<PAGE>
[logo: MFS
INVESTMENT MANAGEMENT
75 YEARS
WE INVENTED THE MUTUAL FUND[RegTM]]
- -------------------------------------------
MFS[RegTM] VARIABLE INSURANCE TRUST(SM)
- -------------------------------------------
M A Y 1 , 1 9 9 9 Prospectus
MFS[RegTM] RESEARCH SERIES
MFS[RegTM] NEW DISCOVERY SERIES
MFS[RegTM] GROWTH SERIES
- --------------------------------------------------------------------------------
This Prospectus describes three of the series of the MFS Variable Insurance
Trust (referred to as the trust):
1. MFS Research Series seeks to provide long-term growth of capital and future
income (referred to as the Research Series);
2. MFS New Discovery Series seeks capital appreciation (referred to as the New
Discovery Series); and
3. MFS Growth Series seeks to provide long-term growth of capital and future
income rather than current income (referred to as the Growth Series);
The Securities and Exchange Commission has not approved the series' shares or
determined whether this prospectus is accurate or complete. Anyone who tells
you otherwise is committing a crime.
<PAGE>
<TABLE>
<CAPTION>
TABLE OF CONTENTS Page
<S> <C> <C>
I Expense Summary ............................................ 1
II Risk Return Summary ........................................ 3
1. Research Series ........................................ 3
2. New Discovery Series ................................... 5
3. Growth Series .......................................... 7
III Certain Investment Strategies and Risks .................... 9
IV Management of the Series ................................... 9
V Description of Shares ...................................... 9
VI Other Information .......................................... 10
VII Financial Highlights ....................................... 11
Appendix A -- Investment Techniques and Practices .......... A-1
</TABLE>
<PAGE>
The trust offers shares of its 15 series to separate accounts established
by insurance companies in order to serve as investment vehicles for
variable annuity and variable life insurance contracts and to qualified
pension and retirement plans. Each of these series is managed by
Massachusetts Financial Services Company (referred to as MFS or the
adviser). Three of the series are described below.
- ---------------------
I EXPENSE SUMMARY
- ---------------------
> Expense Table
This table describes the expense that you may pay when you hold shares of the
series. These fees and expenses do not take into account the fees and
expenses imposed by insurance companies through which your investment in a
series may be made.
Annual Series Operating Expenses (expenses that are deducted from a series'
assets):
<TABLE>
<CAPTION>
New
Research Discovery Growth
Series Series Series
------ ------ ------
<S> <C> <C> <C>
Management Fee .................................... 0.75% 0.90% 0.75%
Other Expenses(1) ................................. 0.11% 4.32% 3.28%
---- ----- -----
Total Annual Series Operating Expenses(1) ......... 0.86% 5.22% 4.03%
Expense Reimbursement ............................ -- (4.05)%(2) (3.03)%(2)
---- ----- -----
Net Expenses(1) .................................. 0.86% 1.17% 1.00%
</TABLE>
-----------
(1) Each series has an expense offset arrangement which reduces the series'
custodian fee based upon the amount of cash maintained by the series with
its custodian and dividend disbursing agent. Each series may enter into
other such arrangements and directed brokerage arrangements, which would
also have the effect of reducing the series' expenses. Expenses do not
take into account these expense reductions, and are therefore higher than
the actual expenses of the series.
(2) MFS has contractually agreed to bear expenses for these series, subject
to reimbursement by these series, such that each such series' "Other
Expenses" shall not exceed 0.25% of the average daily net assets of the
series during the current fiscal year. The payments made by MFS on behalf
of each series under this arrangement are subject to reimbursement by the
series to MFS, which will be accomplished by the payment of an expense
reimbursement fee by the series to MFS computed and paid monthly at a
percentage of the series' average daily net assets for its then current
fiscal year, with a limitation that immediately after such payment the
series' "Other Expenses" will not exceed the percentage set forth above
for that series. The obligation of MFS to bear a series' "Other Expenses"
pursuant to this arrangement, and the series' obligation to pay the
reimbursement fee to MFS, terminates on the earlier of the date on which
payments made by the series' equal the prior payment of such reimbursable
expenses by MFS, or May 1, 2001, in the case of the New Discovery Series
and May 1, 2002 in the case of the Growth Series. MFS may, in its
discretion, terminate this contractual arrangement at an earlier date,
provided that the arrangement will continue for each series until at
least May 1, 2000, unless terminated with the consent of the board of
trustees which oversees the series.
1
<PAGE>
> Example of Expenses
These examples are intended to help you compare the cost of investing in the
series with the cost of investing in other mutual funds. These examples do
not take into account the fees and expenses imposed by insurance companies
through which your investment in a series may be made.
The examples assume that:
o You invest $10,000 in the series for the time periods indicated and you
redeem your shares at the end of the time periods;
o Your investment has a 5% return each year and dividends and other
distributions are reinvested; and
o The series' operating expenses remain the same.
Although your actual costs may be higher or lower, under these assumptions
your costs would be:
<TABLE>
<CAPTION>
Period
-------------------------------------------------
Series 1 Year 3 Years 5 Years 10 Years
------------------------------------------------------------------------
<S> <C> <C> <C> <C>
Research Series $ 88 $ 274 $ 477 $1,061
New Discovery Series 119 1,201 2,278 4,949
Growth Series 102 948 -- --
</TABLE>
2
<PAGE>
- ---------------------------
II RISK RETURN SUMMARY
- ---------------------------
Investment strategies which are common to all series are described under
the caption "Certain Investment Strategies."
1: Research Series
.............................................................................
> Investment Objective
The series' investment objective is long-term growth of capital and future
income. The series' objective may be changed without shareholder approval.
> Principal Investment Policies
The series invests, under normal market conditions, at least 80% of its total
assets in common stocks and related securities, such as preferred stocks,
convertible securities and depositary receipts. The series focuses on
companies that MFS believes have favorable prospects for long-term growth,
attractive valuations based on current and expected earnings or cash flow,
dominant or growing market share, and superior management. The series may
invest in companies of any size. The series' investments may include
securities traded on securities exchanges or in the over-the-counter markets.
A committee of investment research analysts selects portfolio securities
for the series. This committee includes investment analysts employed not
only by MFS, but also by MFS International (U.K.) Limited, a wholly owned
subsidiary of MFS. The committee allocates the series' assets among various
industries. Individual analysts then select what they view as the
securities best suited to achieve the series' investment objective within
their assigned industry responsibility.
The series may invest in foreign equity securities through which it may have
exposure to foreign currencies.
> Principal Risks
The principal risks of investing in the series and the circumstances
reasonably likely to cause the value of your investment in the series to
decline are described below. As with any non-money market mutual fund, the
share price of the series will change daily based on market conditions and
other factors. Please note that there are many circumstances which could
cause the value of your investment in the series to decline, and which could
prevent the series from achieving its objective, that are not described here.
The principal risks of investing in the series are:
o Market Risk: This is the risk that the price of a security held by the
series will fall due to changing economic, political or market conditions
or disappointing earnings results.
o Company Risk: Prices of securities react to the economic condition of the
company that issued the security. The series' equity investments in an
issuer may rise and fall based on the issuer's actual and anticipated
earnings, changes in management and the potential for takeovers and
acquisitions.
o Over-the-Counter Risk: Over-the-counter (OTC) transactions involve risks in
addition to those incurred by transactions in securities traded on
exchanges. OTC listed companies may have limited product lines, markets or
financial resources. Many OTC stocks trade less frequently and in smaller
volume than exchange-listed stocks. The values of these stocks may be more
volatile than exchange-listed stocks, and the series may experience
difficulty in purchasing or selling these securities at a fair price.
o Foreign Markets Risk: Investing in foreign securities involves risks
relating to political, social and economic developments abroad, as well as
risks resulting from the differences between the regulations to which U.S.
and foreign issuers and markets are subject:
> These risks may include the seizure by the government of company
assets, excessive taxation, withholding taxes on dividends and
interest, limitations on the use or transfer of portfolio assets, and
political or social instability.
> Enforcing legal rights may be difficult, costly and slow in foreign
countries, and there may be special problems enforcing claims against
foreign governments.
> Foreign companies may not be subject to accounting standards or
governmental supervision comparable to U.S. companies, and there may be
less public information about their operations.
> Foreign markets may be less liquid and more volatile than U.S. markets.
> Foreign securities often trade in currencies other than the U.S.
dollar, and the series may directly hold foreign currencies and
purchase and sell foreign currencies through forward exchange
contracts. Changes in currency exchange rates will affect the series'
net asset
3
<PAGE>
value, the value of dividends and interest earned, and gains and losses
realized on the sale of securities. An increase in the strength of the
U.S. dollar relative to these other currencies may cause the value of
the series to decline. Certain foreign currencies may be particularly
volatile, and foreign governments may intervene in the currency
markets, causing a decline in value or liquidity in the series' foreign
currency holdings. By entering into forward foreign currency exchange
contracts, the series may be required to forego the benefits of
advantageous changes in exchange rates and, in the case of forward
contracts entered into for the purpose of increasing return, the series
may sustain losses which will reduce its gross income. Forward foreign
currency exchange contracts involve the risk that the party with which
the series enters the contract may fail to perform its obligations to
the series.
o As with any mutual fund, you could lose money on your investment in the
series.
An investment in the series is not a bank deposit and is not insured or
guaranteed by the Federal Deposit Insurance Corporation or any other
government agency.
> Bar Chart and Performance Table
The bar chart and performance table below are intended to indicate some of
the risks of investing in the series by showing changes in the series'
performance over time. The performance table also shows how the series'
performance over time compares with that of one or more broad measures of
market performance. The chart and table provide past performance information.
The series' past performance does not necessarily indicate how the series
will perform in the future. The returns shown do not reflect fees and charges
imposed under the variable annuity and life insurance contracts through which
an investment may be made. If these fees and charges were included, they
would reduce these returns.
Bar Chart
The bar chart shows changes in the annual total returns of the series'
shares for each calendar year since they were first offered, assuming the
reinvestment of distributions.
[Begin Bar Chart]
22.33% 20.26% 23.39%
1996 1997 1998
[End Bar Chart]
During the period shown in the bar chart, the highest quarterly return was
21.65% (for the calendar quarter ended December 31, 1998) and the lowest
quarterly return was (14.66)% (for the calendar quarter ended September 30,
1998).
Performance Table
This table shows how the average annual total returns of the series' shares
compares to a broad measure of market performance and assumes the
reinvestment of distributions.
Average Annual Total Returns as of December 31, 1998
.............................................................................
<TABLE>
<CAPTION>
1 Year Life
<S> <C> <C>
Research Series* +23.39% +22.52%
Standard & Poor's 500 Composite Index**+ +28.58% +28.16%
</TABLE>
---------
* "Life" refers to the period from the commencement of the series'
investment operations, July 26, 1995, through December 31, 1998.
** Source: CDA/Wiesenberger. "Life" refers to the period from August 1, 1995,
through December 31, 1998.
+ The Standard & Poor's 500 Composite Index is a broad based, unmanaged
index of common stock total return performance.
> Portfolio Manager
The series is currently managed by a committee comprised of various equity
research analysts employed by the Adviser. The committee has managed the
series since its inception.
4
<PAGE>
2: New Discovery Series
.............................................................................
> Investment Objective
The series' investment objective is capital appreciation. The series'
objective may be changed without shareholder approval.
> Principal Investment Policies
The series invests, under normal market conditions, at least 65% of its total
assets in equity securities of emerging growth companies. Equity securities
include common stocks and related securities, such as preferred stocks,
convertible securities and depositary receipts for those securities. Emerging
growth companies are companies which MFS believes offer superior prospects
for growth and are either:
o early in their life cycle but which have the potential to become major
enterprises, or
o major enterprises whose rates of earnings growth are expected to accelerate
because of special factors, such as rejuvenated management, new products,
changes in consumer demand, or basic changes in the economic environment.
While emerging growth companies may be of any size, the series will
generally focus on smaller cap emerging growth companies that are early in
their life cycle. MFS would expect these companies to have products,
technologies, management, markets and opportunities which will facilitate
earnings growth over time that is well above the growth rate of the overall
economy and the rate of inflation. The series' investments in emerging
growth companies may include securities listed on a securities exchange or
traded in the over-the-counter markets.
MFS uses a bottom-up, as opposed to a top-down, investment style in
managing the equity-oriented funds (such as the series) it advises. This
means that securities are selected based upon fundamental analysis
performed by the series' portfolio manager and MFS' large group of equity
research analysts.
> Principal Risks
The principal risks of investing in the series and the circumstances
reasonably likely to cause the value of your investment in the series to
decline are described below. As with any non-money market mutual fund, the
share price of the series will change daily based on market conditions and
other factors. Please note that there are many circumstances which could
cause the value of your investment in the series to decline, and which could
prevent the series from achieving its objective, that are not described here.
The principal risks of investing in the series are:
o Market Risk: This is the risk that the price of a security held by the
series will fall due to changing economic, political or market conditions
or disappointing earnings results.
o Company Risk: Prices of securities react to the economic condition of the
company that issued the security. The series' equity investments in an
issuer may rise and fall based on the issuer's actual and anticipated
earnings, changes in management and the potential for takeovers and
acquisitions.
o Emerging Growth Companies Risk: Investments in emerging growth companies
may be subject to more abrupt or erratic market movements and may involve
greater risks than investments in other companies. Emerging growth
companies often:
> have limited product lines, markets and financial resources
> are dependent on management by one or a few key individuals
> have shares which suffer steeper than average price declines after
disappointing earnings reports and are more difficult to sell at
satisfactory prices
o Small Cap Companies Risk: Investments in small cap companies tend to
involve more risk and be more volatile than investments in larger
companies. Small cap companies may be more susceptible to market declines
because of their limited product lines, financial and management resources,
markets and distribution channels. Their shares may be more difficult to
sell at satisfactory prices during market declines.
o Over-the-Counter Risk: Over-the-counter (OTC) transactions involve risks in
addition to those associated with transactions in securities traded on
exchanges. OTC listed companies may have limited product lines, markets or
financial resources. Many OTC stocks trade less frequently and in smaller
volume than exchange listed stocks. The values of these stocks may be more
volatile than exchange listed stocks, and the series may experience
difficulty in purchasing or selling these securities at a fair price.
o As with any mutual fund, you could lose money on your investment in the
series.
5
<PAGE>
An investment in the series is not a bank deposit and is not insured or
guaranteed by the Federal Deposit Insurance Corporation or any other
government agency.
> Bar Chart and Performance Table
The bar chart and performance table are not included because the series did
not have a full calendar year of operations on December 31, 1998.
> Portfolio Manager
Brian E. Stack, a Senior Vice President of the Adviser, has been employed by
the Adviser as a portfolio manager since 1993. Mr. Stack has been the series'
portfolio manager since its inception.
6
<PAGE>
3: Growth Series
.............................................................................
> Investment Objective
The series' investment objective is to provide long-term growth of capital
and future income rather than current income. The series' objective may be
changed without shareholder approval.
> Principal Investment Policies
The series invests, under normal market conditions, at least 80% of its total
assets in common stocks and related securities, such as preferred stocks,
convertible securities and depositary receipts for those securities, of
companies which MFS believes offer better than average prospects for
long-term growth.
MFS uses a bottom-up, as opposed to a top-down, investment style in
managing the equity-oriented funds (such as the series) it advises. This
means that securities are selected based upon fundamental analysis
performed by the series' portfolio manager and MFS' large group of equity
research analysts.
In managing the series, MFS seeks to purchase securities of companies which
MFS considers well-run and poised for growth. MFS looks particularly for
companies which demonstrate:
o a strong franchise, strong cash flows and a recurring revenue stream
o a strong industry position, where there is
> potential for high profit margins
> substantial barriers to new entry in the industry
o a strong management with a clearly defined strategy
o new products or services
The series may invest in foreign securities through which it may have
exposure to foreign currencies.
> Principal Risks
The principal risks of investing in the series and the circumstances
reasonably likely to cause the value of your investment in the series to
decline are described below. As with any non-money market mutual fund, the
share price of the series will change daily based on market conditions and
other factors. Please note that there are many circumstances which could
cause the value of your investment in the series to decline, and which could
prevent the series from achieving its objective, that are not described here.
The principal risks of investing in the series are:
o Market Risk: This is the risk that the price of a security held by the
series will fall due to changing economic, political or market conditions
or disappointing earnings results.
o Growth Companies Risk: Prices of growth company securities held by the
series may fall to a greater extent than the overall equity markets (e.g.,
as represented by the Standard and Poor's Composite 500 Index) due to
changing economic, political or market conditions or disappointing growth
company earnings results.
o Foreign Securities Risk: Investments in foreign securities involve risks
relating to political, social and economic developments abroad, as well as
risks resulting from the differences between the regulations to which U.S.
and foreign issuers and markets are subject:
> These risks may include the seizure by the government of company
assets, excessive taxation, withholding taxes on dividends and
interest, limitations on the use or transfer of portfolio assets, and
political or social instability.
> Enforcing legal rights may be difficult, costly and slow in foreign
countries, and there may be special problems enforcing claims against
foreign governments.
> Foreign companies may not be subject to accounting standards or
governmental supervision comparable to U.S. companies, and there may be
less public information about their operations.
> Foreign markets may be less liquid and more volatile than U.S. markets.
7
<PAGE>
> Foreign securities often trade in currencies other than the U.S.
dollar, and the series may directly hold foreign currencies and
purchase and sell foreign currencies through forward exchange
contracts. Changes in currency exchange rates will affect the series'
net asset value, the value of dividends and interest earned, and gains
and losses realized on the sale of securities. An increase in the
strength of the U.S. dollar relative to these other currencies may
cause the value of the series to decline. Certain foreign currencies
may be particularly volatile, and foreign governments may intervene in
the currency markets, causing a decline in value or liquidity in the
series' foreign currency holdings. By entering into forward foreign
currency exchange contracts, the series may be required to forego the
benefits of advantageous changes in exchange rates and, in the case of
forward contracts entered into for the purpose of increasing return,
the series may sustain losses which will reduce its gross income.
Forward foreign currency exchange contracts involve the risk that the
party with which the series enters the contract may fail to perform its
obligations to the series.
o As with any mutual fund, you could lose money on your investment in the
series.
An investment in the series is not a bank deposit and is not insured or
guaranteed by the Federal Deposit Insurance Corporation or any other
government agency.
> Bar Chart and Performance Table
The bar chart and performance table are not included because the series had
not commenced investment operations as of December 31, 1998.
> Portfolio Manager
Stephen Pesek, a Vice President of the Adviser, has been employed as a
portfolio manager by the Adviser since 1994. Mr. Pesek has been the series
portfolio manager since its inception.
8
<PAGE>
- ----------------------------------------------
III CERTAIN INVESTMENT STRATEGIES AND RISKS
- ----------------------------------------------
Each series may depart from its principal investment strategies by
temporarily investing for defensive purposes when adverse market, economic
or political conditions exist. While a series invests defensively, it may
not be able to pursue its investment objective. A series defensive
investment policy may not be effective in protecting its value.
Each series may engage in active and frequent trading to achieve its
principal investment strategies. This may result in the realization and
distribution to shareholders of higher capital gains. Frequent trading also
increases transaction costs, which could detract from the series'
performance.
Each series may invest in various types of securities and engage in various
investment techniques and practices which are not the principal focus of
the series and therefore are not described in this Prospectus. The types of
securities and investment techniques and practices in which a series may
engage, including the principal investment techniques and practices
described above, are identified in Appendix A to this Prospectus, and are
discussed, together with their risks, in the trust's Statement of
Additional Information (referred to as the SAI), which you may obtain by
contacting MFS Service Center, Inc. (see back cover for address and phone
number).
- -------------------------------
IV MANAGEMENT OF THE SERIES
- -------------------------------
> Investment Adviser
Massachusetts Financial Services Company (referred to as MFS or the adviser)
is the investment adviser to each series. MFS is America's oldest mutual fund
organization. MFS and its predecessor organizations have a history of money
management dating from 1924 and the founding of the first mutual fund,
Massachusetts Investors Trust. Net assets under the management of the MFS
organization were approximately $102.9 billion on behalf of approximately 3.8
million investor accounts as of January 31, 1999. As of such date, the MFS
organization managed approximately $73.6 billion of net assets in equity fund
and equity portfolios. Approximately $4.7 billion of the assets managed by
MFS are invested in securities of foreign issuers and foreign denominated
securities of U.S. issuers. MFS is located at 500 Boylston Street, Boston,
Massachusetts 02116.
MFS provides investment management and related administrative services and
facilities to each series, including portfolio management and trade
execution. For these services, each series pays MFS an annual management
fee as set forth in the Expense Summary.
MFS or its affiliates generally pay an administrative service fee to
insurance companies which use the series as underlying investment vehicles
for their variable annuity and variable life insurance contracts based upon
the aggregate net assets of the series attributable to these contracts.
These fees are not paid by the series, their shareholders, or by the
contract holders.
> Administrator
MFS provides each series with certain financial, legal, compliance,
shareholder communications and other administrative services. MFS is
reimbursed by each series for a portion of the costs it incurs in providing
these services.
> Distributor
MFS Fund Distributors, Inc. (referred to as MFD), a wholly owned subsidiary
of MFS, is the distributor of shares of the series.
> Shareholder Servicing Agent
MFS Service Center, Inc. (referred to as MFSC), a wholly owned subsidiary of
MFS, performs transfer agency and certain other services for each series, for
which it receives compensation from each series.
- ----------------------------
V DESCRIPTION OF SHARES
- ----------------------------
The trust offers shares of each of its series to separate accounts
established by insurance companies in order to serve as investment vehicles
for variable annuity and variable life insurance contracts. The trust also
offers shares of each of its series to qualified pension and retirement
plans. All purchases, redemptions and exchanges of shares are made through
these insurance company separate accounts and plans, which are the record
owner of the shares. Contract holders and plan beneficiaries seeking to
purchase, redeem or exchange interests in the trust's shares should consult
with the insurance company which issued their contracts or their plan
sponsor.
9
<PAGE>
- -------------------------
VI OTHER INFORMATION
- -------------------------
> Pricing of Series' Shares
The price of each series' shares is based on its net asset value. The net
asset value of each series' shares is determined at the close of regular
trading each day that the New York Stock Exchange is open for trading
(generally, 4:00 p.m., Eastern time) (referred to as the valuation time). To
determine net asset value, each series values its assets at current market
values, or at fair value as determined by the Adviser under the direction of
the Board of Trustees that oversees the series if current market values are
unavailable. Fair value pricing may be used by a series when current market
values are unavailable or when an event occurs after the close of the
exchange on which the series' portfolio securities are principally traded
that is likely to have changed the value of the securities. The use of fair
value pricing by a series may cause the net asset value of its shares to
differ significantly from the net asset value that would be calculated using
current market values. The Money Market Series values its assets using the
amortized cost method.
Insurance companies and plan sponsors are the designees of the trust for
receipt of purchase, exchange and redemption orders from contractholders
and plan beneficiaries. An order submitted to the trust's designee by the
valuation time will receive the net asset value next calculated; provided
that the trust receives notice of the order generally by 9:30 a.m. eastern
time on the next day on which the New York Stock Exchange is open for
trading.
Certain series invest in securities which are primarily listed on foreign
exchanges that trade on weekends and other days when the series does not
price its shares. Therefore, the value of these series' shares may change
on days when you will not be able to purchase or redeem their shares.
> Distributions
Each series intends to pay substantially all of its net income (including net
short-term capital gain) to shareholders as dividends at least annually. Any
realized net capital gains are also distributed at least annually.
> Tax Considerations
Each series of the trust is treated as a separate entity for federal income
tax purposes. As long as a series qualifies for treatment as a - regulated
investment company (which it has in the past and intends to do so in the
future), it pays no federal income tax on the earnings it distributes to
shareholders. In addition, each series also intends to continue to diversify
its assets to satisfy the federal diversification tax rules applicable to
separate accounts that fund variable insurance and annuity contracts.
Shares of the series are offered to insurance company separate accounts and
qualified pension and retirement plan sponsors. Consult with the insurance
company which issued your contract or your plan sponsor or financial
advisor to understand the federal tax treatment of your investment.
> Right to Reject Purchase and Exchange Orders
Purchases and exchanges should be made for investment purposes only. Each
series reserves the right to reject or restrict any specific purchase - or
exchange request. Because an exchange request involves both a request to
redeem shares of one series and to purchase shares of another series, the
series consider the underlying redemption and purchase requests conditioned
upon the acceptance of each of these underlying requests. Therefore, in the
event that the series reject an exchange request, neither the redemption nor
the purchase side of the exchange will be processed.
> Market Timing Policies
The series are not designed for professional market timing organizations or
other entities using programmed or frequent exchanges. The - series define a
"market timer" as an individual, or organization acting on behalf of one or
more individuals, if the individual or organization makes during the calendar
year six or more exchange requests among the series.
Accounts under common ownership or control, including accounts administered
by market timers, will be aggregated for purposes of this definition.
The series may impose specific limitations on market timers, including:
o delaying for up to seven days the purchase side of an exchange request by
market timers;
10
<PAGE>
o rejecting or otherwise restricting purchase or exchange requests by market
timers; and
o permitting exchanges by market timers only into certain series.
> In-kind distributions
The series have reserved the right to pay redemption proceeds by a
distribution in-kind of portfolio securities (rather than cash). In the event
that the series makes an in-kind distribution, you could incur the brokerage
and transaction charges when converting the securities to cash. The series do
not expect to make in-kind distributions.
> Unique Nature of Series
MFS may serve as the investment adviser to other funds which have similar
investment goals and principal investment policies and risks to the series,
and which may be managed by the series' portfolio manager(s). While a series
may have many similarities to these other funds, its investment performance
will differ from their investment performance. This is due to a number of
differences between a series and these similar products, including
differences in sales charges, expense ratios and cash flows.
> Year 2000 Readiness Disclosure
The series could be adversely affected if the computer systems used by MFS,
the series' other service providers or the companies in which the series
invests do not properly process date-related information from and after
January 1, 2000 (the "Year 2000 Issue"). MFS recognizes the importance of the
Year 2000 Issue and, to address Year 2000 compliance, created a separately
funded Year 2000 Program Management Office in 1996 comprised of a specialized
staff reporting directly to MFS senior management. The Office, with the help
of external consultants, is responsible for overall coordination, strategy
formulation, communications and issue resolution with respect to Year 2000
issues. While MFS systems will be tested for Year 2000 readiness before the
turn of the century, there are significant systems interdependencies in the
domestic and foreign markets for securities, the business environments in
which companies held by the series operate and in MFS' own business
environment. MFS has been working with the series' other service providers to
identify and respond to potential problems with respect to Year 2000
readiness and to develop contingency plans. Year 2000 readiness is also one
of the factors considered by MFS in its ongoing assessment of companies in
which the series invests. There can be no assurance, however, that these
steps will be sufficient to avoid any adverse impact on the series.
> Potential Conflicts
Shares of the series are offered to the separate accounts of insurance
companies that may be affiliated or unaffiliated with MFS and each - other
("shared funding") and may serve as the underlying investments for both
variable annuity and variable life insurance contracts ("mixed funding"). Due
to differences in tax treatment or other considerations, the interests of
various contract owners might at some time be in conflict. The trust
currently does not foresee any such conflict. Nevertheless, the board of
trustees which oversees the series intends to monitor events in order to
identify any material irreconcilable conflicts which may possibly arise and
to determine what action, if any, should be taken in response. If such a
conflict were to occur, one or more separate accounts of the insurance
companies might be required to withdraw its investments in one or more
series. This might force a series to sell securities at disadvantageous
prices.
- -----------------------------
VII FINANCIAL HIGHLIGHTS
- -----------------------------
The financial highlights table is intended to help you understand the
series' financial performance for the past 5 years, or, if a series has not
been in operation that long, since the time it commenced investment
operations. Certain information reflects financial results for a single
series' share. The total returns in the table represent the rate by which
an investor would have earned (or lost) on an investment in a series
(assuming reinvestment of all distributions). This information has been
audited by the trust's independent auditors, whose report, together with
the trust's financial statements, are included in the trust's Annual Report
to shareholders. The series' Annual Report is available upon request by
contacting MFSC (see back cover for address and telephone number). These
financial statements are incorporated by reference into the SAI. The
trust's independent auditors are Deloitte & Touche LLP.
11
<PAGE>
1. Research Series
.............................................................................
<TABLE>
<CAPTION>
Period Ended
Year Ended December 31, December 31,
1998 1997 1996 1995*
---------------------------------------------------------------------------------------------------------------
<S> <C> <C> <C> <C>
Per share data (for a share outstanding throughout
each period):
Net asset value -- beginning of period ................... $ 15.80 $ 13.13 $ 10.89 $10.00
-------- -------- ------- ------
Income from investment operations# --
Net investment income[sec] .............................. $ 0.06 $ 0.05 $ 0.06 $ 0.05
Net realized and unrealized gain on investments and
foreign currency ....................................... 3.59 2.62 2.37 1.01
-------- -------- ------- ------
Total from investment operations ...................... $ 3.65 $ 2.67 $ 2.43 $ 1.06
-------- -------- ------- -------
Less distributions declared to shareholders --
From net investment income .............................. $ (0.03) $ -- $ (0.02) $(0.03)
From net realized gain on investments and foreign
currency transactions .................................. ( 0.37) -- (0.16) 0.14)
In excess of net realized gain on investments and
foreign currency transactions .......................... -- -- (0.01) --
-------- -------- ------- ------
Total distributions declared to shareholders .......... $ (0.40) $ -- $ (0.19) $(0.17)
-------- -------- ------- ------
Net asset value -- end of period ......................... $ 19.05 $ 15.80 $ 13.13 $10.89
-------- -------- ------- ------
Total return ............................................. 23.39% 20.26% 22.33% 10.62%++
Ratios (to average net assets)/Supplemental data[sec]:
Expenses## .............................................. 0.86% 0.92% 1.01% 1.02%+
Net investment income ................................... 0.33% 0.34% 0.47% 1.15%+
Portfolio turnover ....................................... 83% 99% 56% 28%
Net assets at end of period (000 omitted) ................ $567,778 $285,845 $35,710 $2,530
</TABLE>
-----------
* For the period from the commencement of the series' investment
operations, July 26, 1995, through December 31, 1995.
+ Annualized.
++ Not annualized.
# Per share data are based on average shares outstanding.
## The series has an expense offset arrangement which reduces the series'
custodian fee based upon the amount of cash maintained by the series
with its custodian and dividend disbursing agent. The series' expenses
are calculated without reduction for this expense offset arrangement.
[sec] Prior to January 1, 1998, subject to reimbursement by the series, the
investment adviser agreed to maintain expenses of the series, exclusive
of management fees, at not more than 0.25% of average daily net assets.
To the extent actual expenses were over or under this limitation, the
net investment income (loss) per share and the ratios would have been:
<TABLE>
<CAPTION>
<S> <C> <C> <C> <C>
Net investment income (loss) ........................ -- $0.06 $ -- $(0.08)
Ratios (to average net assets):
Expenses## ........................................ -- 0.88% 1.48% 3.90%+
Net investment income (loss) ...................... -- 0.38% -- (1.73)%+
</TABLE>
12
<PAGE>
2. New Discovery Series
.............................................................................
<TABLE>
<CAPTION>
Period Ended
December 31,
1998*
--------------------------------------------------------------------------------------
<S> <C>
Per share data (for a share outstanding throughout the period):
Net asset value -- beginning of period ............................... $10.00
------
Income from investment operations# --
Net investment loss[sec] ........................................... $(0.04)
Net realized and unrealized gain on investments and foreign currency 0.26
------
Total from investment operations ............................... $ 0.22
------
Net asset value -- end of period ..................................... $10.22
------
Total return ......................................................... 2.20%++
Ratios (to average net assets)/Supplemental data[sec]:
Expenses## ......................................................... 1.17%+
Net investment loss ................................................ (0.74)%+
Portfolio turnover ................................................... 130%
Net assets at end of period (000 omitted) ............................ $1,138
</TABLE>
---------
* For the period from the commencement of the series' investment
operations, May 1, 1998, through December 31, 1998.
+ Annualized.
++ Not annualized.
# Per share data are based on average shares outstanding.
## The series has an expense offset arrangement which reduces the series'
custodian fee based upon the amount of cash maintained by the series
with its custodian and dividend disbursing agent. The series' expenses
are calculated without reduction for this expense offset arrangement.
[sec] Subject to reimbursement by the series, the investment adviser agreed
to maintain the expenses of the series, exclusive of management fees,
at not more than 0.25% of average daily net assets. To the extent
actual expenses were over this limitation, the net investment loss per
share and ratios would have been:
<TABLE>
<S> <C>
Net investment loss ................................................. $(0.28)
Ratios (to average net assets):
Expenses## ......................................................... 5.22%+
Net investment loss ................................................ (4.79)%+
</TABLE>
13
<PAGE>
- ---------------------- --------------------------------
A p p e n d i x A R e s e a r c h S e r i e s
- ---------------------- --------------------------------
> Investment Techniques and Practices
In pursuing its investment objective and investment policies, the Research
Series may engage in the following investment techniques and practices, which
are described, together with their risks, in the SAI. Investment techniques
and practices which are the principal focus of the series are also described
in the Risk Return Summary of the Prospectus.
Symbols X permitted -- not permitted
- --------------------------------------------------------------------------------
<TABLE>
<CAPTION>
- -------------------------------------------------------------------
<S> <C>
Debt Securities
Asset-Backed Securities
Collateralized Mortgage Obligations and Multiclass --
Pass-Through Securities
Corporate Asset-Backed Securities --
Mortgage Pass-Through Securities --
Stripped Mortgage-Backed Securities --
Corporate Securities X
Loans and Other Direct Indebtedness --
Lower Rated Bonds X
Municipal Bonds --
Speculative Bonds X
U.S. Government Securities X
Variable and Floating Rate Obligations X
Zero Coupon Bonds, Deferred Interest Bonds and PIK --
Bonds
Equity Securities X
Foreign Securities Exposure
Brady Bonds --
Depositary Receipts X
Dollar-Denominated Foreign Debt Securities X
Emerging Markets X
Foreign Securities X
Forward Contracts X
Futures Contracts --
Indexed Securities/Structured Products X
Inverse Floating Rate Obligations --
- -------------------------------------------------------------------
</TABLE>
<TABLE>
<CAPTION>
- -------------------------------------------------------------------
<S> <C>
Investment in Other Investment Companies
Open-End Funds X
Closed-End Funds X
Lending of Portfolio Securities X
Leveraging Transactions
Bank Borrowings --*
Mortgage "Dollar-Roll" Transactions --*
Reverse Repurchase Agreements --*
Options
Options on Foreign Currencies --
Options on Futures Contracts --
Options on Securities --
Options on Stock Indices --
Reset Options --
"Yield Curve" Options --
Repurchase Agreements X
Restricted Securities X
Short Sales --
Short Sales Against the Box --
Short Term Instruments X
Swaps and Related Derivative Instruments --
Temporary Borrowings X
Temporary Defensive Positions X
Warrants X
"When-Issued" Securities --
- -------------------------------------------------------------------
</TABLE>
*May be changed only with shareholder approval.
A-1
<PAGE>
- -------------------- ---------------------------------------
A p p e n d i x A N e w D i s c o v e r y S e r i e s
- -------------------- ---------------------------------------
> Investment Techniques and Practices
In pursuing its investment objective and investment policies, the New
Discovery Series engage in the following investment techniques and practices,
X which are described, together with their risks, in the SAI. Investment
techniques and practices which are the principal focus of the series are also
described in the Risk Return Summary of the Prospectus.
Symbols X permitted -- not permitted
- --------------------------------------------------------------------------------
<TABLE>
<CAPTION>
- -------------------------------------------------------------------
<S> <C>
Debt Securities
Asset-Backed Securities
Collateralized Mortgage Obligations and Multiclass --
Pass-Through Securities
Corporate Asset-Backed Securities --
Mortgage Pass-Through Securities --
Stripped Mortgage-Backed Securities --
Corporate Securities X
Loans and Other Direct Indebtedness --
Lower Rated Bonds X
Municipal Bonds --
Speculative Bonds X
U.S. Government Securities X
Variable and Floating Rate Obligations X
Zero Coupon Bonds, Deferred Interest Bonds and PIK X
Bonds
Equity Securities X
Foreign Securities Exposure
Brady Bonds --
Depositary Receipts X
Dollar-Denominated Foreign Debt Securities X
Emerging Markets X
Foreign Securities X
Forward Contracts X
Futures Contracts X
Indexed Securities/Structured Products X
Inverse Floating Rate Obligations --
- -------------------------------------------------------------------
</TABLE>
<TABLE>
<CAPTION>
- -------------------------------------------------------------------
<S> <C>
Investment in Other Investment Companies
Open-End X
Closed-End X
Lending of Portfolio Securities X
Leveraging Transactions
Bank Borrowings *
Mortgage "Dollar-Roll" Transactions --*
Reverse Repurchase Agreements --*
Options
Options on Foreign Currencies X
Options on Futures Contracts X
Options on Securities X
Options on Stock Indices X
Reset Options X
"Yield Curve" Options X
Repurchase Agreements X
Restricted Securities X
Short Sales X
Short Sales Against the Box X
Short Term Instruments X
Swaps and Related Derivative Instruments X
Temporary Borrowings X
Temporary Defensive Positions X
Warrants X
"When-Issued" Securities X
- -------------------------------------------------------------------
</TABLE>
*May be changed only with shareholder approval.
A-2
<PAGE>
- ---------------------- ----------------------------
A p p e n d i x A G r o w t h S e r i e s
- ---------------------- ----------------------------
> Investment Techniques and Practices
In pursuing its investment objective and investment policies, the Growth
Series may engage in the following investment techniques and practices, X
which are described, together with their risks, in the SAI. Investment
techniques and practices which are the principal focus of the series are also
described in the Risk Return Summary of the Prospectus.
Symbols X permitted -- not permitted
- --------------------------------------------------------------------------------
<TABLE>
<CAPTION>
- -------------------------------------------------------------------
<S> <C>
Debt Securities
Asset-Backed Securities
Collateralized Mortgage Obligations and Multiclass --
Pass-Through Securities
Corporate Asset-Backed Securities --
Mortgage Pass-Through Securities --
Stripped Mortgage-Backed Securities --
Corporate Securities --
Loans and Other Direct Indebtedness
Lower Rated Bonds --
Municipal Bonds --
Speculative Bonds --
U.S. Government Securities --
Variable and Floating Rate Obligations X
Zero Coupon Bonds, Deferred Interest Bonds and PIK --
Bonds
Equity Securities X
Foreign Securities Exposure
Brady Bonds --
Depositary Receipts X
Dollar-Denominated Foreign Debt Securities --
Emerging Markets X
Foreign Securities X
Forward Contracts X
Futures Contracts X
Indexed Securities/Structured Products --
Inverse Floating Rate Obligations --
- -------------------------------------------------------------------
</TABLE>
<TABLE>
<CAPTION>
- --------------------------------------------------------------------
<S> <C>
Investment in Other Investment Companies
Open-End Funds X
Closed-End Funds X
Lending of Portfolio Securities X
Leveraging Transactions
Bank Borrowings --*
Mortgage "Dollar-Roll" Transactions --*
Reverse Repurchase Agreements --*
Options
Options on Foreign Currencies X
Options on Futures Contracts X
Options on Securities X
Options on Stock Indices X
Reset Options --
"Yield Curve" Options --
Repurchase Agreements X
Restricted Securities X
Short Sales --
Short Sales Against the Box --
Short Term Instruments X
Swaps and Related Derivative Instruments --
Temporary Borrowing X
Temporary Defensive Positions X
Warrants --
"When-Issued" Securities X
- -------------------------------------------------------------------
</TABLE>
*May be changed only with shareholder approval.
A-3
<PAGE>
MFS[RegTM] VARIABLE INSURANCE TRUST (SM)
If you want more information about the trust and its series, the following
documents are available free upon request:
Annual/Semiannual Reports. These reports contain information about the
series' actual investments. Annual reports discuss the effect of recent
market conditions and the series' investment strategy on the series'
performance during its last fiscal year.
Statement of Additional Information (SAI). The SAI, dated May 1, 1999,
provides more detailed information about the trust and its series and is
incorporated into this prospectus by reference.
You can get free copies of the annual/semiannual reports, the SAI and other
information about the trust and its series, and make inquiries about the
trust and its series, by contacting:
MFS Service Center, Inc.
2 Avenue de Lafayette
Boston, MA 02111-1738
Telephone: 1-800-343-2829, ext. 3500
Internet: http://www.mfs.com
Information about the trust and its series (including its prospectus, SAI and
shareholder reports) can be reviewed and copied at the:
Public Reference Room
Securities and Exchange Commission
Washington, D.C., 20549-6009
Information on the operation of the Public Reference Room may be obtained by
calling the Commission at 1-800-SEC-0330. Reports and other information about
the trust and its series are available on the Commission's Internet website
at http://www.sec.gov, and copies of this information may be obtained, upon
payment of a duplicating fee, by writing the Public Reference Section at the
above address.
The trust's Investment Company Act file number is 811-8326
MSG 11/98 224M 90/290/390/890
