
                      obligations under such contracts or transactions represent
                      not more than 20% of the Portfolio's assets.
 
                      Futures contracts and options may be used for several
                      reasons: to maintain cash reserves while simulating full
                      investment, to facilitate trading, to reduce transaction
                      costs, or to seek higher investment returns when a
                      specific futures contract is priced more attractively than
                      other futures contracts or the underlying security or
                      index. The Portfolio intends to use futures contracts only
                      for bona fide hedging purposes and will not use futures
                      contracts or options for speculative purposes.
 
FUTURES CONTRACTS
AND OPTIONS POSE
CERTAIN RISKS         The primary risks associated with the use of futures
                      contracts and options are: (i) imperfect correlation
                      between the change in market value of the bonds held by a
                      Portfolio and the prices of futures contracts and options;
                      and (ii) possible lack of a liquid secondary market for a
                      futures contract and the resulting inability to close a
                      futures position prior to its maturity date. The risk of
                      imperfect correlation will be minimized by investing only
                      in those contracts whose price fluctuations are expected
                      to resemble those of the Portfolio's underlying
                      securities. The risk that a Portfolio will be unable to
                      close out a futures position will be minimized by entering
                      into such transactions on a national exchange with an
                      active and liquid secondary market.
 
                      The risk of loss in trading futures contracts in some
                      strategies can be substantial, due both to the low margin
                      deposits required and the extremely high degree of
                      leverage involved in futures pricing. As a result, a
                      relatively small price movement in a futures contract may
                      result in immediate and substantial loss (or gain) to the
                      investor. When investing in futures contracts, a Portfolio
                      will segregate cash or other liquid portfolio securities
                      in the amount of the underlying obligation.
 
DERIVATIVE INVESTING  Derivatives are instruments whose value is linked to or
                      derived from an underlying security or index. The most
                      common are futures and options which are described above.
                      Other derivatives include swaps, inverse floaters, IO's
                      (interest only), and PO's (principal only). Derivatives
                      may be traded separately on exchanges or in the
                      over-the-counter market, or they may be imbedded in other
                      securities. The most common imbedded derivative is the
                      call option attached to or imbedded in a callable
                      government or callable corporate bond. The owner of a
                      traditional callable bond holds a combination of a long
                      position in a non-callable bond and a short position in a
                      call option on that bond, i.e. the bond issuer has the
                      right to call the bond away from the holder of the bond.
                      Any of these instruments may also be used individually
 
                                        9
<PAGE>   123
 
                      or in combination to hedge against unfavorable changes in
                      interest rates, or to speculate on anticipated changes in
                      interest rates. Derivatives may be structured with no or a
                      high degree of leverage. When derivatives are used as
                      hedges, the risk incurred is that the derivative
                      instrument's value may change differently than the value
                      of the security being hedged. This "basis risk" is
                      generally lower than the risk associated with an unhedged
                      position in the security being hedged. Some derivatives
                      may entail liquidity risk, i.e. the risk that the
                      instrument cannot be sold at a reasonable price in highly
                      volatile markets. Leveraged derivatives used for
                      speculation are very volatile, and therefore, very risky.
                      However, the Portfolio will only utilize derivatives for
                      hedging or arbitrage purposes, and not for speculative
                      purposes. Over-the-counter derivatives involve a
                      counterparty risk, i.e. the risk that the individual or
                      institution on the other side of the agreement will not or
                      cannot meet its obligations under the derivative
                      agreement.
 
THE PORTFOLIO MAY LEND
ITS SECURITIES        The Portfolio may lend its investment securities to
                      qualified institutional investors for either short-term or
                      long-term purposes of realizing additional income. Loans
                      of securities by the Portfolio will be collateralized by
                      cash, letters of credit, or securities issued or
                      guaranteed by the U.S. Government or its agencies. The
                      collateral will equal at least 100% of the current market
                      value of the loaned securities, and such loans may not
                      exceed 33 1/3% of the value of the Portfolio's total
                      assets (including any collateral obtained in connection
                      with such loans).
 
THE PORTFOLIO MAY
INVEST IN CMOS        The Short-Term Corporate Portfolio may invest in
                      collateralized mortgage obligations (CMOs), bonds that are
                      collateralized by whole loan mortgages or mortgage
                      pass-through securities. The Portfolio may also purchase
                      CMO's issued by agencies or instrumentalities of the U.S.
                      Government and privately-issued CMOs carrying investment
                      grade ratings. The bonds issued under a CMO structure are
                      divided into groups with varying maturities, and the cash
                      flows generated by the mortgages or mortgage pass-through
                      securities in the collateral pool are used to first pay
                      interest and then pay principal to the CMO bondholders.
                      Under the CMO structure, the repayment of principal among
                      the different groups is prioritized in accordance with the
                      terms of the particular CMO issuance. The "fastest-pay"
                      group of bonds, as specified in the prospectus for the
                      issuance, would initially receive all principal payments.
                      When that group of bonds is retired, the next group or
                      groups, in the sequence, as specified in the prospectus,
                      receive all of the principal payments until all of the
                      groups are retired. Aside from market risk, the primary
                      risk involved in any mortgage security, such as a CMO
                      issuance, is its exposure to prepayment risk. To the
                      extent a particular group of bonds is exposed to this
                      risk, the bondholder is generally compensated in the form
                      of higher yield (see "Investment Risks"). In order to
                      provide security, in addition to the underlying
                      collateral, many CMO issues also include minimum
                      reinvestment rate and minimum sinking-fund guarantees.
                      Typically, the Portfolio will invest in those CMOs that
                      most appropriately reflect its average maturity and market
                      risk profiles. Consequently, the Short-Term Portfolio
                      invests only in CMOs with highly predictable, short-term
                      average maturities.
 
                      The maturity of some classes of CMOs may be very difficult
                      to predict because any such predictions are highly
                      dependent upon assumptions regarding the prepay-
 
                                       10
<PAGE>   124
 
   
                      ments which CMOs may experience. Deviations in the actual
                      prepayments experienced may significantly affect the
                      ultimate maturity of CMOs, and in such an event, the
                      maturity and risk characteristics of CMOs purchased by the
                      Portfolio may be significantly greater or less than
                      intended. The possibility that rising interest rates may
                      cause prepayments to occur at a slower than expected rate
                      is known as extension risk. This particular risk may
                      effectively change a CMO which was considered short- or
                      intermediate-term at the time of purchase into a long-term
                      security. Alternatively, there are certain classes of CMOs
                      that are by design constructed to have highly predictable
                      average maturities. Such CMOs will retain their relative
                      predictability over a broad range of prepayment
                      experience. The Portfolio expects to control extension
                      risk by purchasing these specific classes of CMOs which,
                      in the adviser's opinion, are reasonably predictable.
    
 
THE PORTFOLIO
MAY INVEST IN
ASSET-BACKED
SECURITIES
                      The Portfolio may invest in asset-backed securities. These
                      securities represent partial ownership in pools of
                      consumer or commercial loans -- such as mortgage or
                      automobile loans, credit card balances, equipment lease
                      loans, and collateralized bond obligations (bonds backed
                      by other securities).
 
                      Besides being backed by the loans or other assets in the
                      pool, many of these securities come with credit
                      enhancements as additional protection against default.
                      Such credit enhancements could include
                      over-collateralization or insurance coverage provided by a
                      highly rated (usually AAA) institution other than the
                      security's issuer.
 
                      The value of asset-backed securities ultimately depends on
                      whether the borrowers repay the underlying loans, and
                      whether the credit enhancements, if any, are adequate.
                      Despite any credit enhancements, the value of an
                      asset-backed security may fluctuate because of several
                      factors, including:
 
                      - The market's perception of the value of the assets
                        backing the security.
 
                      - The creditworthiness of the agent in charge of
                        collecting loan payments and passing them through to
                        security holders, the firm that originated the loans,
                        and the institution providing any credit insurance or
                        guarantees.
 
                      - The nature of any insurance or other credit
                        enhancements.
 
                      Another risk of asset-backed securities, especially in
                      periods of declining interest rates, is that borrowers may
                      prepay the underlying loans. These prepayments shorten the
                      weighted average life of an asset-backed security and may
                      lower its return.
 
   
PORTFOLIO TURNOVER
RATES WILL VARY       Although it generally seeks to invest for the long term,
                      the Short-Term Corporate Portfolio retains the right to
                      sell securities regardless of how long they have been
                      held. It is anticipated that the annual portfolio turnover
                      rate for the Portfolio will be relatively high, but will
                      not exceed 300%. The relatively high turnover is due to
                      the short-term maturities of the securities purchased. A
                      higher portfolio turnover rate will cause the Portfolio to
                      incur additional brokerage costs and may cause the
                      Portfolio to realize a higher level of capital gains or
                      losses.
    
- --------------------------------------------------------------------------------
 
                                       11
<PAGE>   125
 
INVESTMENT
LIMITATIONS
THE PORTFOLIO HAS
ADOPTED
CERTAIN FUNDAMENTAL
LIMITATIONS           The Portfolio has adopted limitations on some of its
                      investment policies. Some of these limitations are that
                      the Portfolio will not:
 
                      (a) with respect to 75% of its assets, invest more than 5%
                          of the value of its assets in the securities of any
                          single company or purchase more than 10% of the voting
                          securities of any issuer (except for securities issued
                          or guaranteed by the U.S. Government or any of its
                          agencies or instrumentalities);
 
                      (b) invest more than 5% of its assets in the securities of
                          companies that have a continuous operating history of
                          less than three years;
 
                      (c) invest more than 25% of its assets in any one
                          industry, provided that: (i) this limitation does not
                          apply to obligations issued or guaranteed by the U.S.
                          Government or its agencies or instrumentalities; (ii)
                          utility companies will be divided according to their
                          services (for example, gas, gas transmission,
                          electric, electric and gas, and telephone will each be
                          considered a separate industry); and (iii) financial
                          service companies will be classified according to the
                          end users of their services (for example, automobile
                          finance, bank finance, and diversified finance will be
                          considered as separate industries);
 
                      (d) borrow money, except that the Portfolio may borrow
                          from banks (or through reverse repurchase agreements),
                          for temporary or emergency (not leveraging) purposes,
                          including the meeting of redemption requests which
                          might otherwise require the untimely disposition of
                          securities, in an amount not exceeding 15% of the
                          value of the Portfolio's net assets (including the
                          amount borrowed and the value of any outstanding
                          reverse repurchase agreements) at the time the
                          borrowing is made. Whenever borrowings exceed 5% of
                          the value of the Portfolio's net assets, the Portfolio
                          will not make any additional investments; and
 
                      (e) pledge, mortgage or hypothecate its assets to an
                          extent greater than 5% of the value of its total
                          assets.
 
                      A complete list of the Portfolio's investment limitations
                      can be found in the Statement of Additional Information.
                      These limitations are fundamental and may be changed only
                      by approval of a majority of the Fund's shareholders.
- --------------------------------------------------------------------------------
 
MANAGEMENT OF
THE PORTFOLIO
VANGUARD ADMINISTERS
AND DISTRIBUTES THE
PORTFOLIO             The Portfolio is one of nine Portfolios of Vanguard Fixed
                      Income Securities Fund, a member of The Vanguard Group of
                      Investment Companies, a family of more than 30 investment
                      companies with more than 95 distinct portfolios and total
                      assets in excess of $370 billion. Through their
                      jointly-owned subsidiary, The Vanguard Group, Inc.
                      ("Vanguard"), the Fund and the other funds in the Group
                      obtain at cost virtually all of their corporate
                      management, administrative, shareholder accounting and
                      distribution services. Vanguard also provides investment
                      advisory services on an at-cost basis to certain Vanguard
                      funds. As a result of Vanguard's unique corporate
                      structure, the Vanguard funds have costs substantially
                      lower than those of most competing mutual funds. In 1997,
                      the average expense ratio (annual costs including advisory
                      fees divided by total net assets) for the Vanguard funds
                      amounted to approximately 0.28% compared to an average of
                      1.24% for the mutual fund industry (data provided by
                      Lipper Analytical Services).
                                       12
<PAGE>   126
 
                      The Officers of the Fund oversee its day-to-day operations
                      and are responsible to the Fund's Board of Directors. The
                      Directors set broad policies for the Fund and choose its
                      Officers. A list of the Directors and Officers of the Fund
                      and a statement of their present positions and principal
                      occupations during the past five years can be found in the
                      Statement of Additional Information.
 
                      Vanguard employs a supporting staff of management and
                      administrative personnel needed to provide the requisite
                      services to the funds and also furnishes the funds with
                      necessary office space, furnishings and equipment. Each
                      fund pays its share of Vanguard's net expenses, which are
                      allocated among the funds under methods approved by the
                      Board of Directors (Trustees) of each fund. In addition,
                      each fund bears its own direct expenses, such as legal,
                      auditing and custodian fees.
 
                      Vanguard also provides distribution and marketing services
                      to the Vanguard funds. The funds are available on a
                      no-load basis (i.e., there are no sales commissions or
                      12b-1 fees). However, each fund bears its share of the
                      Group's distribution costs.
- --------------------------------------------------------------------------------
 
INVESTMENT
ADVISER
VANGUARD MANAGES THE
PORTFOLIO'S INVESTMENTS
                      The Short-Term Corporate Portfolio receives all investment
                      advisory services on an at-cost basis from Vanguard's
                      Fixed Income Group. The Group provides investment advisory
                      services to more than 40 Vanguard money market and bond
                      portfolios, both taxable and tax-exempt. Total assets
                      under management by Vanguard's Fixed Income Group were
                      more than $100 billion as of January 31, 1998.
 
   
                      Ian A. MacKinnon, Managing Director of Vanguard, has been
                      in charge of the Fixed Income Group since its inception in
                      1981. Mr. MacKinnon is responsible for setting the broad
                      investment strategies employed by the Portfolio, and for
                      overseeing the portfolio manager who implements those
                      strategies on a day-to-day basis.
    
 
                      The Portfolio's portfolio manager is Robert F. Auwaerter,
                      a Principal of Vanguard. Mr. Auwaerter also serves as
                      portfolio manager of the Short-Term U.S. Treasury,
                      Long-Term U.S. Treasury, Intermediate-Term U.S. Treasury,
                      and Intermediate-Term Corporate Portfolios. Associated
                      with the Fixed Income Group since 1981, Mr. Auwaerter has
                      managed the Short-Term Corporate Portfolio since 1983.
 
                      The Fixed Income Group manages the investment and
                      reinvestment of the assets of the Portfolio and
                      continuously reviews, supervises and administers the
                      Portfolio's investment program, subject to the maturity
                      and quality standards specified in this Prospectus and
                      supplemental guidelines approved by the Fund's Board of
                      Directors. The Fixed Income Group's selection of
                      investments for the Portfolio is based on: (a) continuing
                      credit analysis of those instruments held in the Portfolio
                      and those being considered for inclusion therein; (b)
                      possible disparities in yield relationships between
                      different money market instruments; and (c) actual or
                      anticipated movements in the general level of interest
                      rates.
 
                      Vanguard's Fixed Income Group is also responsible for the
                      placement of portfolio transactions and the negotiation of
                      commissions for the Portfolio. The purchase and sale of
                      investment securities will ordinarily be principal
                      transactions. Portfolio securities will normally be
                      purchased directly from the issuer or from an underwriter
                      or market maker for the securities. There usually will be
                      no brokerage
 
                                       13
<PAGE>   127
 
                      commissions paid by a Portfolio for securities purchased
                      from an issuer. Purchases from underwriters of securities
                      will include a commission or concession paid by the issuer
                      to the underwriter, and purchases from dealers serving as
                      market makers will include a dealer's mark-up.
 
                      The adviser is authorized to choose brokers or dealers to
                      handle the purchase and sale of the Portfolio's
                      securities, and is directed to get the best available
                      price and most favorable execution from these brokers with
                      respect to all transactions. At times, the adviser may
                      choose brokers who charge higher commissions in the
                      interests of obtaining better execution of a transaction.
                      If more than one broker can obtain the best available
                      price and favorable execution of a transaction, then the
                      adviser is authorized to choose a broker who, in addition
                      to executing the transaction, will provide research
                      services to the adviser or the Portfolio. However, the
                      adviser will not pay higher commissions specifically for
                      the purpose of obtaining research services. The Portfolio
                      may direct the adviser to use a particular broker for
                      certain transactions in exchange for commission rebates or
                      research services provided to the Portfolio.
 
                      Vanguard's Fixed Income Group may occasionally make
                      recommendations to other Vanguard Funds or clients which
                      result in their purchasing or selling securities
                      simultaneously with the Portfolio. As a result, the demand
                      for securities being purchased or the supply of securities
                      being sold may increase, and this could have an adverse
                      effect on the price of those securities. It is the policy
                      of the Fixed Income Group not to favor one client over
                      another in making recommendations or placing an order. If
                      two or more clients are purchasing a given security on the
                      same day from the same broker/dealer, such transactions
                      may be averaged as to price.
- --------------------------------------------------------------------------------
 
DIVIDENDS,
CAPITAL GAINS
AND TAXES
DIVIDENDS ARE PAID ON
THE FIRST BUSINESS DAY
OF EACH MONTH         Dividends consisting of virtually all of the ordinary
                      income of the Portfolio are declared daily and are payable
                      to shareholders of record at the time of declaration. Such
                      dividends are paid on the first business day of each
                      month. Net capital gains distributions, if any, will be
                      made annually.
 
                      The Portfolio's dividend and capital gains distributions
                      may be reinvested in additional shares or received in
                      cash. See "Choosing a Distribution Option" for a
                      description of these distribution methods.
 
                      In order to satisfy certain requirements of the Tax Reform
                      Act of 1986, the Portfolio may declare year-end dividend
                      and capital gains distributions during December. Such
                      distributions, if received by shareholders by January 31,
                      are deemed to have been paid by the Portfolio and received
                      by shareholders on December 31 of the prior year.
 
                      The Portfolio intends to continue to qualify for taxation
                      as a "regulated investment company" under the Internal
                      Revenue Code so that the Portfolio will not be subject to
                      federal income tax to the extent its income is distributed
                      to shareholders. Dividends paid by the Portfolio from net
                      investment income, whether received in cash or reinvested
                      in additional shares, will be taxable to shareholders as
                      ordinary income. For corporate investors, dividends paid
                      by the Portfolio from net investment income will generally
                      not qualify for the intercorporate dividends-received
                      deduction.
 
                                       14
<PAGE>   128
 
                      Distributions paid by the Portfolio from long-term capital
                      gains, whether received in cash or reinvested in
                      additional shares, are taxable as long-term capital gains,
                      regardless of the length of time you have owned shares in
                      the Portfolio. Capital gains distributions are made when
                      the Portfolio realizes net capital gains on sales of
                      portfolio securities during the year. For the Portfolio,
                      realized capital gains are not expected to be a
                      significant or predictable part of investment return.
 
                      The Portfolio will notify you annually as to the tax
                      status of dividend and capital gains distributions paid by
                      the Portfolio. The Portfolio is managed without regard to
                      tax ramifications.
 
                      Dividends and capital gains are calculated and distributed
                      the same way for each class of shares. The amount of any
                      income dividends per share will vary, however, generally
                      due to the differences in marketing and distribution,
                      account maintenance and shareholder services expenses for
                      the Portfolio's separate share classes.
 
A CAPITAL GAIN OR LOSS
MAY BE REALIZED UPON
EXCHANGE OR
REDEMPTION            A sale of shares of the Portfolio is a taxable event and
                      may result in a capital gain or loss. A capital gain or
                      loss may be realized from an ordinary redemption of
                      shares, a checkwriting redemption, or an exchange of
                      shares between two mutual funds (or two portfolios of a
                      mutual fund).
 
                      Dividend distributions, capital gains distributions, and
                      capital gains or losses from redemptions and exchanges may
                      be subject to state and local taxes. However, depending on
                      provisions of your state's tax law, the portion of the
                      Portfolio's income derived from "full faith and credit"
                      U.S. Treasury obligations may be exempt from state and
                      local taxes. The Portfolio will indicate each year the
                      portion of the Portfolio's income, if any, that may
                      qualify for this exemption.
 
                      The Portfolio is required to withhold 31% of taxable
                      dividends, capital gains distributions, and redemptions
                      paid to shareholders who have not complied with IRS
                      taxpayer identification regulations. You may avoid this
                      withholding requirement by certifying on your Account
                      Registration Form your proper Social Security or employer
                      identification number and by certifying that you are not
                      subject to backup withholding.
 
                      The Portfolio has obtained a Certificate of Authority to
                      do business as a foreign corporation in Pennsylvania and
                      does business and maintains an office in that state. In
                      the opinion of counsel, the shares of the Portfolio are
                      exempt from Pennsylvania personal property taxes.
 
                      The tax discussion set forth above is included for general
                      information only. Prospective investors should consult
                      their own tax advisers concerning the tax consequences of
                      an investment in the Portfolio.
- --------------------------------------------------------------------------------
 
THE SHARE PRICE OF
EACH CLASS OF THE
PORTFOLIO             The Portfolio's share price, or "net asset value" per
                      share, is calculated by dividing the net assets attributed
                      to each share class, by the total number of shares
                      outstanding for that share class. The net asset value is
                      determined as of the close of the New York Stock Exchange
                      (generally 4:00 p.m. Eastern time) on each day that the
                      Exchange is open for trading.
 
                                       15
<PAGE>   129
 
                      Short-term instruments (those acquired with remaining
                      maturities of 60 days or less) may be valued at cost, plus
                      or minus any amortized discount or premium, which
                      approximates market value.
 
                      Bonds and other fixed income securities may be valued on
                      the basis of prices provided by a pricing service when
                      such prices are believed to reflect the fair market value
                      of such securities. The prices provided by a pricing
                      service may be determined without regard to bid or last
                      sale prices of each security, but take into account
                      institutional-size transactions in similar groups of
                      securities as well as any developments related to specific
                      securities.
 
                      Other assets and securities for which no quotations are
                      readily available or which are restricted as to sale (or
                      resale) are valued by such methods as the Board of
                      Directors deems in good faith to reflect fair value.
 
                      The share price for the Portfolio can be found daily in
                      the mutual fund listings of most major newspapers under
                      the heading of Vanguard Funds.
- --------------------------------------------------------------------------------
 
   
GENERAL
INFORMATION           The Fund is a Maryland corporation. The Articles of
                      Incorporation permit the Directors to issue 4,550,000,000
                      shares of common stock, with a $.001 par value. The Board
                      of Directors has the power to designate one or more series
                      ("Portfolios") of shares of common stock and to classify
                      or reclassify any unissued shares with respect to such
                      series. Currently the Fund is offering shares of nine
                      Portfolios. The Short-Term Corporate Portfolio offers two
                      separate classes of shares, Investor Shares and
                      Institutional Shares. The Investor Shares are available to
                      investors who meet the minimum initial investment of
                      $3,000 ($1,000 for retirement plan accounts) and may
                      require special employee benefit plan services. The
                      Institutional Shares are designed for investors who
                      generally do not require special employee benefit plan
                      services and meet the minimum initial investment of $50
                      million.
    
 
                      The shares of each Portfolio are fully paid and
                      non-assessable; have no preference as to conversion,
                      exchange, dividends, retirement or other features; and
                      have no pre-emptive rights. Such shares have
                      non-cumulative voting rights, meaning that the holders of
                      more than 50% of the shares voting for the election of
                      Directors can elect 100% of the Directors if they so
                      choose.
 
                      Annual meetings of shareholders will not be held except as
                      required by the Investment Company Act of 1940 and other
                      applicable law. An annual meeting will be held to vote on
                      the removal of a Director or Directors of the Fund if
                      requested in writing by the holders of not less than 10%
                      of the outstanding shares of the Fund.
 
                      All securities and cash for the Short-Term Corporate
                      Portfolio are held by CoreStates Bank, N.A., Philadelphia,
                      PA, which also holds daily cash balances that are used by
                      the Portfolio to invest in repurchase agreements or
                      securities acquired in these transactions. The Vanguard
                      Group, Inc., Valley Forge, PA, serves as the Portfolio's
                      Transfer and Dividend Disbursing Agent. Price Waterhouse
                      LLP serves as independent accountants for the Portfolio
                      and will audit its financial statements annually. The
                      Portfolio is not involved in any litigation.
- --------------------------------------------------------------------------------
 
                                       16
<PAGE>   130
 
                               SHAREHOLDER GUIDE
 
OPENING AN
ACCOUNT AND
PURCHASING
SHARES                To open an account, complete an Account Registration Form
                      and mail it to:
 
                           THE VANGUARD GROUP
                           VANGUARD FIXED INCOME SECURITIES FUND
                           SHORT-TERM CORPORATE PORTFOLIO --
                                INSTITUTIONAL SHARES
                           ATTN: INSTITUTIONAL INVESTOR SERVICES
                           P.O. BOX 1472
                           VALLEY FORGE, PA 19482
 
                      For express or registered mail, send your registration
                      form to: The Vanguard Group, Vanguard Fixed Income
                      Securities Fund, SHORT-TERM CORPORATE PORTFOLIO --
                      INSTITUTIONAL SHARES, Attn: Institutional Investor
                      Services, 100 Vanguard Boulevard, Malvern, PA 19355.
 
                      Once the account has been opened, Vanguard will assign an
                      Institutional Investor Services Representative for future
                      account transactions.
 
   
                      Shares of the Portfolio may be purchased by Federal Funds
                      wire. The minimum initial investment for the Portfolio is
                      $50 million. Please contact your Institutional Investor
                      Service Representative or call The Vanguard Group at
                      1-800-523-1036 to notify the Portfolio of the intended
                      investment and to receive an account number. Wiring
                      instructions are provided below.
    
 
                      Subsequent investments of $5 million or more will be
                      credited to an account on the date of purchase if Vanguard
                      is notified one business day in advance of the intended
                      purchase and a Federal Funds wire is received by 4:00 p.m.
                      (Eastern time) on the date of purchase. See "Trade Date
                      Policy."
 
                      The Fund's shares are purchased at the next-determined net
                      asset value after your investment has been received in the
                      form of Federal Funds. See "When Your Account Will Be
                      Credited." The Fund is offered on a no-load basis (i.e.,
                      there are no sales commissions or 12b-1 fees).
 
PURCHASE
RESTRICTIONS          1) Because of the risks associated with bond investments,
                         the Portfolio is intended to be a long-term investment
                         vehicle and is not designed to provide investors with a
                         means of speculating on short-term market movements.
                         Consequently, the Portfolio reserves the right to
                         reject any specific purchase (and exchange purchase)
                         request. The Fund also reserves the right to suspend
                         the offering of shares for a period of time.
 
                      2) Vanguard will not accept third-party checks to purchase
                         shares of the Fund. Please be sure your purchase check
                         is made payable to The Vanguard Group.
 
ADDITIONAL
INVESTMENTS
Please contact your
Service Representative Additional investments may be made at any time by wiring
                       monies to Vanguard. As noted above, investments of $5
                       million or more require prior-day notification to qualify
                       for credit on the date of purchase. To ensure prompt
                       investment, please notify your Institutional Investor
                       Services Representative in advance of the wire.
- --------------------------------------------------------------------------------
 
                                       17
<PAGE>   131
 
<TABLE>
<S>                                               <C>
PURCHASING BY WIRE                                CORESTATES BANK, N.A.
Money should be                                   ABA 031000011
wired to:                                         CORESTATES NO. 0101 9897
                                                  ATTN: VANGUARD
BEFORE WIRING                                     VANGUARD FIXED INCOME SECURITIES FUND --
Please contact your                               VANGUARD SHORT-TERM CORPORATE PORTFOLIO INSTITUTIONAL
Service Representative                            SHARES
                                                  ACCOUNT NUMBER
                                                  ACCOUNT REGISTRATION
</TABLE>
 
   
                      To assure proper receipt, please be sure your bank
                      includes the Portfolio name, the account number Vanguard
                      has assigned to you and the eight-digit CoreStates number.
                      If you are opening a new account, complete the Account
                      Registration Form and mail it to the address at the top of
                      Page 17 after completing your wire arrangement. NOTE:
                      Federal Funds wire purchase orders will be accepted only
                      when the Portfolio and Custodian Bank are open for
                      business.
    
- --------------------------------------------------------------------------------
PURCHASING BY
EXCHANGE (from a
Vanguard account)     You may open an account or purchase additional shares by
                      making an exchange from an existing Vanguard Fund account.
                      However, the Portfolio reserves the right to refuse any
                      exchange purchase request. Call your Service
                      Representative (1-800-523-1036.)
 
DISTRIBUTION
OPTIONS               Dividend and capital gains distributions paid by the
                      Portfolio will be automatically reinvested in additional
                      shares of the same class of shares of the Fund that you
                      own. A cash dividend option is also available. Please
                      contact your Service Representative for further
                      information.
 
CERTIFICATES
                      Share certificates will not be issued for the Portfolio.
 
ELECTRONIC
PROSPECTUS
DELIVERY
                      You may receive a prospectus for the Portfolio or any of
                      the Vanguard Funds in an electronic format through
                      Vanguard's website at www.vanguard.com. For additional
                      information please see "Other Vanguard
                      Services -- Computer Access."
- --------------------------------------------------------------------------------
 
TRADE DATE
POLICY
                      Investments will be credited on the date of purchase under
                      the following conditions:
 
   
                      -  FOR INVESTMENTS OF $5 MILLION OR MORE:  The Portfolio
                         must be notified of the intended purchase by the close
                         of trading on the New York Stock Exchange (the
                         "Exchange"), generally 4:00 p.m. Eastern time, on the
                         prior business day and the Federal Funds wire must be
                         received by Vanguard by the close of trading on the
                         Exchange on the date of purchase.
    
 
                      -  FOR INVESTMENTS OF LESS THAN $5 MILLION:  The Fund must
                         be notified of the intended purchase by 10:45 a.m.
                         Eastern time on the day of purchase and the Federal
                         Funds wire must be received by the close of the
                         Exchange.
 
                      Generally, if these requirements are not met, an
                      investment will be credited to the account on the business
                      day following receipt of a Federal Funds wire.
 
                                       18
<PAGE>   132
 
   
WHEN YOUR ACCOUNT
WILL BE CREDITED      The trade date, the day on which an account is credited,
                      is generally the day on which the Portfolio receives an
                      investment in the form of Federal Funds. For purchases by
                      Federal Funds wire or by exchange, the Portfolio is
                      credited immediately with Federal Funds. If a purchase by
                      Federal Funds wire or exchange is received by the close of
                      the Exchange, the trade date is the day of receipt
                      assuming proper notification has been given, as described
                      above. If a purchase is received after the close of
                      trading on the Exchange, the trade date is the business
                      day following the receipt of the wire or exchange.
    
- --------------------------------------------------------------------------------
SELLING
SHARES
WIRE PROCEEDS         Any portion of an account may be withdrawn by contacting
                      your Institutional Investor Services Representative. The
                      redemption proceeds will be wired to the bank account
                      indicated on the Account Registration Form on the business
                      day following receipt of a request.
 
                      For a redemption of an entire account balance, accrued
                      dividends will not be included in the initial redemption
                      wire, but will be sent separately by check or wire.
 
                      Wire redemptions of less than $5,000 are subject to a $5
                      charge deducted from the principal in your account. There
                      is no charge for wire redemptions of $5,000 or more, or
                      for subsequent dividend wires.
 
                      For our mutual protection, wiring instructions must be on
                      file at Vanguard prior to executing any redemption
                      request. A request to change the bank account associated
                      with the wire redemption feature or a request to wire
                      funds to a bank other than that on file must be received
                      in writing. A signature guarantee of an authorized officer
                      is required if the bank registration is not identical to
                      the Vanguard Fund account registration.
 
OTHER REDEMPTION
INFORMATION
                      The Portfolio may suspend the redemption rights or
                      postpone payment at times when the New York Stock Exchange
                      is closed or under any emergency circumstances as
                      determined by the United States Securities and Exchange
                      Commission.
- --------------------------------------------------------------------------------
MANDATORY
CONVERSION
TO INDIVIDUAL
SHARE CLASS           The Portfolio reserves the right to convert an investor's
                      Institutional Shares into Investor Shares if the
                      investor's account balance falls below $50 million. Any
                      such conversion will be preceded by written notice to the
                      investor and will be effected on the basis of the relative
                      net asset values of the Portfolio's Investor Shares and
                      Institutional Shares. There will be no loads, fees or
                      other charges imposed on mandatory conversions.
- --------------------------------------------------------------------------------
 
EXCHANGING
SHARES                Institutional shares of the Portfolio may be exchanged for
                      those of other available Vanguard funds, but only upon
                      prior approval by Vanguard. Contact your Institutional
                      Investor Services Representative for further information.
                      Telephone exchange requests must ordinarily be received in
                      writing or by telephone by the close of trading on the
                      Exchange in order to be processed on the date of receipt.
                      The new Fund account will bear the identical registration
                      of the Vanguard Short-Term Corporate
                      Portfolio-Institutional Shares account.
 
                                       19
<PAGE>   133
 
                      Telephone exchanges are not permitted for several Vanguard
                      Funds, and there also may be restrictions on new
                      investments in certain Funds. Large exchange requests
                      (i.e., those over $250,000) require prior approval by
                      Vanguard on behalf of the Fund. Contact your Institutional
                      Investor Services Representative for full information,
                      including a prospectus.
 
                      Neither the Portfolio nor Vanguard is responsible for the
                      authenticity of exchange instructions received by
                      telephone. Every effort will be made to maintain the
                      exchange privilege. However, the Portfolio reserves the
                      right to revise or terminate its provisions, limit the
                      amount of, or reject any exchange, as deemed necessary, at
                      any time.
- --------------------------------------------------------------------------------
 
EXCHANGE
PRIVILEGE
LIMITATIONS           The Portfolio's exchange privilege is not intended to
                      afford shareholders a way to speculate on short-term
                      movements in the market. Accordingly, in order to prevent
                      excessive use of the exchange privilege that may
                      potentially disrupt the management of the Portfolio and
                      increase transaction costs, the Portfolio has established
                      a policy of limiting excessive exchange activity.
 
                      Exchange activity will not be deemed excessive if limited
                      to TWO SUBSTANTIVE EXCHANGE REDEMPTIONS (at least 30 days
                      apart) from a Portfolio during any twelve-month period.
                      "Substantive" means either a dollar amount or a series of
                      movements between Vanguard Funds that Vanguard determines,
                      in its sole discretion, could have an adverse impact on
                      the management of the Fund. Notwithstanding these
                      limitations, the Portfolio reserves the right to reject
                      any purchase request (including exchange purchases from
                      other Vanguard portfolios) that is reasonably deemed to be
                      disruptive to efficient portfolio management.
- --------------------------------------------------------------------------------
 
IMPORTANT
INFORMATION
ABOUT TELEPHONE
TRANSACTIONS          The ability to initiate redemptions (except wire or Fund
                      Express redemptions) and exchanges by telephone is
                      automatically established on your account unless you
                      request in writing that telephone transactions on your
                      account not be permitted. The ability to initiate wire
                      redemptions by telephone will be established on your
                      account only if you specifically elect this option in
                      writing.
 
                      To protect your account from losses resulting from
                      unauthorized or fraudulent telephone instructions,
                      Vanguard adheres to the following security procedures:
 
                      1.  SECURITY CHECK.  To request a transaction by
                          telephone, the caller must know (i) the name of the
                          Portfolio; (ii) the 10-digit account number; (iii) the
                          exact name and address used in the registration; and
                          (iv) the Social Security or employer identification
                          number listed on the account.
 
                      2.  PAYMENT POLICY.  The proceeds of any telephone
                          redemption by mail will be made payable to the
                          registered shareowner and mailed to the address of
                          record only. In the case of a telephone redemption by
                          wire, the wire transfer will be made only in
                          accordance with the shareowner's prior written
                          instructions.
 
                      Neither the Portfolio nor Vanguard will be responsible for
                      the authenticity of transaction instructions received by
                      telephone, provided that reasonable security
 
                                       20
<PAGE>   134
 
                      procedures have been followed. Vanguard believes that the
                      security procedures described above are reasonable, and
                      that if such procedures are followed, you will bear the
                      risk of any losses resulting from unauthorized or
                      fraudulent telephone transactions on your account.
- --------------------------------------------------------------------------------
 
OTHER
ACCOUNT
INFORMATION           For corporate investors, a current corporate resolution
                      must be maintained on file at Vanguard at all times. The
                      initial application serves as a corporate resolution. Any
                      revisions to a corporate resolution must be submitted to
                      your Institutional Investor Services Representative at
                      Vanguard.
 
                      To change the registration of an account, a request must
                      be submitted in writing to Vanguard and include the
                      following information: the account number and portfolio
                      name; authorized signatures; any applicable signature
                      guarantees; and other supporting legal documents as
                      necessary.
 
                      All requests should be mailed to the following address:
 
                                       THE VANGUARD GROUP
                                 ATTN: INSTITUTIONAL INVESTOR SERVICES
                                 P.O. BOX 1472
                                 VALLEY FORGE, PA 19482
- --------------------------------------------------------------------------------
OTHER VANGUARD
SERVICES
COMPUTER ACCESS       Use your personal computer to learn more about Vanguard's
                      funds and services; keep in touch with your Vanguard
                      accounts; map out a long-term investment strategy;
                      initiate certain transactions; and ask questions, make
                      suggestions, and send messages to Vanguard.
 
VANGUARD ONLINE
www.vanguard.com      Our education-oriented website provides timely news and
                      information about Vanguard's funds and services; an online
                      "university" that offers a variety of mutual fund classes;
                      and easy-to-use, interactive tools to help you create your
                      own investment and retirement strategies.
- --------------------------------------------------------------------------------
 
                                       21
<PAGE>   135
 
                     [THIS PAGE INTENTIONALLY LEFT BLANK.]
<PAGE>   136
 
- --------------------------------------------------------------------------------
 
      [VANGUARD LOGO]
 
      ---------------------------------
 
      THE VANGUARD GROUP
      P.O. Box 2900
      Valley Forge, PA 19482
 
      FOR PARTICIPANTS IN
       EMPLOYER-SPONSORED PLANS
      1-800-523-1188
 
      FOR OTHER INSTITUTIONAL
       INVESTORS
      1-800-523-1036
 
      TRANSFER AGENT
      The Vanguard Group, Inc.
      P.O. Box 2900
      Valley Forge, PA 19482
 
      ELECTRONIC ACCESS TO THE
       VANGUARD MUTUAL FUND
       EDUCATION AND INFORMATION
       CENTER
      WORLD WIDE WEB
      www.vanguard.com
 
      E-MAIL
      [email protected]
 
   
      I858
    
 
- --------------------------------------------------------------------------------
<PAGE>   137
 
                                     PART B
 
                  VANGUARD FIXED INCOME SECURITIES FUND, INC.
 
                      STATEMENT OF ADDITIONAL INFORMATION
 
                                  MAY 29, 1998
 
     This Statement is not a prospectus but should be read in conjunction with
the Fund's current Prospectuses, as they may be amended from time to time. The
Fund's current Prospectuses are dated May 29, 1998. To obtain a Prospectus
please call:
 
                      VANGUARD INVESTOR INFORMATION CENTER
                                 1-800-662-7447
                                       or
                        VANGUARD INSTITUTIONAL SERVICES
                                 1-800-523-1036
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
The Fund....................................................   B-1
Investment Objective and Policies...........................   B-1
Purchase of Shares..........................................   B-6
Redemption of Shares........................................   B-6
Signature Guarantees........................................   B-6
Investment Limitations......................................   B-7
Management of the Fund......................................   B-9
Investment Advisory Services................................  B-12
Portfolio Transactions......................................  B-14
Yield and Total Return......................................  B-15
Financial Statements........................................  B-16
Performance Measures........................................  B-16
Other Definitions...........................................  B-17
Appendix -- Description of Securities and Ratings...........  B-18
</TABLE>
 
                                    THE FUND
 
   
     Vanguard Fixed Income Securities Fund, Inc. (the "Fund") is an open-end,
diversified, management investment company whose shares are currently offered in
nine distinct portfolios (the "Portfolios"). Each Portfolio of the Fund has its
own investment objective and policies.
    
 
                       INVESTMENT OBJECTIVE AND POLICIES
 
     The following policies supplement the investment objective and policies set
forth in the Fund's Prospectuses:
 
     REPURCHASE AGREEMENTS.  Each Portfolio may invest in repurchase agreements
with commercial banks, brokers or dealers either for defensive purposes due to
market conditions or to generate income from its excess cash balances. A
repurchase agreement is an agreement under which a Portfolio acquires a money
market instrument (generally a security issued by the U.S. Government or an
agency thereof, a banker's acceptance or a certificate of deposit) from a
commercial bank, broker or dealer, subject to resale to the seller at an agreed
upon price and date (normally, the next business day). A repurchase agreement
may be considered a loan collateralized by securities. The resale price reflects
an agreed upon interest rate effective for the period the instrument is held by
the Portfolio and is unrelated to the interest rate on the underlying
instrument. In these transactions, the securities acquired by the Portfolio
(including accrued interest earned thereon) must have a total value in excess of
the value of the repurchase agreement and are held by a custodian bank until
 
                                       B-1
<PAGE>   138
 
repurchased. In addition, the Fund's Board of Directors will monitor a
Portfolio's repurchase agreement transactions generally and will establish
guidelines and standards for review by the investment adviser of the
creditworthiness of any bank, broker or dealer party to a repurchase agreement
with the Portfolio. No more than an aggregate of 15% of a Portfolio's assets, at
the time of investment, will be invested in repurchase agreements having
maturities longer than seven days and securities subject to legal or contractual
restrictions on resale for which there are no readily available market
quotations. See "Illiquid Securities" below.
 
     The use of repurchase agreements involves certain risks. For example, if
the other party to the agreement defaults on its obligation to repurchase the
underlying security at a time when the value of the security has declined, a
Portfolio may incur a loss upon disposition of the security. If the other party
to the agreement becomes insolvent and subject to liquidation or reorganization
under the Bankruptcy Code or other laws, a court may determine that the
underlying security is collateral for a loan by a Portfolio not within the
control of the Portfolio and therefore the realization by the Portfolio on such
collateral may be automatically stayed. Finally, it is possible that a Portfolio
may not be able to substantiate its interest in the underlying security and may
be deemed an unsecured creditor of the other party to the agreement. While each
Portfolio's management acknowledges these risks, it is expected that they can be
controlled through careful monitoring procedures.
 
     LENDING OF SECURITIES.  Each Portfolio of the Fund may lend its investment
securities to qualified brokers, dealers, banks or other financial institutions,
for short or long-term purposes, so long as the terms and the structure of such
loans are not inconsistent with the Investment Company Act of 1940, as amended,
or the Rules and Regulations or interpretations of the Securities and Exchange
Commission thereunder, which currently require that: (a) the borrower pledge and
maintain with the Portfolio collateral consisting of cash, an irrevocable letter
of credit or securities issued or guaranteed by the United States Government
having a value at all times not less than 100 percent of the value of the
securities loaned, (b) the borrower add to such collateral whenever the price of
the securities loaned rises (i.e., the borrower "marks to the market" on a daily
basis), (c) the loan be made subject to termination by the Portfolio at any
time, and (d) the Portfolio receive reasonable interest on the loan (which may
include the Portfolio's investing any cash collateral in interest bearing
short-term investments), and distributions on the loaned securities and any
increase in their market value. Each Portfolio of the Fund will not lend
securities if, as a result, the aggregate of such loans exceeds 33 1/3% of the
value of the Portfolio's total assets (including any collateral obtained in
connection with such loans). Loan arrangements made by the Fund will comply with
all other applicable regulatory requirements, including the rules of the New
York Stock Exchange, which rules presently require the borrower, after notice,
to redeliver the securities within the normal settlement time of three business
days.
 
     RESTRICTED SECURITIES.  Each Portfolio may invest in restricted securities
(privately placed debt securities) and other securities which are not readily
marketable, but will not acquire such securities if as a result they, together
with the aggregate of other securities for which no quotations are readily
available, would comprise more than 15% of the value of the Portfolio's net
assets. Pursuant to Section 4(2) of the Securities Act of 1933 and Rule 144A
under the Securities Act of 1933, as amended, if a substantial market among
qualified institutional buyers develops for restricted securities held by any
Portfolio, the Fund intends to treat such securities as liquid securities, in
accordance with procedures approved by the Fund's Board of Directors.
 
     Restricted securities may be sold only in privately negotiated transactions
or in a public offering with respect to which a registration statement is in
effect under the Securities Act of 1933. Where registration is required, a
Portfolio may be obligated to pay all or part of the registration expenses and a
considerable period may elapse between the time of the decision to sell and the
time the Portfolio may be permitted to sell a security under an effective
registration statement. If, during such a period, adverse market conditions were
to develop, the Portfolio might obtain a less favorable price than prevailed
when it decided to sell. Restricted securities will be priced at fair value as
determined in good faith by the Board of Directors. If through the appreciation
of restricted securities or the depreciation of unrestricted securities, a
Portfolio should be in a position where more than 15% of the value of its net
assets are invested in illiquid assets, including restricted securities, the
Portfolio will take appropriate steps to protect liquidity.
 
     ILLIQUID SECURITIES.  Illiquid securities are securities that may not be
sold or disposed of in the ordinary course of business within seven business
days at approximately the value at which they are being carried on a
 
                                       B-2
<PAGE>   139
 
Fund's books. An illiquid security includes repurchase agreements which have a
maturity of longer than seven days, securities which are illiquid by virtue of
the absence of a readily available market, and demand instruments with a demand
notice exceeding seven days. Illiquid securities may include securities that are
not registered under the Securities Act of 1933 (the "1933 Act"); however,
unregistered securities that can be sold to "qualified institutional buyers" in
accordance with Rule 144A under the 1933 Act will not be considered illiquid so
long as it is determined by the Fund's advisers that an adequate trading market
exists for the security. From time to time, the Fund's Board of Directors may
determine that certain restricted securities known as Rule 144A securities are
liquid and not subject to the 15% limitation described above.
 
     FOREIGN INVESTMENTS.  As indicated in the prospectuses, the Fund may
include foreign securities to a certain extent. Investors should recognize that
investing in foreign companies involves certain special considerations which are
not typically associated with investing in U.S. companies.
 
     Country Risk  As foreign companies are not generally subject to uniform
accounting, auditing and financial reporting standards and practices comparable
to those applicable to domestic companies, there may be less publicly available
information about certain foreign companies than about domestic companies.
Securities of some foreign companies are generally less liquid and more volatile
than securities of comparable domestic companies. There is generally less
government supervision and regulation of stock exchanges, brokers and listed
companies than in the U.S. In addition, with respect to certain foreign
countries, there is the possibility of expropriation or confiscatory taxation,
political or social instability, or diplomatic developments which could affect
U.S. investments in those countries.
 
     Although the Fund will endeavor to achieve most favorable execution costs
in its portfolio transactions in foreign securities, fixed commissions on many
foreign stock exchanges are generally higher than negotiated commissions on U.S.
exchanges. In addition, it is expected that the expenses for custodial
arrangements of the Fund's foreign securities will be somewhat greater than the
expenses for the custodial arrangement for handling U.S. securities of equal
value.
 
     Certain foreign governments levy withholding taxes against dividend and
interest income. Although in some countries a portion of these taxes is
recoverable, the non-recovered portion of foreign withholding taxes will reduce
the income the Fund receives from its foreign investments.
 
     Currency Risk  Since the stocks of foreign companies are frequently
denominated in foreign currencies, and since the Fund may temporarily hold
uninvested reserves in bank deposits in foreign currencies, the Fund will be
affected favorably or unfavorably by changes in currency rates and in exchange
control regulations, and may incur costs in connection with conversions between
various currencies. The investment policies of the Fund permit it to enter into
forward foreign currency exchange contracts in order to hedge holdings and
commitments against changes in the level of future currency rates. Such
contracts involve an obligation to purchase or sell a specific currency at a
future date at a price set at the time of the contract.
 
     FUTURES CONTRACTS AND OPTIONS.  Each Portfolio of the Fund except the
Short-Term Federal Portfolio may enter into futures contracts, options, and
options on futures contracts for several reasons: to simulate full investment in
the underlying securities while retaining a cash balance for Fund management
purposes, to facilitate trading, to reduce transaction costs, or to seek higher
investment returns when a futures contract is priced more attractively than the
underlying equity security or index. Futures contracts provide for the future
sale by one party and purchase by another party of a specified amount of a
specific security at a specified future time and at a specified price. Futures
contracts which are standardized as to maturity date and underlying financial
instrument are traded on national futures exchanges. Futures exchanges and
trading are regulated under the Commodity Exchange Act by the Commodity Futures
Trading Commission ("CFTC"), a U.S. Government agency. Assets committed to
futures contracts will be segregated at the Fund's custodian banks to the extent
required by law.
 
     Although futures contracts by their terms call for actual delivery or
acceptance of the underlying securities, in most cases the contracts are closed
out before the settlement date without the making or taking of delivery. Closing
out an open futures position is done by taking an opposite position ("buying" a
contract
 
                                       B-3
<PAGE>   140
 
which has previously been "sold," or "selling" a contract previously purchased)
in an identical contract to terminate the position. Brokerage commissions are
incurred when a futures contract is bought or sold.
 
     Futures traders are required to make a good faith margin deposit in cash or
government securities with a broker or custodian to initiate and maintain open
positions in futures contracts. A margin deposit is intended to assure
completion of the contract (delivery or acceptance of the underlying security)
if it is not terminated prior to the specified delivery date. Minimal initial
margin requirements are established by the futures exchange and may be changed.
Brokers may establish deposit requirements which are higher than the exchange
minimums. Futures contracts are customarily purchased and sold on margin
deposits which may range upward from less than 5% of the value of the contract
being traded.
 
     After a futures contract position is opened, the value of the contract is
marked to market daily. If the futures contract price changes to the extent that
the margin on deposit does not satisfy margin requirements, payment of
additional "variation" margin will be required. Conversely, change in the
contract value may reduce the required margin, resulting in a repayment of
excess margin to the contract holder. Variation margin payments are made to and
from the futures broker for as long as the contract remains open. The Portfolios
expect to earn interest income on their margin deposits.
 
     Traders in futures contracts may be broadly classified as either "hedgers"
or "speculators." Hedgers use the futures markets primarily to offset
unfavorable changes in the value of securities otherwise held for investment
purposes or expected to be acquired by them. Speculators are less inclined to
own the securities underlying the futures contracts which they trade, and use
futures contracts with the expectation of realizing profits from fluctuations in
the prices of underlying securities. The Portfolios intend to use futures
contracts only for bona fide hedging purposes.
 
     Regulations of the CFTC applicable to the Fund require that all of its
futures transactions constitute bona fide hedging transactions except to the
extent that the aggregate initial margins and premiums required to establish any
non-hedging positions do not exceed five percent of the value of the Fund's
portfolio. A Portfolio will only sell futures contracts to protect securities it
owns against price declines or purchase contracts to protect against an increase
in the price of securities it intends to purchase.
 
     Although techniques other than the sale and purchase of futures contracts
could be used to control each Portfolio's exposure to market fluctuations, the
use of futures contracts may be a more effective means of hedging this exposure.
While a Portfolio will incur commission expenses in both opening and closing out
futures positions, these costs are lower than transaction costs incurred in the
purchase and sale of the underlying securities.
 
     RESTRICTIONS ON THE USE OF FUTURES CONTRACTS.  A Portfolio of the Fund will
not enter into futures contract transactions to the extent that, immediately
thereafter, the sum of its initial margin deposits on open contracts exceeds 5%
of the market value of the Portfolio's total assets. In addition, a Portfolio of
the Fund will not enter into futures contracts to the extent that its
outstanding obligations to purchase securities under these contracts would
exceed 20% of the Portfolio's total assets.
 
   
     RISK FACTORS IN FUTURES TRANSACTIONS.  Positions in futures contracts may
be closed out only on an exchange which provides a secondary market for such
futures. However, there can be no assurance that a liquid secondary market will
exist for any particular futures contract at any specific time. Thus, it may not
be possible to close a futures position. In the event of adverse price
movements, a Portfolio would continue to be required to make daily cash payments
to maintain its required margin. In such situations, if the Portfolio has
insufficient cash, it may have to sell portfolio securities to meet daily margin
requirements at a time when it may be disadvantageous to do so. In addition, the
Portfolio may be required to make delivery of the instruments underlying futures
contracts it holds. The inability to close options and futures positions also
could have an adverse impact on the ability to hedge it effectively.
    
 
     Each Portfolio will minimize the risk that it will be unable to close out a
futures contract by only entering into futures which are traded on national
futures exchanges and for which there appears to be a liquid secondary market.
 
                                       B-4
<PAGE>   141
 
     The risk of loss in trading futures contracts in some strategies can be
substantial, due both to the low margin deposits required, and the extremely
high degree of leverage involved in futures pricing. As a result, a relatively
small price movement in a futures contract may result in immediate and
substantial loss (as well as gain) to the investor. For example, if at the time
of purchase, 10% of the value of the futures contract is deposited as margin, a
subsequent 10% decrease in the value of the futures contract would result in a
total loss of the margin deposit, before any deduction for the transaction
costs, if the account were then closed out. A 15% decrease would result in a
loss equal to 150% of the original margin deposit if the contract were closed
out. Thus, a purchase or sale of a futures contract may result in losses in
excess of the amount invested in the contract. Additionally, a Portfolio incurs
the risk that its adviser will incorrectly predict future interest rate trends.
However, because the futures strategies of the Portfolios are engaged in only
for hedging purposes, the Advisers do not believe that the Portfolios are
subject to the risks of loss frequently associated with futures transactions.
The Portfolios would presumably have sustained comparable losses if, instead of
the futures contract, they had invested in the underlying financial instrument
and sold it after the decline.
 
     Utilization of futures transactions by a Portfolio does involve the risk of
imperfect or no correlation where the securities underlying futures contracts
have different maturities than the portfolio securities being hedged. It is also
possible that a Portfolio could both lose money on futures contracts and also
experience a decline in value of its portfolio securities. There is also the
risk of loss by a Portfolio of margin deposits in the event of bankruptcy of a
broker with whom a Portfolio has an open position in a futures contract or
related option.
 
     Most futures exchanges limit the amount of fluctuation permitted in futures
contract prices during a single trading day. The daily limit establishes the
maximum amount that the price of a futures contract may vary either up or down
from the previous day's settlement price at the end of a trading session. Once
the daily limit has been reached in a particular type of contract, no trades may
be made on that day at a price beyond that limit. The daily limit governs only
price movement during a particular trading day and therefore does not limit
potential losses, because the limit may prevent the liquidation of unfavorable
positions. Futures contract prices have occasionally moved to the daily limit
for several consecutive trading days with little or no trading, thereby
preventing prompt liquidation of future positions and subjecting some futures
traders to substantial losses.
 
     FEDERAL TAX TREATMENT OF FUTURES CONTRACTS.  Each Portfolio is required for
Federal income tax purposes to recognize as income for each taxable year its net
unrealized gains and losses on certain futures contracts held as of the end of
the year as well as those actually realized during the year. In most cases, any
gain or loss recognized with respect to a futures contract is considered to be
60% long-term capital gain or loss and 40% short-term capital gain or loss,
without regard to the holding period of the contract. Furthermore, sales of
futures contracts which are intended to hedge against a change in the value of
securities held by a Portfolio may affect the holding period of such securities
and, consequently, the nature of the gain or loss on such securities upon
disposition. A Portfolio may be required to defer the recognition of losses on
futures contracts to the extent of any unrecognized gains on related positions
held by the Portfolio.
 
     In order for each Portfolio to continue to qualify for Federal income tax
treatment as a regulated invest-
ment company, at least 90% of its gross income for a taxable year must be
derived from qualifying income; i.e., dividends, interest, income derived from
loans of securities, gains from the sale of securities or of foreign currencies
or other income derived with respect to the Portfolio's business of investing in
securities or currencies. It is anticipated that any net gain realized from the
closing out of futures contracts will be considered gain from the sale of
securities and therefore be qualifying income for purposes of the 90%
requirement.
 
     A Portfolio will distribute to shareholders annually any net capital gains
which have been recognized for Federal income tax purposes (including unrealized
gains at the end of the Portfolio's fiscal year) on futures transactions. Such
distributions will be combined with distributions of capital gains realized on
the Portfolio's other investments and shareholders will be advised on the nature
of the transactions.
 
                                       B-5
<PAGE>   142
 
                               PURCHASE OF SHARES
 
   
     Each Portfolio reserves the right in its sole discretion: (i) to suspend
the offering of its shares, (ii) to reject purchase orders when in the judgment
of management such rejection is in the best interest of the Portfolio, and (iii)
to reduce or waive the minimum investment for or any other restrictions on
initial and subsequent investments for certain fiduciary accounts such as
employee benefit plans or under circumstances where certain economies can be
achieved in sales of the Portfolio's shares.
    
 
                              REDEMPTION OF SHARES
 
   
     Each Portfolio may suspend redemption privileges or postpone the date of
payment: (i) during any period that the New York Stock Exchange (the "Exchange")
is closed, or trading on the Exchange is restricted as determined by the
Securities and Exchange Commission (the "Commission"), (ii) during any period
when an emergency exists as defined by the rules of the Commission as a result
of which it is not reasonably practicable for a Portfolio to dispose of
securities owned by it, or fairly to determine the value of its assets, and
(iii) for such other periods as the Commission may permit.
    
 
     The Fund has made an election with the Commission to pay in cash all
redemptions requested by any shareholder of record limited in amount during any
90-day period to the lesser of $250,000 or 1% of the net assets of the Fund at
the beginning of such period. Such commitment is irrevocable without the prior
approval of the Commission. Redemptions in excess of the above limits may be
paid in whole or in part, in readily marketable investment securities or in
cash, as the Directors may deem advisable; however, payment will be made wholly
in cash unless the Directors believe that economic or market conditions exist
which would make such a practice detrimental to the best interests of the Fund.
If redemptions are paid in investment securities, such securities will be valued
as set forth in the Prospectuses under "The Share Price of Each Portfolio" and a
redeeming shareholder would normally incur brokerage expenses if he converted
these securities to cash.
 
     No charge is made by a Portfolio for redemptions. Any redemption may be
more or less than the shareholder's cost depending on the market value of the
securities held by the Portfolio.
 
                              SIGNATURE GUARANTEES
 
     To protect your account, the Fund and Vanguard from fraud, signature
guarantees are required for certain redemptions. Signature guarantees enable the
Fund to verify the identity of the person who has authorized a redemption from
your account. Signature guarantees are required in connection with: (1) all
redemptions, regardless of the amount involved, when the proceeds are to be paid
to someone other than the registered owner(s), and/or to an address other than
the address of record; and (2) share transfer requests. These requirements are
not applicable to redemptions in Vanguard's prototype retirement plans, except
in connection with: (1) distributions made when the proceeds are to be paid to
someone other than the plan participant; (2) certain authorizations to effect
exchanges by telephone; and (3) when proceeds are to be wired. These
requirements may be waived by the Fund in certain instances.
 
     A signature guarantor must be a bank, broker or any other signature
guarantor that Vanguard deems acceptable. Notaries public are not acceptable
signature guarantors.
 
     The signature guarantees must appear either: (1) on the written request for
redemption; (2) on a separate instrument for assignment ("stock power") which
should specify the total number of shares to be redeemed; or (3) on all stock
certificates tendered for redemption and, if shares held by the Fund are also
being redeemed, on the letter or stock power.
 
                                       B-6
<PAGE>   143
 
                             INVESTMENT LIMITATIONS
 
     The Fund is subject to the following limitations which may not be changed
with respect to a particular Portfolio without the approval of at least a
majority of the outstanding voting securities (as defined in the Investment
Company Act of 1940) of that Portfolio. Each Portfolio will not:
 
      1) Invest in commodities or commodity contracts or purchase or sell real
         estate, although it may purchase and sell marketable securities of
         companies which deal in real estate or interests therein; except that
         each Portfolio except the Short-Term Federal Portfolio may invest in
         bond futures
         contracts, bond options and options on bond futures contracts to the
         extent that not more than 5% of its assets is required as margin
         deposit for futures contracts and not more than 20% of its assets is
         invested in such instruments at any time;
 
      2) Write, purchase or sell warrants, put or call options, or combinations
         thereof, except as specified above in (1);
 
      3) Invest in interests in oil, gas, or other mineral exploration or
         development programs;
 
      4) Make loans to other persons (except by (i) the purchase of the debt
         obligations in which the Portfolio is authorized to invest in
         accordance with its investment policies, and (ii) as provided under
         "Lending of Securities");
 
      5) Purchase securities on margin or sell securities short, except as
         specified above in (1);
 
      6) With respect to 75% of assets, purchase for the Portfolio more than 10%
         of the outstanding voting securities of any issuer, except securities
         issued or guaranteed by the U.S. Government or any of its agencies or
         instrumentalities or purchase securities of any issuer (except
         obligations of the U.S. Government and its agencies and
         instrumentalities) if as a result more than 5% of the value of the
         Portfolio's total assets would be invested in the securities of such
         issuer;
 
      7) Borrow money, except that the Portfolio may borrow from banks (or
         through reverse repurchase agreements), for temporary or emergency (not
         leveraging) purposes, including the meeting of redemption requests
         which might otherwise require the untimely disposition of securities,
         in an amount not exceeding 15% of the value of the Portfolio's net
         assets (including the amount borrowed and the value of any outstanding
         reverse repurchase agreements) at the time the borrowing is made.
         Whenever borrowings exceed 5% of the value of the Portfolio's net
         assets, the Portfolio will not make any additional investments;
 
      8) Pledge, mortgage or hypothecate the Portfolio's assets to an extent
         greater than 5% of the value of its total assets;
 
      9) Purchase or otherwise acquire any security if, as a result, more than
         15% of its net assets would be invested in securities that are illiquid
         (included in this limitation is the Portfolio's investment in The
         Vanguard Group, Inc.);
 
     10) Invest for the purpose of controlling the management of any company;
 
     11) Invest in securities of other investment companies, except as may be
         acquired as a part of a merger, consolidation or acquisition of assets
         or otherwise to the extent permitted by Section 12 of the Investment
         Company Act of 1940. The Portfolio will invest only in investment
         companies which have investment objectives and investment policies
         consistent with those of the Portfolio;
 
     12) Invest more than 5% of the value of the Portfolio's total assets in
         securities of companies which have (with predecessors) a record of less
         than three years' continuous operation, except investments in
         obligations guaranteed by the U.S. Government, or issued by its
         agencies or instrumentalities;
 
     13) Concentrate its investments in a particular industry, although it may
         invest up to 25% of the Portfolio's total assets (taken at value) in
         the securities of issuers, all of which conduct their
         principal business activities in the same industry, provided that: (i)
         this limitation does not apply to obligations issued or guaranteed by
         the U.S. Government, or its agencies or instrumentalities, and (ii)
         utility companies will be divided according to their services; for
         example, gas, gas transmission, electric and gas, electric, and
         telephone will each be considered a separate industry, and
 
                                       B-7
<PAGE>   144
 
         (iii) financial service companies will be classified according to the
         end users of their services, as follows: Finance-Automobiles,
         Finance-Banks, Finance-Consumers and Finance-Diversified; or
 
     14) Engage in the business of underwriting securities issued by other
         persons, except to the extent that the Portfolio may technically be
         deemed to be an underwriter under the Securities Act of 1933, as
         amended, in disposing of investment securities.
 
     The above-referenced investment limitations are considered at the time that
portfolio securities are purchased. Notwithstanding these limitations, each
Portfolio of the Fund may own all or any portion of the securities of, or make
loans to, or contribute to the costs or other financial requirements of any
company which will be wholly owned by the Fund and one or more other investment
companies and is primarily engaged in the business of providing, at cost,
management, administrative or related services to the Fund and other investment
companies. See "MANAGEMENT OF THE FUND."
 
                                       B-8
<PAGE>   145
 
                             MANAGEMENT OF THE FUND
 
DIRECTORS AND OFFICERS
 
     The Officers of the Fund manage its day-to-day operations and are
responsible to the Fund's Board of Directors. The Directors set broad policies
for the Fund and choose its Officers. The following is a list of the Directors
and Officers of the Fund and a statement of their present positions and
principal occupations during the past five years. The mailing address of the
Directors and Officers of the Fund is Post Office Box 876, Valley Forge, PA
19482.
 
JOHN C. BOGLE, (DOB: 5/8/1929)
Senior Chairman and Director*
   Senior Chairman and Director of The Vanguard Group, Inc., and of each of the
   investment companies in The Vanguard Group; Director of The Mead Corporation,
   General Accident Insurance, and Chris-Craft Industries, Inc.
 
JOHN J. BRENNAN, (DOB: 7/29/1954)
Chairman, Chief Executive Officer and Director*
   Chairman, Chief Executive Officer and Director of The Vanguard Group, Inc.,
   and of each of the investment companies in The Vanguard Group.
 
ROBERT E. CAWTHORN, (DOB: 9/28/1935)
Director
   Chairman Emeritus and Director of Rhone-Poulenc Rorer, Inc.; Managing
   Director of Global Health Care Partners/DLJ Merchant Banking Partners;
   Director of Sun Company, Inc., and Westinghouse Electric Corporation.
 
BARBARA BARNES HAUPTFUHRER, (DOB: 10/11/1928) Director
   Director of The Great Atlantic and Pacific Tea Company, IKON Office
   Solutions, Inc., Raytheon Company, Knight-Ridder, Inc., Massachusetts Mutual
   Life Insurance Co., and Ladies Professional Golf Association; and Trustee
   Emerita of Wellesley College.
 
BRUCE K. MACLAURY, (DOB: 5/7/1931)
Director
   President Emeritus of The Brookings Institution; Director of American Express
   Bank, Ltd., The St. Paul Companies, Inc. and National Steel Corporation.
 
BURTON G. MALKIEL, (DOB: 8/28/1932)
Director
   Chemical Bank Chairman's Professor of Economics, Princeton University;
   Director of Prudential Insurance Co. of America, Amdahl Corporation, Baker
   Fentress & Co., The Jeffrey Co., and Southern New England Telecommunications
   Company.
 
ALFRED M. RANKIN, JR., (DOB: 10/8/1941)
Director
   Chairman, President, Chief Executive Officer, and Director of NACCO
   Industries, Inc.; Director of The BFGoodrich Company, and The Standard
   Products Company.
 
JOHN C. SAWHILL, (DOB: 6/12/1936) Director
   President and Chief Executive Officer of The Nature Conservancy; formerly,
   Director and Senior Partner of McKinsey & Co., and President of New York
   University; Director of Pacific Gas and Electric Company, Procter & Gamble
   Company, and NACCO Industries.
 
JAMES O. WELCH, JR., (DOB: 5/13/1931)
Director
   Retired Chairman of Nabisco Brands, Inc.; retired Vice Chairman and Director
   of RJR Nabisco; Director of TECO Energy, Inc., and Kmart Corporation.
 
J. LAWRENCE WILSON, (DOB: 3/2/1936)
Director
   Chairman and Chief Executive Officer of Rohm & Haas Company; Director of
   Cummins Engine Company, and The Mead Corporation; and Trustee of Vanderbilt
   University.
 
RAYMOND J. KLAPINSKY, (DOB: 12/7/1938)
Secretary*
   Managing Director and Secretary of The Vanguard Group, Inc.; Secretary of
   each of the investment companies in The Vanguard Group.
 
RICHARD F. HYLAND, (DOB: 3/22/1937)
Treasurer*
   Treasurer of The Vanguard Group, Inc. and of each of the investment companies
   in The Vanguard Group.
 
KAREN E. WEST, (DOB: 9/13/1946)
Controller*
   Principal of The Vanguard Group, Inc.; Controller of each of the investment
   companies in The Vanguard Group.
 
- ---------------
*Officers of the Fund are "interested persons" as defined in the Investment
Company Act of 1940.
THE VANGUARD GROUP.  Vanguard Fixed Income Securities Fund is a member of The
Vanguard Group of Investment Companies. Through their jointly-owned subsidiary,
The Vanguard Group, Inc. ("Vanguard"), the Fund and the other funds in the Group
obtain at cost virtually all of their corporate management, administrative and
distribution services. Vanguard also provides investment advisory services on an
at-cost basis to certain of the Vanguard funds.
 
                                       B-9
<PAGE>   146
 
     Vanguard employs a supporting staff of management and administrative
personnel needed to provide the requisite services to the funds and also
furnishes the funds with necessary office space, furnishings and equipment. Each
fund pays its share of Vanguard's net expenses which are allocated among the
funds under methods approved by the Board of Directors (Trustees) of each fund.
In addition, each fund bears its own direct expenses, such as legal, auditing
and custodian fees.
 
     The Vanguard Group adheres to a Code of Ethics established pursuant to Rule
17j-1 under the Investment Company Act of 1940. The Code is designed to prevent
unlawful practices in connection with the purchase or sale of securities by
persons associated with Vanguard. Under Vanguard's Code of Ethics certain
Officers and employees of Vanguard who are considered access persons are
permitted to engage in personal securities transactions. However, such
transactions are subject to procedures and guidelines substantially similar to
those recommended by the mutual fund industry and approved by the U.S.
Securities and Exchange Commission.
 
     The Vanguard Group was established and operates under a Funds' Service
Agreement which was approved by the shareholders of each of the funds. The
amounts which each of the funds has invested are adjusted from time to time in
order to maintain the proportionate relationship between each fund's relative
net assets and its contribution to Vanguard's capital. At January 31, 1998, the
Fund had contributed capital of $1,802,000 to Vanguard, representing 9.0% of
Vanguard's capitalization. The Funds' Service Agreement provides for the
following arrangement: (1) each Vanguard Fund may invest a maximum of 0.40% of
its assets in Vanguard, and (2) there is no restriction on the maximum cash
investment that the Vanguard Funds may make in Vanguard.
 
     MANAGEMENT.  Corporate management and administrative services include: (1)
executive staff; (2) accounting and financial; (3) legal and regulatory; (4)
shareholder account maintenance; (5) monitoring and control of custodian
relationships; (6) shareholder reporting; and (7) review and evaluation of
advisory and other services provided to the Funds by third parties. During the
fiscal year ended January 31, 1998, the Fund's share of Vanguard's actual net
costs of operation relating to management and administrative services (including
transfer agency) totaled approximately $31,247,000.
 
     DISTRIBUTION.  Vanguard provides all distribution and marketing activities
for the funds in the Group. Vanguard Marketing Corporation, a wholly-owned
subsidiary of The Vanguard Group, Inc., acts as Sales Agent for shares of the
funds, in connection with any sales made directly to investors in the states of
Florida, Missouri, New York, Ohio, Texas and such other states as it may be
required.
 
     The principal distribution expenses are for advertising, promotional
materials and marketing personnel. Distribution services may also include
organizing and offering to the public, from time to time, one or more new
investment companies which will become members of the Group. The Directors and
Officers of Vanguard determine the amount to be spent annually on distribution
activities, the manner and amount to be spent on each fund, and whether to
organize new investment companies.
 
   
     One half of the distribution expenses of a marketing and promotional nature
is allocated among the funds based upon their relative net assets. The remaining
one half of these expenses is allocated among the funds based upon each fund's
sales for the preceding 24 months relative to the total sales of the funds as a
Group, provided, however, that no fund's aggregate quarterly rate of
contribution for distribution expenses of a marketing and promotional nature
shall exceed 125% of the average distribution expense rate for the Group, and
that no fund shall incur annual distribution expenses in excess of 20/100 of 1%
of its average month-end net assets. During the fiscal year ended January 31,
1998, the Fund paid approximately $6,377,000 of the Group's distribution and
marketing expenses, which represented an effective annual rate of .025 of 1% of
the Fund's average net assets.
    
 
     INVESTMENT ADVISORY SERVICES.  Vanguard provides investment advisory
services to the Short-Term Corporate, Short-Term Federal, Short-Term U.S.
Treasury, Intermediate-Term Corporate, Intermediate-Term U.S. Treasury and
Long-Term U.S. Treasury Portfolios of the Fund, Vanguard Money Market Reserves,
Vanguard Admiral Funds, Vanguard Institutional Index Fund, Vanguard Index Trust,
Vanguard International Equity Index Fund, Vanguard Balanced Index Fund, Vanguard
Tax-Managed Fund, the Aggressive Growth Portfolio of Vanguard Horizon Fund, the
Total International Portfolio of Vanguard STAR Fund, the REIT Index Portfolio of
Vanguard Specialized Portfolios, Vanguard Bond Index Fund, Vanguard Municipal
Bond Fund, Vanguard Florida Insured Tax-
 
                                      B-10
<PAGE>   147
 
Free Fund, Vanguard California Tax-Free Fund, Vanguard New Jersey Tax-Free Fund,
Vanguard New York Tax-Free Fund, Vanguard Ohio Tax-Free Fund, Vanguard
Pennsylvania Tax-Free Fund, several Portfolios of Vanguard Variable Insurance
Fund, a portion of Vanguard/Windsor II, a portion of Vanguard/Morgan Growth
Fund, a portion of Vanguard Explorer Fund as well as several indexed separate
accounts. These services are provided on an at-cost basis from a money
management staff employed directly by Vanguard. The compensation and other
expenses of this staff are paid by the Funds utilizing these services.
 
DIRECTOR/TRUSTEE COMPENSATION
 
   
     The individuals in the table below serve as Directors/Trustees of all
Vanguard Funds, and each fund pays a proportionate share of the
Directors'/Trustees' compensation. The Funds employ their Officers on a shared
basis, as well. However, Officers are compensated by The Vanguard Group, Inc.,
not the Funds.
    
 
     INDEPENDENT DIRECTORS/TRUSTEES.  The funds compensate their independent
Directors/Trustees -- that is, the ones who are not also Officers of the
fund -- in three ways:
 
     - The independent Directors/Trustees receive an annual fee for their
       service to the funds, which is subject to reduction based on absences
       from scheduled Board meetings.
 
     - The independent Directors/Trustees are reimbursed for the travel and
       other expenses that they incur in attending Board meetings.
 
     - Upon retirement, the independent Directors/Trustees receive an aggregate
       annual fee of $1,000 for each year served on the Board, up to fifteen
       years of service. This annual fee is paid for ten years following
       retirement, or until the Directors'/Trustees' death.
 
   
     "INTERESTED" DIRECTORS/TRUSTEES.  The funds' interested
Directors/Trustees -- Messrs. Bogle and Brennan -- receive no compensation for
their service in that capacity. However, they are paid in their role as Officers
of The Vanguard Group, Inc.
    
 
     COMPENSATION TABLE.  The following table provides compensation details for
each of the Directors. For the Fund, we list the amounts paid as compensation
and accrued as retirement benefits by the fund for each Director. In addition,
the table shows the total amount of benefits that we expect each
Director/Trustee to receive from all Vanguard funds upon retirement, and the
total amount of compensation paid to each Director/Trustee by all Vanguard
Funds. All information shown is for the fiscal year ended January 31, 1998.
 
                     VANGUARD FIXED INCOME SECURITIES FUND
                               COMPENSATION TABLE
 
<TABLE>
<CAPTION>
                             AGGREGATE     PENSION OR RETIREMENT      ESTIMATED        TOTAL COMPENSATION
                            COMPENSATION    BENEFITS ACCRUED AS    ANNUAL BENEFITS   FROM ALL VANGUARD FUNDS
    NAMES OF DIRECTORS       FROM FUND     PART OF FUND EXPENSES   UPON RETIREMENT    PAID TO DIRECTORS(2)
    ------------------      ------------   ---------------------   ---------------   -----------------------
<S>                         <C>            <C>                     <C>               <C>
John C. Bogle(1)                 None              None                   None                  None
John J. Brennan(1)               None              None                   None                  None
Barbara Barnes Hauptfuhrer     $6,544              $944                $15,000               $70,000
Robert E. Cawthorn             $6,544              $787                $13,000               $70,000
Bruce K. MacLaury              $6,963              $901                $12,000               $65,000
Burton G. Malkiel              $6,585              $633                $15,000               $70,000
Alfred M. Rankin, Jr.          $6,544              $497                $15,000               $70,000
John C. Sawhill                $6,544              $590                $15,000               $70,000
James O. Welch, Jr.            $6,544              $726                $15,000               $70,000
J. Lawrence Wilson             $6,544              $524                $15,000               $70,000
</TABLE>
 
- ---------------
(1) As "Interested Directors," Messrs. Bogle and Brennan receive no compensation
    for their service as Directors.
(2) The amounts reported in this column reflect the total compensation paid to
    each Director for his or her service as Director or Trustee of 35 Vanguard
    Funds (34 in the case of Mr. Malkiel; 28 in the case of Mr. MacLaury).
 
                                      B-11
<PAGE>   148
 
                          INVESTMENT ADVISORY SERVICES
         GNMA, LONG-TERM CORPORATE AND HIGH YIELD CORPORATE PORTFOLIOS
 
   
     The Fund employs Wellington Management Company, LLP (the "Adviser") under
an investment advisory agreement dated May 1, 1996 to manage the investment and
reinvestment of the assets of the Fund's GNMA, Long-Term Corporate and High
Yield Corporate Portfolios and to continuously review, supervise and administer
the investment program for each of these three Portfolios. The Adviser
discharges its responsibilities subject to the control of the Officers and
Directors of the Fund.
    
 
     The GNMA, Long-Term Corporate and High Yield Corporate Portfolios pay the
Adviser an aggregate fee at the end of each fiscal quarter, calculated by
applying a quarterly rate, based on the following annual percentage rates, to
the aggregate average month-end net assets of the three Portfolios for the
quarter:
 
                                 GNMA PORTFOLIO
 
<TABLE>
<CAPTION>
                         NET ASSETS                             RATE
                         ----------                             ----
<S>                                                           <C>
First $3 billion............................................   .020%
Next $3 billion.............................................   .010%
Over $6 billion.............................................   .008%
</TABLE>
 
                         LONG-TERM CORPORATE PORTFOLIO
 
<TABLE>
<CAPTION>
                         NET ASSETS                             RATE
                         ----------                             ----
<S>                                                           <C>
First $1 billion............................................   .040%
Next $1 billion.............................................   .030%
Next $1 billion.............................................   .020%
Over $3 billion.............................................   .015%
</TABLE>
 
                         HIGH-YIELD CORPORATE PORTFOLIO
 
<TABLE>
<CAPTION>
                         NET ASSETS                             RATE
                         ----------                             ----
<S>                                                           <C>
First $1 billion............................................   .060%
Next $1 billion.............................................   .040%
Next $1 billion.............................................   .030%
Over $3 billion.............................................   .025%
</TABLE>
 
     The fee, as determined above, is allocated to each Portfolio based on the
relative net assets of each.
 
     During the fiscal years ended January 31, 1996, 1997 and 1998, the three
Portfolios paid the following advisory fees to WMC:
 
<TABLE>
<CAPTION>
                                                         FISCAL YEAR ENDED JANUARY 31,
                                                      ------------------------------------
                     PORTFOLIO                           1996         1997         1998
                     ---------                           ----         ----         ----
<S>                                                   <C>          <C>          <C>
GNMA................................................  $1,181,000   $  992,000   $1,067,000
Long-Term Corporate.................................  $1,118,000   $  951,000   $  963,000
High Yield Corporate................................  $1,444,000   $1,370,000   $1,593,000
</TABLE>
 
   
     Prior to May 1, 1996, these fees were paid under the terms of a previous
investment advisory agreement which called for a higher rate of fees. The
present agreement continues until April 30, 1999, and may be continued
thereafter for successive one-year periods, as long as such continuance is
specifically approved at least annually: (a) by a vote of a majority of those
members of the Board of Directors of the Fund who are not parties to the
agreement or interested persons of any such party, cast in person at a meeting
called for the purpose of voting such approval, and (b) by the Board of
Directors of the Fund or by vote of a majority of the outstanding shares of each
of the GNMA, Long-Term Corporate and High Yield Corporate Portfolios; provided,
however, that if the holders of any one of these Portfolios fail to approve the
agreement, the Adviser may continue to serve as investment adviser to the
Portfolios which approved the agreement, and to the Portfolio which did not
approve the agreement until new arrangements have been made. The agreement may
be terminated by any Portfolio at any time, without penalty, by vote of the
Board of Directors of the Fund or by
    
 
                                      B-12
<PAGE>   149
 
vote of a majority of the outstanding shares of the Portfolio on 60 days'
written notice to the Adviser, or by the Adviser on 90 days' written notice to
the Fund. The agreement will automatically terminate in the event of its
assignment.
 
     The Fund's Board of Directors may, without the approval of shareholders,
provide for:
 
          A. The employment of a new investment adviser pursuant to the terms of
             a new advisory agreement, either as a replacement for an existing
             adviser or as an additional adviser.
 
          B. A change in the terms of an advisory agreement.
 
          C. The continued employment of an existing adviser on the same
             advisory contract terms where a contract has been assigned because
             of a change in control of the adviser.
 
     Any such change will only be made upon not less than 30 days' prior written
notice to shareholders, which shall include the information concerning the
adviser that would have normally been included in a proxy statement.
 
     Because the Adviser provides only investment advisory services to the Fund
and has no control over the Fund's expenses, the Adviser has not undertaken to
guarantee expenses of the Fund. The Officers of the Fund have worked out
alternative arrangements with state authorities which require an expense
guarantee.
 
     DESCRIPTION OF THE ADVISER.  Wellington Management Company, LLP, 75 State
Street, Boston, MA 02109, is a Massachusetts limited liability partnership, of
which the following persons are managing partners: Robert W. Doran, Duncan M.
McFarland, and John R. Ryan.
 
                   SHORT-TERM CORPORATE, SHORT-TERM FEDERAL,
             SHORT-TERM U.S. TREASURY, INTERMEDIATE-TERM CORPORATE,
     INTERMEDIATE-TERM U.S. TREASURY AND LONG-TERM U.S. TREASURY PORTFOLIOS
 
   
     The Short-Term Corporate, Short-Term Federal, Short-Term U.S. Treasury,
Intermediate-Term Corporate, Intermediate-Term U.S. Treasury and Long-Term U.S.
Treasury Portfolios receive all investment advisory services on an
"internalized," at-cost basis from an experienced investment management staff
employed directly by Vanguard. This staff also provides investment advisory
services to Vanguard Money Market Reserves, Vanguard Bond Index Fund, Vanguard
Municipal Bond Fund, Vanguard Balanced Index Fund, Vanguard Admiral Funds, the
Balanced Portfolio of Vanguard Tax-Managed Fund, Vanguard California Tax-Free
Fund, Vanguard Florida Insured Tax-Free Fund, Vanguard New Jersey Tax-Free Fund,
Vanguard Ohio Tax-Free Fund, Vanguard New York Tax-Free Fund, Vanguard
Pennsylvania Tax-Free Fund and the Money Market and High-Grade Bond Portfolios
of Vanguard Variable Insurance Fund. The compensation and other expenses of the
staff are allocated among the Portfolios of the Fund and the other Funds listed
above. During the fiscal years ended January 31, 1996, 1997 and 1998, the
Short-Term Corporate Portfolio's share of these expenses totaled approximately
$408,000, $543,000 and $698,000, respectively. During the fiscal years ended
January 31, 1996, 1997 and 1998, the Intermediate-Term Corporate Portfolio's
share of these expenses totaled approximately $28,000, $63,000 and $102,000,
respectively. During the fiscal years ended January 31, 1996, 1997 and 1998, the
Long-Term U.S. Treasury Portfolio's share of these expenses totaled
approximately $94,000, $122,000 and $136,000, respectively. During the fiscal
years ended January 31, 1996, 1997 and 1998, the Short-Term Federal Portfolio's
shares of these expenses totaled approximately $193,000, $185,000 and $205,000,
respectively. During the fiscal years ended January 31, 1996, 1997 and 1998 the
Short-Term and Intermediate-Term U.S. Treasury Portfolios' share of these
expenses totaled approximately $230,000, $288,000 and $346,000, respectively.
    
 
     The investment management staff is supervised by the senior Officers of the
Fund. The senior Officers, who are also Officers of Vanguard, Vanguard Money
Market Reserves, Vanguard Bond Index Fund, Vanguard Municipal Bond Fund,
Vanguard State Tax-Exempt Funds, and Vanguard Variable Insurance Fund, are
directly responsible to the Board of Directors of the Fund. The Board of
Directors, elected annually by shareholders, sets broad policies for the Fund
and chooses its Officers.
 
                                      B-13
<PAGE>   150
 
                             PORTFOLIO TRANSACTIONS
         GNMA, LONG-TERM CORPORATE AND HIGH YIELD CORPORATE PORTFOLIOS
 
     The investment advisory agreement authorizes Wellington Management Company,
LLP (the "Adviser") (with the approval of the Fund's Board of Directors) to
select the brokers or dealers that will execute the purchases and sales of
portfolio securities for the Fund and directs the Adviser to use its best
efforts to obtain the best available price and most favorable execution as to
all transactions for the Fund. The Adviser has undertaken to execute each
investment transaction at a price and commission which provides the most
favorable total cost or proceeds reasonably obtainable under the circumstances.
 
     In placing portfolio transactions, the Adviser will use its best judgment
to choose the broker most capable of providing the brokerage services necessary
to obtain best available price and most favorable execution. The full range and
quality of brokerage services available will be considered in making these
determinations. In those instances where it is reasonably determined that more
than one broker can offer the brokerage services needed to obtain the best
available price and most favorable execution, consideration may be given to
those brokers which supply investment research and statistical information and
provide other services in addition to execution services to the Fund and/or the
Adviser. The Adviser considers such information useful in the performance of its
obligations under the agreement but is unable to determine the amount by which
such services may reduce its expenses.
 
     The investment advisory agreement also incorporates the concepts of Section
28(e) of the Securities Exchange Act of 1934 by providing that, subject to the
approval of the Fund's Board of Directors, the Adviser may cause the Fund to pay
a broker-dealer which furnishes brokerage and research services a higher
commission than that which might be charged by another broker-dealer for
effecting the same transaction; provided that such commission is deemed
reasonable in terms of either that particular transaction or the overall
responsibilities of the Adviser to the Fund and the other Funds in the Group.
 
     Currently, it is the Fund's policy that the Adviser may at times pay higher
commissions in recognition of brokerage services felt necessary for the
achievement of better execution of certain securities transactions that
otherwise might not be available. The Adviser will only pay such higher
commissions if it believes this to be in the best interest of the Fund. Some
brokers or dealers who may receive such higher commissions in recognition of
brokerage services related to execution of securities transactions are also
providers of research information to the Adviser and/or the Fund. However, the
Adviser has informed the Fund that it will not pay higher commission rates
specifically for the purpose of obtaining research services.
 
     Some securities considered for investment by the Fund may also be
appropriate for other Funds and/or clients served by the Adviser. If purchase or
sale of securities consistent with the investment policies of the Fund and one
or more of these other Funds or clients served by the Adviser are considered at
or about the same time, transactions in such securities will be allocated among
the several Funds and clients in a manner deemed equitable by the Adviser.
 
                   SHORT-TERM CORPORATE, SHORT-TERM FEDERAL,
             SHORT-TERM U.S. TREASURY, INTERMEDIATE-TERM CORPORATE,
    INTERMEDIATE-TERM U.S. TREASURY, AND LONG-TERM U.S. TREASURY PORTFOLIOS
 
     Brokers or dealers who execute transactions for the Short-Term Corporate,
Short-Term Federal, Short-
Term U.S. Treasury, Intermediate-Term Corporate, Intermediate-Term U.S.
Treasury, and Long-Term U.S.
Treasury Portfolios are selected by Vanguard's investment management staff,
which is responsible for using its best efforts to obtain the best available
price and most favorable execution for each transaction. Principal transactions
are made directly with issuers, underwriters and market makers and usually do
not involve brokerage commissions, although underwriting commissions and dealer
mark-ups may be involved. Brokerage transactions are placed with brokers deemed
most capable of providing favorable terms; where more than one broker can offer
such terms, consideration may be given to brokers who provide the staff with
research and statistical information.
 
     Vanguard's investment management staff may occasionally make
recommendations to other Vanguard Funds or clients which result in their
purchasing or selling securities simultaneously with the Portfolios. As a
result, the demand for securities being purchased or the supply of securities
being sold may increase, and this
 
                                      B-14
<PAGE>   151
 
could have an adverse effect on the price of those securities. It is the staff's
policy not to favor one client over another in making recommendations or placing
an order. If two or more clients are purchasing a given security on the same day
from the same broker-dealer, such transactions may be averaged as to price.
 
                                 ALL PORTFOLIOS
 
     Since the Fund does not market its shares through intermediary brokers or
dealers, it is not the Fund's practice to allocate brokerage or principal
business on the basis of sales of its shares which may be made through such
firms. However, the Fund may place portfolio orders with qualified brokers or
dealers who recommend the shares of the Fund to their clients and may, when a
number of brokers and dealers can provide comparable best price and execution on
a particular transaction, consider the sale of shares by a broker or dealer in
selecting among qualified brokers or dealers.
 
     The total brokerage commission paid by the Fund for the fiscal year ended
January 31, 1996 was $4,500. The Fund did not incur any brokerage commissions
for the fiscal years ended January 31, 1997 and January 31, 1998.
 
                             YIELD AND TOTAL RETURN
 
     The yield* of each Portfolio of the Fund for the 30-day period ended
January 31, 1998 is set forth below:
 
<TABLE>
<S>                                                           <C>
Short-Term U.S. Treasury Portfolio..........................  5.25%
Short-Term Federal Portfolio................................  5.40%
Short-Term Corporate Portfolio -- Investor Shares...........  5.83%
Short-Term Corporate Portfolio -- Institutional Shares......  5.95%
Intermediate-Term U.S. Treasury Portfolio...................  5.43%
GNMA Portfolio..............................................  6.68%
Long-Term U.S. Treasury Portfolio...........................  5.72%
Long-Term Corporate Portfolio...............................  6.45%
High Yield Corporate Portfolio..............................  8.03%(1)
Intermediate-Term Corporate Portfolio.......................  6.18%
</TABLE>
 
- ---------------
   
     *   The yield for each Portfolio of the Fund is calculated daily. Further,
         in calculating the yield, the premiums and discounts on asset-backed
         securities are not amortized.
    
 
     (1) Yield for the High Yield Corporate Portfolio reflects a premium based
         on the possibility that interest payments on some bonds may be reduced
         or eliminated. Also, since bonds with higher interest coupons may be
         replaced by bonds with lower coupons, income dividends are subject to
         reduction.
 
     The average annual total return of each Portfolio of the Fund for the one-,
five- and ten-year periods ending January 31, 1998 is set forth below:
 
<TABLE>
<CAPTION>
                                                    1 YEAR ENDED   5 YEARS ENDED   10 YEARS ENDED
                                                      1/31/98         1/31/98         1/31/98
                                                    ------------   -------------   --------------
<S>                                                 <C>            <C>             <C>
Short-Term U.S. Treasury Portfolio................      7.11%           5.60%           6.29%*
Short-Term Federal Portfolio......................      7.06%           5.73%           7.38%*
Short-Term Corporate Portfolio -- Investor
  Shares..........................................      7.53%           6.08%           7.81%
Short-Term Corporate Portfolio -- Institutional
  Shares..........................................      2.79%*            N/A             N/A
GNMA Portfolio....................................      9.86%           7.12%           8.93%
Intermediate-Term U.S. Treasury Portfolio.........     10.78%           7.14%           8.38%*
Intermediate-Term Corporate Portfolio.............     10.24%           6.82%*            N/A
Long-Term U.S. Treasury Portfolio.................     16.85%           9.50%          10.27%
Long-Term Corporate Portfolio.....................     15.52%           9.24%          10.56%
High Yield Corporate Portfolio....................     13.14%          10.96%          10.36%
</TABLE>
 
- ---------------
     * Since inception: Short-Term Federal Portfolio -- December 31, 1987
                        Short-Term U.S. Treasury and Intermediate-Term
                        U.S. Treasury Portfolios -- October 28, 1991
                        Intermediate-Term Corporate -- November 1, 1993
   
                        Short-Term Corporate Portfolio -- Institutional
                        Shares -- September 30, 1997
    
 
                                      B-15
<PAGE>   152
 
                              FINANCIAL STATEMENTS
 
     The Fund's financial statements as of and for the fiscal year ended January
31, 1998, appearing in the Fund's 1998 Annual Report to Shareholders, and the
reports thereon of Price Waterhouse LLP, independent accountants, also appearing
in the Annual Report, are incorporated by reference in this Statement of
Additional Information.
 
                              PERFORMANCE MEASURES
 
     Vanguard may use reprinted material discussing The Vanguard Group, Inc. or
any of the member funds of The Vanguard Group of Investment Companies.
 
     Each of the investment company members of the Vanguard Group, including
each Portfolio of Vanguard Fixed Income Securities Fund, Inc., may, from time to
time, use one or more of the following unmanaged indices for comparative
performance purposes.
 
STANDARD AND POOR'S 500 COMPOSITE STOCK PRICE INDEX -- is a well diversified
list of 500 companies
representing the U.S. Stock Market.
 
STANDARD & POOR'S MIDCAP 400 INDEX -- is composed of 400 medium sized domestic
stocks.
 
STANDARD & POOR'S SMALLCAP 600/BARRA VALUE INDEX -- contains stocks of the S&P
SmallCap 600 Index which have a lower than average price-to-book ratio.
 
STANDARD & POOR'S SMALLCAP 600/BARRA GROWTH INDEX -- contains stocks of the S&P
SmallCap 600 Index which have a higher than average price-to-book ratio.
 
RUSSELL 1000 VALUE INDEX -- consists of the stocks in the Russell 1000 Index
(comprising the 1,000 largest U.S.-based companies measured by total market
capitalization) with the lowest price-to-book ratios, comprising 50% of the
market capitalization of the Russell 1000.
 
WILSHIRE 5000 EQUITY INDEX -- consists of more than 7,000 common equity
securities, covering all stocks in the U.S. for which daily pricing is
available.
 
WILSHIRE 4500 EQUITY INDEX -- consists of all stocks in the Wilshire 5000 except
for the 500 stocks in the Standard and Poor's 500 Index.
 
MORGAN STANLEY CAPITAL INTERNATIONAL EAFE INDEX -- is an arithmetic, market
value-weighted average of the performance of over 900 securities listed on the
stock exchanges of countries in Europe, Australasia and the Far East.
 
GOLDMAN SACHS 100 CONVERTIBLE BOND INDEX -- currently includes 71 bonds and 29
preferreds. The original list of names was generated by screening for
convertible issues of $100 million or greater in market capitalization. The
index is priced monthly.
 
LEHMAN BROTHERS GNMA INDEX -- includes pools of mortgages originated by private
lenders and guaranteed by the mortgage pools of the Government National Mortgage
Association.
 
LEHMAN LONG-TERM TREASURY BOND INDEX -- is composed of all bonds covered by the
Shearson Lehman Hutton Treasury Bond Index with maturities of 10 years or
greater.
 
MERRILL LYNCH CORPORATE & GOVERNMENT BOND INDEX -- consists of over 4,500 U.S.
Treasury, agency and investment grade corporate bonds.
 
LEHMAN CORPORATE (BAA) BOND INDEX -- all publicly offered fixed-rate,
nonconvertible domestic corporate bonds rated Baa by Moody's, with a maturity
longer than 1 year and with more than $25 million outstanding. This index
includes over 1,000 issues.
 
LEHMAN BROTHERS LONG-TERM CORPORATE BOND INDEX -- is a subset of the Lehman
Corporate Bond Index covering all corporate, publicly issued, fixed-rate,
nonconvertible U.S. debt issues rated at least Baa, with at least $50 million
principal outstanding and maturity greater than 10 years.
                                      B-16
<PAGE>   153
 
MERRILL LYNCH DRD -- ELIGIBLE INDEX -- includes preferred stock issues which are
eligible for the corporate dividends-received deduction.
 
LEHMAN BROTHERS HIGH YIELD INDEX -- includes all fixed income securities having
a maximum quality rating of Ba1 (including defaulted issues; a minimum
outstanding of $100mm, and at least 1 year to maturity; payment-in-kind bonds
and Eurobonds are excluded.
 
BOND BUYER MUNICIPAL BOND INDEX -- is a yield index on current coupon high-grade
general obligation municipal bonds.
 
NASDAQ INDUSTRIAL INDEX -- is composed of more than 3,000 industrial issues. It
is a value-weighted index calculated on price change only and does not include
income.
 
COMPOSITE INDEX -- 70% Standard & Poor's 500 Index and 30% NASDAQ Industrial
Index.
 
COMPOSITE INDEX -- 65% Standard & Poor's 500 Index and 35% Lehman Long-Term
Corporate AA or Better Bond Index.
 
COMPOSITE INDEX -- 65% Lehman Long-Term Corporate AA or Better Bond Index and a
35% weighting in a blended equity composite (75% Standard & Poor's/BARRA Value
Index, 12.5% Standard & Poor's Utilities Index and 12.5% Standard & Poor's
Telephone Index).
 
LEHMAN LONG-TERM CORPORATE AA OR BETTER BOND INDEX -- consists of all publicly
issued, fixed rate, nonconvertible investment grade, dollar-denominated,
SEC-registered corporate debt rated AA or AAA.
 
LEHMAN BROTHERS AGGREGATE BOND INDEX -- is a market-weighted index that contains
individually priced U.S. Treasury, agency, corporate, and mortgage pass-through
securities corporate rated Baa- or better. The Index has a market value of over
$4 trillion.
 
LEHMAN BROTHERS MUTUAL FUND SHORT (1-5) GOVERNMENT/CORPORATE INDEX -- is a
market-weighted index that contains individually priced U.S. Treasury, agency,
and corporate investment grade bonds rated BBB- or better with maturities
between 1 and 5 years. The index has a market value of over $1.6 trillion.
 
LEHMAN BROTHERS MUTUAL FUND INTERMEDIATE (5-10) GOVERNMENT/CORPORATE INDEX -- is
a market-weighted index that contains individually priced U.S. Treasury, agency,
and corporate securities rated BBB- or better with maturities between 5 and 10
years. The index has a market value of over $700 billion.
 
LEHMAN BROTHERS LONG (10+) GOVERNMENT/CORPORATE INDEX -- is a market-weighted
index that contains individually priced U.S. Treasury, agency, and corporate
securities rated BBB- or better with maturities greater than 10 years. The index
has a market value of over $900 billion.
 
LEHMAN BROTHERS INTERMEDIATE-TERM CORPORATE BOND INDEX -- consists of all
investment grade corporate debt with maturities of 5 to 10 years.
 
LIPPER GENERAL EQUITY FUND AVERAGE -- an industry benchmark of average general
equity funds with similar investment objectives and policies, as measured by
Lipper Analytical Services, Inc.
 
LIPPER FIXED INCOME FUND AVERAGE -- an industry benchmark of average fixed
income funds with similar investment objectives and policies, as measured by
Lipper Analytical Services, Inc.
 
                               OTHER DEFINITIONS
 
     Marketing literature for the Portfolios of Vanguard Fixed Income Securities
Fund, Inc., may from time to time refer to or discuss a Portfolio's DURATION.
Duration is the weighted average life of a Portfolio's debt instruments measured
on a present-value basis; it is generally superior to average weighted maturity
as a measure of a Portfolio's potential volatility due to changes in interest
rates.
 
     Unlike a Portfolio's average weighted maturity, which takes into account
only the stated maturity date of the Portfolio's debt instruments, duration
represents a weighted average of both interest and principal payments,
discounted by the current yield-to-maturity of the securities held. For example,
a four-year, zero-
 
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coupon bond, which pays interest only upon maturity (along with principal), has
both a maturity and duration of 4 years. However, a four-year bond priced at par
with an 8% coupon has a maturity of 4 years but a duration of 3.6 years (at an
8% yield), reflecting the bond's earlier payment of interest.
 
     In general, a bond with a longer duration will fluctuate more in price than
a bond with a shorter duration. Also, for small changes in interest rates,
duration serves to approximate the resulting change in a bond's price. For
example, a 1% change in interest rates will cause roughly a 4% move in the price
of a zero-coupon bond with a 4-year duration, while an 8% coupon bond (with a
3.6 year duration) will change by approximately 3.6%.
 
               APPENDIX -- DESCRIPTION OF SECURITIES AND RATINGS
 
I. DESCRIPTION OF BOND RATINGS
 
     Excerpts from Moody's Investors Service, Inc., ("Moody's") description of
its four highest bond ratings: AAA -- judged to be the best quality. They carry
the smallest degree of investment risk; AA -- judged to be of high quality by
all standards. Together with the Aaa group they comprise what are generally
known as high grade bonds; A -- possess many favorable investment attributes and
are to be considered as "upper medium grade obligations"; BAA -- 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. BA -- judged to
have speculative elements; their future cannot be considered as well assured;
B -- generally lack characteristics of the desirable investment; 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 -- speculative in a high
degree; often in default; C -- lowest rated class of bonds; regarded as having
extremely poor prospects.
 
     Moody's also supplies numerical indicators 1, 2 and 3 to rating categories.
The modifier 1 indicates that the security is in the higher end of its rating
category; the modifier 2 indicates a mid-range ranking; and 3 indicates a
ranking toward the lower end of the category.
 
     Excerpts from Standard & Poor's Corporation ("S&P") description of its five
highest bond ratings: AAA -- highest grade obligations. Capacity to pay interest
and repay principal is extremely strong; AA -- also qualify as high grade
obligations. A very strong capacity to pay interest and repay principal and
differs from AAA issues only in small degree; A -- regarded as upper medium
grade. They have a strong capacity to pay interest and repay principal although
they are somewhat susceptible to the adverse effects of changes in circumstances
and economic conditions than debt in higher rated categories; BBB -- 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. This group is the lowest which qualifies for commercial bank
investment. BB, B, CCC, CC -- predominately speculative with respect to capacity
to pay interest and repay principal in accordance with terms of the obligation;
BB indicates the lowest degree of speculation and CC the highest.
 
     S&P applies indicators "+," no character, and "-" to its rating categories.
The indicators show relative standing within the major rating categories.
 
II. DESCRIPTION OF GNMA MORTGAGE-BACKED CERTIFICATES
 
     GNMA (Government National Mortgage Association) Certificates are
mortgage-backed securities. The Certificates evidence part ownership of a pool
of mortgage loans. The Certificates which the GNMA Portfolio will purchase are
of the "modified pass-through" type. "Modified pass-through" Certificates
entitle the holder to receive all interest and principal payments owed on the
mortgage pool, net of fees paid to the "issuer" and GNMA, regardless of whether
or not the mortgagor actually makes the payment.
 
     THE GNMA GUARANTEE  The National Housing Act authorizes GNMA to guarantee
the timely payment of principal of and interest on securities backed by a group
(or pool) of mortgages insured by FHA or FHMA, or
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guaranteed by VA. The GNMA guarantee is backed by the full faith and credit of
the U.S. Government. GNMA is also empowered to borrow without limitation from
the U.S. Treasury if necessary to make any payments required under its
guarantee.
 
     THE LIFE OF GNMA CERTIFICATES  The average life of GNMA Certificates is
likely to be substantially less than the original maturity of the mortgage pools
underlying the securities. Prepayments of principal by mortgagors and mortgage
foreclosures will usually result in the return of the greatest part of principal
invested well before the maturity of the mortgages in the pool. (Note: Due to
the GNMA guarantee, foreclosures impose no risk to principal investment.) As
prepayment rates of individual mortgage pools will vary widely, it is not
possible to accurately predict the average life of a particular issue of GNMA
Certificates. However, statistics published by the FHA are normally used as an
indicator of the expected average life of GNMA Certificates. These statistics
indicate that the average life of single-family dwelling mortgages with 25-30
year maturities, the type of mortgages backing the vast majority of GNMA
Certificates, is approximately 12 years. For this reason, it is standard
practice to treat GNMA Certificates as 30-year mortgage-backed securities which
prepay fully in the twelfth year.
 
     YIELD CHARACTERISTICS OF GNMA CERTIFICATES  The coupon rate of interest of
GNMA Certificates is lower than the interest rate paid on the VA-guaranteed or
FHA-insured mortgages underlying the Certificates, but only by the amount of the
fees paid to GNMA and the issuer. For the most common type of mortgage pool,
containing single-family dwelling mortgages. GNMA receives an annual fee of 0.06
of 1% of the outstanding principal for providing its guarantee, and the issuer
is paid an annual fee of 0.44 of 1% for assembling the mortgage pool and for
passing through monthly payments of interest and principal to Certificate
holders.
 
     The coupon rate by itself, however, does not indicate the yield which will
be earned on the Certificates for the following reasons:
 
     1. Certificates may be issued at a premium or discount, rather than at par.
 
     2. After issuance, Certificates may trade in the secondary market at a
        premium or discount.
 
     3. Interest is earned monthly, rather than semiannually as for traditional
        bonds. Monthly compounding has the effect of raising the effective yield
        earned on GNMA Certificates.
 
     4. The actual yield of each GNMA Certificate is influenced by the
        prepayment experience of the mortgage pool underlying the Certificate.
        That is, if mortgagors pay off their mortgages early, the principal
        returned to Certificate holders may be reinvested at more or less
        favorable rates.
 
     In quoting yields for GNMA Certificates, the standard practice is to assume
that the Certificates will have a 12-year life. Compared on this basis, GNMA
Certificates have historically yielded roughly .25 of 1% more than high-grade
corporate bonds and .50 of 1% more than U.S. Government and U.S. Government
Agency bonds. As the life of individual pools may vary widely, however, the
actual yield earned on any issue of GNMA Certificates may differ significantly
from the yield estimated on the assumption of a 12-year life.
 
     MARKET FOR GNMA CERTIFICATES  Since the inception of the GNMA
Mortgage-Backed Securities program in
1970, the amount of GNMA Certificates outstanding has grown rapidly. The size of
the market and the active
participation in the secondary market by securities dealers and many types of
investors make the GNMA
Certificates a highly liquid instrument. Prices of GNMA Certificates are readily
available from securities dealers and depend on, among other things, the level
of market rates, the Certificate's coupon rate and the prepay-
ment experience of the pool of mortgages backing each Certificate.
 
     "WHEN ISSUED" SECURITIES  GNMA securities may be purchased and sold on a
when issued and delayed delivery basis. Delayed delivery or when issued
transactions arise when securities are purchased or sold by a Portfolio with
payment and delivery taking place in the future in order to secure what is
considered to be an advantageous price and yield to the Portfolio at the time of
entering into the transaction. When the Portfolio engages in "when issued" and
delayed delivery transactions, the Portfolio relies on the buyer or seller, as
the case may be, to consummate the sale. Failure to do so may result in the
Portfolio missing the opportunity of obtaining a price or yield considered to be
advantageous. When issued and delayed delivery transactions may be expected to
occur a month or more before delivery is due. However, no payment or delivery is
made by the
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Portfolio until it receives payment or delivery from the other party to the
transaction. A separate account of liquid assets equal to the value of such
purchase commitments will be maintained until payment is made. To the extent the
Portfolio engages in "when issued" and delayed delivery transactions, it will do
so for the purpose of acquiring securities consistent with its investment
objective and policies and not for the purpose of investment leverage.
 
III. COMMERCIAL PAPER
 
     A Portfolio may invest in commercial paper (including variable amount
master demand notes) rated A-1 or better by Standard & Poor's or Prime-1 by
Moody's, or, if unrated, issued by a corporation having an outstanding unsecured
debt issue rated A or better by Moody's or by Standard & Poor's. Commercial
paper refers to short-term, unsecured promissory notes issued by corporations to
finance short-term credit needs. Commercial paper is usually sold on a discount
basis and has a maturity at the time of issuance not exceeding nine months.
Variable amount master demand notes are demand obligations that permit the
investment of fluctuating amounts at varying market rates of interest pursuant
to arrangement between the issuer and a commercial bank acting as agent for the
payees of such notes, whereby both parties have the right to vary the amount of
the outstanding indebtedness on the notes. Because variable amount master demand
notes are direct lending arrangements between a lender and a borrower, it is not
generally contemplated that such instruments will be traded, and there is no
secondary market for these notes, although they are redeemable (and thus
immediately repayable by the borrower) at face value, plus accrued interest, at
any time. In connection with the Portfolio's investment in variable amount
master demand notes, Vanguard's investment management staff will monitor, on an
ongoing basis, the earning power, cash flow and other liquidity ratios of the
issuer, and the borrower's ability to pay principal and interest on demand.
 
   
     Commercial paper rated A-1 by Standard & Poor's has the following
characteristics: (1) liquidity ratios are adequate to meet cash requirements;
(2) long-term senior debt is rated "A" or better; (3) the issuer has access to
at least two additional channels of borrowing; (4) basic earnings and cash flow
have an upward trend with allowance made for unusual circumstances; (5)
typically, the issuer's industry is well established and the issuer has a strong
position within the industry; and (6) the reliability and quality of management
are unquestioned. Relative strength or weakness of the above factors determine
whether the issuer's commercial paper is A-1, A-2 or A-3. The rating Prime-1 is
the highest commercial paper rating assigned by Moody's. Among the factors
considered by Moody's in assigning ratings are the following: (1) evaluation of
the management of the issuer; (2) economic evaluation of the issuer's industry
or industries and the appraisal of speculative-type risks which may be inherent
in certain areas; (3) evaluation of the issuer's products in relation to
completion and customer acceptance; (4) liquidity; (5) amount and quality of
long-term debt; (6) trend of earnings over a period of ten years; (7) financial
strength of a parent company and the relationships which exist with the issuer;
and (8) recognition by the management of obligations which may be present or may
arise as a result of public interest questions and preparations to meet such
obligations.
    
 
IV. U.S. GOVERNMENT SECURITIES
 
     The term "U.S. Government securities" refers to a variety of securities
which are issued or guaranteed by the United States Treasury, by various
agencies of the United States Government, and by various instrumentalities which
have been established or sponsored by the United States Government. The term
also refers to "repurchase agreements" collateralized by such securities.
 
     U.S. Treasury securities are backed by the "full faith and credit" of the
United States. Securities issued or guaranteed by Federal agencies and U.S.
Government-sponsored instrumentalities may or may not be backed by the full
faith and credit of the United States. In the case of securities not backed by
the full faith and credit of the United States, the investor must look
principally to the agency or instrumentality issuing or guaranteeing the
obligation for ultimate repayment, and may not be able to assert a claim against
the United States itself in the event the agency or instrumentality does not
meet its commitment.
 
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     Some of the U.S. Government agencies that issue or guarantee securities
include the Export-Import Bank of the United States, Farmers Home
Administration, Federal Housing Administration, Maritime Administration, Small
Business Administration, and The Tennessee Valley Authority.
 
     An instrumentality of the U.S. Government is a government agency organized
under Federal charter with government supervision. Instrumentalities issuing or
guaranteeing securities include, among others, Federal Home Loan Banks, the
Federal Land Banks, Central Bank for Cooperatives, Federal Intermediate Credit
Banks, and the Federal National Mortgage Association.
 
V. BANK OBLIGATIONS
 
   
     Time deposits are non-negotiable deposits maintained in a banking
institution for a specified period of time at a stated interest rate.
Certificates of deposit are negotiable short-term obligations of commercial
banks. Variable rate certificates of deposit are certificates of deposit on
which the interest rate is periodically adjusted prior to their stated maturity
based upon a specified market rate. As a result of these adjustments, the
interest rate on these obligations may be increased or decreased periodically.
Frequently, dealers selling variable rate certificates of deposit to a Portfolio
will agree to repurchase such instruments, at the Portfolio's option, at par on
or near the coupon dates. The dealers' obligations to repurchase these
instruments are subject to conditions imposed by various dealers; such
conditions typically are the continued credit standing of the issuer and the
existence of reasonably orderly market conditions. A Portfolio is also able to
sell variable rate certificates of deposit in the secondary market. Variable
rate certificates of deposit normally carry a higher interest rate than
comparable fixed-rate certificates of deposit. A bankers' acceptance is a time
draft drawn on a commercial bank by a borrower usually in connection with an
international commercial transaction (to finance the import, export, transfer or
storage of goods). The borrower is liable for payment as well as the bank, which
unconditionally guarantees to pay the draft at its face amount on the maturity
date. Most acceptances have maturities of six months or less and are traded in
the secondary markets prior to maturity.
    
 
VI. SHORT AND INTERMEDIATE TERM CORPORATE DEBT SECURITIES
 
     Outstanding non-convertible corporate debt securities (e.g. bonds and
debentures) which are rated Baa3 or better either by Moody's or BBB- or better
by Standard & Poor's are considered investment grade.
 
VII. FOREIGN INVESTMENTS
 
   
     The Short-Term Corporate, Intermediate-Term Corporate, High Yield Corporate
and Long-Term Corporate Portfolios may invest in the securities (payable in U.S.
dollars) of foreign issues and in the securities of foreign branches of U.S.
banks such as negotiable certificates of deposit (Eurodollars). Because these
Portfolios invest in such securities, investment in these Portfolios involves
investment risks that are different in some respects from an investment in a
fund which invests only in debt obligations of U.S. issuers. Such risks may
include future political and economic developments, the possible imposition of
withholding taxes on interest income payable on the securities held, possible
seizure or nationalization of foreign deposits, the possible establishment of
exchange controls or the adoption of other restrictions by foreign governments
which may adversely affect the payment of principal and interest on securities
held by the Portfolios, difficulty in obtaining and enforcing court judgments
abroad, the possibility of restrictions on investments in other jurisdictions,
reduced levels of government regulation of securities markets in foreign
countries, and difficulties in effecting the repatriation of capital invested
abroad.
    
 
VIII. ZERO COUPON TREASURY BONDS
 
     All Portfolios may invest in zero coupon Treasury bonds, a term used to
describe U.S. Treasury notes and bonds which have been stripped of their
unmatured interest coupons, or the coupons themselves, and also receipts or
certificates representing interest in such stripped debt obligations and
coupons. The timely payment of coupon interest and principal on these
instruments remains guaranteed by the "full faith and credit" of the United
States Government.
 
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<PAGE>   158
 
     A zero coupon bond does not pay interest. Instead, it is issued at a
substantial discount to its "face value" -- what it will be worth at maturity.
The difference between a security's issue or purchase price and its face value
represents the imputed interest an investor will earn if the security is held
until maturity. For tax purposes, a portion of this imputed interest is deemed
as income received by zero coupon bondholders each year. The Fund, which expects
to qualify as a regulated investment company, intends to pass along such
interest as a component of a Portfolio's distributions of net investment income.
 
     Zero coupon bonds may offer investors the opportunity to earn higher yields
than those available on U.S. Treasury bonds of similar maturity. However, zero
coupon bond prices may also exhibit greater price volatility than ordinary debt
securities because of the manner in which their principal and interest is
returned to the investor.
 
IX. COLLATERALIZED MORTGAGE OBLIGATIONS
 
     The Short-Term Federal, Short-Term Corporate, Intermediate-Term Corporate
and the Short-, Intermedi-
ate- and Long-Term U.S. Treasury Portfolios may invest in collateralized
mortgage obligations (CMOs), bonds
that are collateralized by whole loan mortgages or mortgage pass-through
securities. The bonds issued in a
CMO deal are divided into groups, and each group of bonds is referred to as a
"tranche". Under the CMO
structure, the cash flows generated by the mortgages or mortgage pass-through
securities in the collateral
pool are used to first pay interest and then pay principal to the CMO
bondholders. The bonds issued under a CMO structure are retired sequentially as
opposed to the pro rata return of principal found in traditional pass-through
obligations. Subject to the various provisions of individual CMO issues, the
cash flow generated by the underlying collateral (to the extent it exceeds the
amount required to pay the stated interest) is used to retire the bonds. Under
the CMO structure, the repayment of principal among the different tranches is
prioritized in accordance with the terms of the particular CMO issuance. The
"fastest-pay" tranche of bonds, as specified in the prospectus for the issuance,
would initially receive all principal payments. When that tranche of bonds is
retired, the next tranche, or tranches, in the sequence, as specified in the
prospectus, receive all of the principal payments until they are retired. The
sequential retirement of bond groups continues until the last tranche, or group
of bonds, is retired. Accordingly, the CMO structure allows the issuer to use
cash flows of long maturity, monthly-pay collateral to formulate securities with
short, intermediate and long final maturities and expected average lives. The
primary risks involved in any mortgage security, such as a CMO issuance, is its
exposure to prepayment risk. To the extent a particular tranche is exposed to
this risk, the bondholder is generally compensated in the form of higher yield.
In order to provide security, in addition to the underlying collateral, many CMO
issues also include minimum reinvestment rate and minimum sinking-fund
guarantees. Typically, the Portfolios will invest in those CMOs that most
appropriately reflect their average maturities and market risk profiles.
Consequently, the Short-Term Portfolios invest only in CMOs with highly
predictable short-term average maturities. Similarly, the Intermediate- and
Long-Term Treasury Portfolios will invest in those CMOs that carry market risks
consistent with intermediate- and long-term bonds.
 
X. REAL ESTATE
 
     The GNMA Portfolio may invest in real estate investment conduits
("REMICs"). REMICs, which were authorized under the Tax Reform Act of 1986, are
private entities formed for the purpose of holding a fixed pool of mortgages
secured by an interest in real property. REMICs are similar to CMOs in that they
issue multiple classes of securities. A REMIC is a CMO that qualifies for
special tax treatment under the Internal Revenue Code and invests in certain
mortgages principally secured by interests in real property. Investors may
purchase beneficial interests in REMICs, which are known as "regular" interests,
or "residual" interests. Guaranteed REMIC pass-through certificates ("REMIC
Certificates") issued by FNMA or FHLMC represent beneficial ownership interests
in a REMIC trust consisting principally of mortgage loans or FNMA, FHLMC or
GNMA-guaranteed mortgage pass-through certificates. For FHLMC REMIC
Certificates, FHLMC guarantees the timely payment of interest, and also
guarantees the payment of principal as payments are required to be made on the
underlying mortgage participation certificates. FNMA REMIC Certificates are
issued and guaranteed as to timely distribution of principal and interest by
FNMA.
 
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