<PAGE>
Prospectus
Dated May 3, 1999
MML Series Investment Fund
This prospectus describes the following funds.
MML Equity Index Fund seeks investment results that correspond to the price and
yield performance of publicly traded common stocks in the aggregate, as
represented by the Standard & Poor's 500 Composite Stock Price Index.1
MML Small Cap Value Equity Fund seeks long-term growth of capital and income by
investing primarily in small company stocks.
The Securities and Exchange Commission has not approved or disapproved these
securities or passed upon the adequacy of this Prospectus. Any statement to the
contrary is a crime.
- ----------
1 "Standard & Poor's," "Standard & Poor's 500" and "S&P 500" are trademarks
of The McGraw-Hill Companies and have been licensed for use by the Fund.
The Fund is not sponsored, endorsed, sold or promoted by Standard & Poor's,
a division of The McGraw-Hill Companies ("S&P"), or The McGraw Hill
Companies, Inc. Standard & Poor's makes no representation regarding the
advisability of investing in the Fund.
1
<PAGE>
Table Of Contents
Summary Information ......................................................... 3
About the Funds
MML Equity Index Fund ................................................... 4
MML Small Cap Value Equity Fund ......................................... 6
Summary of Principal Risks .................................................. 7
Principal Risks by Fund ..................................................... 9
Fees and Expenses ........................................................... 10
About the Investment Adviser and Sub-Advisers
Massachusetts Mutual Life Insurance Company ............................. 11
David L. Babson and Company, Inc. ....................................... 11
Mellon Equity Associates, LLP ........................................... 11
Adviser's Prior Performance
Babson .................................................................. 12
Investing in the Funds
Buying and Redeeming Shares ............................................. 14
Determining Net Asset Value ............................................. 14
Distributions and Taxation .................................................. 15
Investment Performance ...................................................... 16
Financial Highlights ........................................................ 17
Appendix - Additional Investment Policies and Risk Considerations ........... 19
2
<PAGE>
Summary Information
The MML Series Investment Fund provides a broad range of investment choices. The
following summary identifies each Fund's investment objectives, principal
investment strategies, and principal investment risks. A "Summary of Principal
Risks" of investing in the Funds begins on page 7.
For each Fund in existence for more than one year, we have provided a bar chart
showing how the investment returns of that Fund have varied in the past ten
years, or in the years since the Fund began if it is less than ten years old.
The table following each bar chart shows how that Fund's average annual returns
for the last one, five and ten years (or, for newer Funds, for shorter periods)
compares to returns of broad-based securities market indices.
MML Small Cap Value Equity Fund recently commenced operations and consequently
cannot provide annual total return information. For this Fund, we have provided
performance information based on a composite of portfolios managed with similar
investment objectives by the investment sub-adviser, set forth in the section
called "Adviser's Prior Performance."
Past performance is not necessarily an indication of future performance. It is
possible to lose money on investments in the Funds.
3
<PAGE>
About The Funds
MML Equity Index Fund
Investment Objective
The Fund's investment objective is to provide investment results that correspond
to the price and yield performance of publicly traded common stocks in the
aggregate, as represented by Standard & Poor's 500 Composite Stock Price Index.
Principal Investment Strategies
The Fund seeks to duplicate the investment results of the Standard & Poor's 500
Composite Stock Price Index by investing primarily in the following securities:
o 500 selected common stocks that comprise the index, most of which are
listed on the New York Stock Exchange
o Standard & Poor's Depositary Receipts
o stock index futures
Under normal circumstances, at least 80% of the Fund's total assets will be
invested in these securities. The percentage of the Fund's assets invested in
each stock in the index is approximately the same as the percentage it
represents in the Index. There may be circumstances when the Fund is not
invested in every stock included in the Index.
Principal Investment Risks
Among the principal risks of investing in the Fund are:
o Market Risk,
o Credit Risk,
o Management Risk,
o Derivatives Risk,
o Foreign Investment Risk, and
o Leveraging Risk
These risks, and others that may affect your investment in the Fund, are
discussed in more detail in the Summary of Principal Risks following this
section.
Past Performance
The bar chart and table below show the Fund's annual returns and its long-term
performance. The bar chart shows you how the Fund's performance has varied from
year to year. The table compares the Fund's performance over time to a
broad-based stock market index. The Fund's returns are net of its expenses, but
do not reflect additional fees and expenses that are deducted by the variable
annuity or variable life contracts through which you invest. Keep in mind that
the Fund's past performance does not indicate how it will perform in the future.
Average Annual Total Returns*
(for the period ending December 31, 1998)
<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
One Since
Year Inception
- --------------------------------------------------------------------------------
<S> <C> <C>
MML Equity Index Fund 28.22% 31.03%
- --------------------------------------------------------------------------------
S&P 500** 28.58% 31.23%
- --------------------------------------------------------------------------------
</TABLE>
* MML Equity Index Fund commenced operations on May 1, 1997.
** The S&P 500(R) is the Standard & Poor's Composite Index of 500 Stocks, a
widely recognized, unmanaged index of common stock prices.
4
<PAGE>
MML Equity Index Fund
Annual Performance
[THE FOLLOWING TABLE WAS REPRESENTED BY A BAR CHART IN THE PRINTED MATERIAL.]
<TABLE>
<CAPTION>
Total Average
Year Annual Returns
---- --------------
<S> <C>
1998 28.22%
</TABLE>
Best Quarter: Q 12/30/98 21.2%
Worst Quarter: Q 9/30/98 -10.13%
5
<PAGE>
MML Small Cap Value Equity
Fund
Investment Objective
This Fund seeks to achieve long-term growth of capital and income by investing
primarily in a diversified portfolio of equity securities of smaller companies.
Principal Investment Strategies
The Fund invests primarily in stocks, securities convertible into stocks, and
other securities such as warrants and stock rights, whose value is based on
stock prices. The Fund generally invests in publicly traded stocks of companies
with a market capitalization, at the time of purchase, of $750 million or less.
Principal Investment Risks
Among the principal risks of investing in the Fund are:
o Market Risk,
o Small Company Risk,
o Credit Risk,
o Management Risk,
o Liquidity Risk,
o Derivatives Risk,
o Foreign Investment Risk, and
o Leveraging Risk
These risks, and others that may affect your investment in the Fund, are
discussed in more detail in the Summary of Principal Risks following this
section.
Past Performance
This Fund commenced operations on June 1, 1998, and therefore cannot provide
annual total return information. Performance information for the Fund's
sub-adviser, David L. Babson and Company, Inc., is provided in the "Adviser's
Prior Performance" section of this Prospectus.
6
<PAGE>
Summary Of Principal Risks
The value of your investment in a Fund changes with the values of the
investments in a Fund's portfolio. Many factors can affect those values. Factors
that may affect a particular Fund's portfolio as a whole are called "principal
risks." They are summarized in this section. The chart at the end of this
section displays similar information. All Funds could be subject to additional
principal risks because the types of investments made by each Fund can change
over time. Investments mentioned in this summary and described in greater detail
under "Additional Investment Policies and Risk Considerations" appear in bold
type. This section also includes more information about the Funds, their
investments and the related risks. Although the Funds strive to reach their
stated goals, they cannot offer guaranteed results. You could make money in
these Funds, but you also have the potential to lose money.
Market Risk. All the Funds are subject to market risk, which is the general
risk of unfavorable market-induced changes in the value of a security. In
the case of stocks and other equity securities, market risk is the result
of a number of factors, including general economic and market conditions,
prospects of the securities' issuer, changing interest rates, and real or
perceived economic and competitive industry conditions.
MML Small Cap Value Fund maintains substantial exposure to equities and do
not attempt to time the market. Because of this exposure, the possibility
that stock market prices in general will decline over short or even
extended periods subjects these Funds to unpredictable declines in the
value of their shares, as well as periods of poor performance. Market risk
also includes more specific risks affecting the issuer, such as management
performance, financial leverage, industry problems and reduced demand for
the issuer's goods or services.
o Smaller Company Risk. Market risk and liquidity risk are particularly
pronounced for stocks of companies with relatively small market
capitalizations. These companies may have limited product lines, markets or
financial resources or they may depend on a few key employees. MML Small
Cap Value Equity Fund generally has the greatest exposure to this risk.
o Credit Risk. All of the Funds are subject to credit risk. This is the risk
that the issuer or the guarantor of a debt security, or the counterparty to
a derivatives contract or securities loan, will be unable or unwilling to
make timely principal and/or interest payments, or to otherwise honor its
obligations. There are varying degrees of credit risk, which are often
reflected in credit ratings.
o Management Risk. Each Fund is subject to management risk because it is an
actively managed investment portfolio. Management risk is the chance that
poor security selection will cause the Fund to underperform other funds
with similar investment objectives. The Funds' investment advisers manage
the Funds according to the traditional methods of active investment
management, that is, by buying and selling of securities based upon
economic, financial and market analysis and investment judgment. The Funds'
investment advisers apply their investment techniques and risk analyses in
making investment decisions for the Funds, but there can be no guarantee
they will produce the desired result.
o Liquidity Risk. Liquidity risk exists when particular investments are
difficult to purchase or sell, possibly preventing a Fund from selling
these illiquid securities at an advantageous price. Investments in
derivatives, foreign securities, private placements and securities with
small market capitalization and substantial market and/or credit risk tend
to have greater liquidity risk.
o Derivatives Risk. All Funds may use derivatives, which are financial
contracts
7
<PAGE>
whose value depends on, or is derived from, the value of an underlying
asset, reference rate or index. The Funds will sometimes use derivatives as
part of a strategy designed to reduce other risks and sometimes will use
derivatives for leverage, which increases opportunities for gain but also
involves greater risk. In addition to other risks such as the credit risk
of the counterparty, derivatives involve the risk of mispricing or improper
valuation and the risk that changes in the value of the derivative may not
correlate perfectly with relevant assets, rates and indices. In addition, a
Fund's use of derivatives may affect the timing and amount of taxes payable
by shareholders.
o Foreign Investment Risk. Funds investing in foreign securities may
experience more rapid and extreme changes in value than Funds with
investments solely in securities of U.S. companies. This is because the
securities markets of many foreign countries are relatively small, with a
limited number of companies representing a small number of industries. In
addition, foreign securities issuers are not usually subject to the same
degree of regulation as U.S. issuers. Reporting, accounting and auditing
standards of foreign countries differ, in some cases significantly, from
U.S. standards. Also, nationalization, expropriation or confiscatory
taxation, currency blockage, political changes or diplomatic developments
could adversely affect a Fund's investments in a foreign country. In the
event of nationalization, expropriation or other confiscation, a Fund could
lose its entire investment. Adverse developments in certain regions, such
as Southeast Asia, can also adversely affect securities of other countries
whose economies appear to be unrelated.
Because the Standard & Poor's 500 Composite Stock Price Index includes the
stocks of some foreign issuers, MML Equity Index Fund may also invest in
these foreign securities, subjecting this Fund to foreign investment risk.
o Currency Risk. Currency risk is caused by uncertainty in foreign currency
exchange rates. Fluctuations in the value of the U.S. dollar relative to
foreign currencies may enhance or diminish returns a U.S. investor would
receive on foreign investments. The Funds may, but will not necessarily,
engage in foreign currency transactions in order to protect the value of
portfolio holdings denominated in particular currencies against
fluctuations in value. There is a risk that those currencies will decline
in value relative to the U.S. dollar, or, in the case of hedging positions,
that the U.S. dollar will decline in value relative to the currency hedged.
o Leveraging Risk. When a Fund borrows money or otherwise leverages its
portfolio, the value of an investment in that Fund will be more volatile
and all other risks will tend to be compounded. All of the Funds may take
on leveraging risk by investing collateral from securities loans, by using
derivatives and by borrowing money to repurchase shares or to meet
redemption requests.
8
<PAGE>
Principal Risks by Fund
The following chart summarizes the Principal Risks of each Fund. Risks not
marked for a particular Fund may, however, still apply to some extent to that
Fund at various times.
<TABLE>
<CAPTION>
Market Smaller Credit Management Liquidity Derivative Foreign Currency Leveraging
Fund Risk Company Risk Risk Risk Risk Risk Investment Risk Risk Risk
<S> <C> <C> <C> <C> <C> <C> <C> <C> <C>
MML Equity Index Fund X X X X X X
MML Small Cap Value Equity Fund X X X X X X X X X
</TABLE>
9
<PAGE>
Fees and Expenses
As an investor, you pay certain fees and expenses in connection with your
investment. These fees and expenses will vary depending on the Fund in which you
invest. The fee tables shown below are meant to assist you in understanding
these fees and expenses. Annual Fund Operating Expenses refer to the costs of
operating the Funds. These costs are deducted from a Fund's assets, which means
you pay them indirectly.
This table describes the fees and expenses you may pay if you invest in the
Funds.
<TABLE>
<CAPTION>
MML
MML Small Cap
Equity Value
Index Equity
- --------------------------------------------------------------------------------
<S> <C> <C>
Annual Fund Operating Expenses
(expenses that are deducted from
Fund assets)
% of average daily net assets 0.1992% 0.6179%
Management Fees 0.3996% 0.6715%
Other Expenses -- -0.507%*
Total 0.4965% 0.7815%
- --------------------------------------------------------------------------------
</TABLE>
* MassMutual has agreed to bear the expenses (other than the management fees,
interest, taxes, brokerage commissions and extraordinary expenses) in excess of
.11% of the average daily net asset values through April 30, 2000 for MML Small
Cap Value Equity Fund. Such agreement cannot be terminated unilaterally by
MassMutual.
EXAMPLES. These examples are intended to help you compare the cost of investing
in MML Series Investment Fund with the cost of investing in other mutual funds.
The examples assume you invest $10,000 in the shares of the Funds for the time
periods indicated, that your investment earns a 5% return each year and that
each Fund's operating expenses remain the same. Although your actual costs may
be higher or lower, based on these assumptions your costs would be:
<TABLE>
<CAPTION>
MML
MML Small Cap
Equity Value
Index Equity
- --------------------------------------------------------------------------------
<S> <C> <C>
1 Year $62.86 $82.06
3 Years $196.95 $369.00
5 Years $343.02 $677.57
10 Years $767.87 $1,552.99
- --------------------------------------------------------------------------------
</TABLE>
Since the Funds do not impose any shareholder fees, the figures shown would be
the same whether you sold your shares at the end of a period or kept them.
10
<PAGE>
About The Investment Adviser and
Sub-Advisers
MassMutual is the Funds' investment manager and is responsible for providing all
necessary investment management and administrative services. Founded in 1851,
MassMutual is a mutual life insurance company that provides a broad portfolio of
insurance, money management, retirement and asset accumulation products and
services for individuals and businesses. MassMutual, together with its
subsidiaries, has assets in excess of $67 billion and assets under management in
excess of $176 billion. MassMutual uses its subsidiary, David L. Babson and
Company, Inc., to help manage certain Funds.
In 1998, each Fund paid MassMutual an investment management fee based on a
percentage of its average daily net assets as follows: MML Equity Index Fund,
.40%; MML Small Cap Value Equity Fund, .39%.
David L. Babson and Company, Inc. ("Babson") manages the investments of MML
Small Cap Value Fund. Babson has provided investment advice to individual
and institutional investors for more than 50 years and manages more than
$19 billion.
George M. Ulrich is the person principally responsible for the day-to-day
management of MML Small Cap Value Equity Fund. He has managed the Fund
since its inception and has 32 years of investment experience. He joined
Babson in 1996 and has been associated with the MassMutual organization as
a portfolio manager since 1983.
Mellon Equity Associates, LLP ("Mellon Equity") serves as MML Equity Index
Fund's investment sub-adviser, providing day-to-day management of the
Fund's investments. Mellon Equity is a Pennsylvania business trust founded
in 1987 whose beneficial owners are Mellon Bank N.A. and MMIP, Inc. (a
wholly owned subsidiary of Mellon Bank Corporation ("Mellon Bank")). Mellon
Equity is a registered investment adviser. As of December 31, 1998, Mellon
Equity had approximately $9 billion assets under management, and serves as
the investment adviser or sub-adviser of 18 other investment companies.
11
<PAGE>
Adviser's Prior Performance
Babson
Babson serves as the investment manager of other accounts that have investment
objectives, policies and strategies that are substantially similar to those of
MML Small Cap Value Equity Fund (collectively, the "Small Cap Value Accounts").
The performance information shown below is based on a composite of the Small Cap
Value Accounts and has been adjusted to give effect to the estimated fees and
expenses (without giving effect to any expense waivers or reimbursements) of the
Fund during its first year of operation.
The performance information shown below has not been adjusted to give effect to
charges imposed by the separate investment accounts that invest in the Fund,
which, if included, would decrease the performance figures shown. The
performance of the Small Cap Value Accounts composite has been calculated in
accordance with standards established by the Association for Investment
Management and Research.
The performance represents total return, which includes capital appreciation and
income. During the entire ten year period ended December 31, 1998, George M.
Ulrich, the individual responsible for the day-to-day portfolio management of
the Fund, has been the portfolio manager of the Small Cap Value Accounts. Unlike
the Fund, the Small Cap Value Accounts include accounts that were not registered
under the 1940 Act and therefore were not subject to certain investment
restrictions imposed by the 1940 Act. In addition, the Small Cap Value Accounts
include accounts that were not subject to Subchapter M of the Internal Revenue
Code (the "Code"), which imposes certain limitations on the investment
operations of the Fund. If the Small Cap Value Accounts had all been registered
under the 1940 Act, and subject to Subchapter M of the Code, their performance
might have been adversely affected. The Fund's expenses, timing of purchases and
sales of portfolio securities, availability of cash flows, and brokerage
commissions are all additional reasons that the performance results of the Fund
may vary from that of the Small Cap Value Accounts.
The following table also shows the average annual total return of the Russell
2000 Index(R) for the same periods.
The quoted performance does not represent the historical performance of the Fund
and should not be interpreted as being indicative of the future performance of
the Fund.
Composite Performance of
Small Cap Value Accounts
<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
1 Yr. Period 3 Yr. Period 5 Yr. Period 10 Yr. Period
Ended Ended Ended Ended
12/31/98 12/31/98 12/31/98 12/31/98
- --------------------------------------------------------------------------------
<S> <C> <C> <C> <C>
Small Cap
Value
Accounts -8.93% 15.18% 11.91% 13.08%
- --------------------------------------------------------------------------------
Russell 2000
Index* -2.55% 11.58% 11.87% 12.92%
- --------------------------------------------------------------------------------
</TABLE>
* The Russell 2000 Index(R) is a widely recognized unmanaged index consisting
of 2,000 small capitalization common stocks.
12
<PAGE>
Composite Performance of Small Cap Value Accounts
[THE FOLLOWING TABLE WAS REPRESENTED BY A BAR CHART IN THE PRINTED MATERIAL.]
<TABLE>
<CAPTION>
Years Average Annual Total Returns
----- ----------------------------
<S> <C>
1989 18.61%
1990 -5.46%
1991 29.21%
1992 17.45%
1993 14.46%
1994 -4.31%
1995 20.07%
1996 22.93%
1997 36.48%
1998 -8.93%
</TABLE>
Best Quarter: Q 6/30/97 18.65%
Worst Quarter: Q 9/30/98 -19.08
Set forth below is the composite annual performance and average annual total
returns for the Small Cap Value Accounts, without considering investment
management, administrative or custody fees.
<TABLE>
<CAPTION>
1989 1990 1991 1992 1993
---- ---- ---- ---- ----
<S> <C> <C> <C> <C>
19.27% -4.91% 29.87% 17.87% 14.89%
<CAPTION>
1994 1995 1996 1997 1998
---- ---- ---- ---- ----
<S> <C> <C> <C> <C>
-3.9% 20.63% 23.67% 37.35% -8.3%
<CAPTION>
One Year Three Year Five Year Ten Year
-------- ---------- --------- --------
<S> <C> <C> <C>
-8.3% 20.63% 14.89% 19.27%
</TABLE>
13
<PAGE>
Investing In The Funds
Buying and Redeeming Shares
MML Series Investment Fund provides an investment vehicle for the separate
investment accounts of variable life and variable annuity contracts offered by
companies such as MassMutual. Shares of MML Series Investment Fund are not
offered to the general public.
The shares of each Fund are sold at their net asset value (NAV) as next computed
after receipt of the purchase order, without the deduction of any selling
commission or "sales load." The Funds' generally determine their NAV at 4:00
p.m. Eastern time every day the New York Stock Exchange is open. Your purchase
order will be priced at the next net asset value calculated after your order is
accepted by the Funds. The Funds will suspend selling their shares during any
period when the determination of NAV is suspended.
The Funds redeem their shares at their next NAV computed after the Funds'
transfer agent receives your redemption request. You will usually receive
payment for your shares within 7 days after the transfer agent receives your
written redemption request. The Funds can also suspend or postpone payment, when
permitted by applicable law and regulations.
The redemption price may be paid in cash or wholly or partly in kind if the
Funds' determine that such payment is advisable in the interest of the remaining
shareholders. In making such payment wholly or partly in kind, a Fund will, as
far as may be practicable, deliver securities or property which approximate the
diversification of its entire assets at the time. No fee is charged on
redemption.
Determining Net Asset Value
The Funds generally determine their NAV's at 4:00 p.m. Eastern time on each day
the New York Stock Exchange is open.
The Funds generally value portfolio securities based on market value. For
example, equity securities and long-term bonds are valued on the basis of
valuations provided by one or more pricing services approved by the Funds' Board
of Trustees. Short-term securities with more than 60 days to maturity from the
date of purchase are valued at fair market value. Money market securities with a
maturity of 60 days or less are generally valued at their amortized cost.
14
<PAGE>
Distributions and Taxation
Distributions
The declaration and distribution policies specific to each Fund are outlined
below.
o MML Equity Index and MML Small Cap Value Equity Funds. Distributions, if
any, are declared and paid annually. Distributions may be taken either in
cash or in additional shares of the respective Funds at net asset value on
the first business day after the record date for the distribution, at the
option of the shareholder.
Taxation
Each Fund intends to continue to qualify as a regulated investment company under
Subchapter M of the Internal Revenue Code. As a result, none of the Funds will
be subject to federal income tax on any net income or any capital gains to the
extent they are distributed or are deemed to have been distributed to
shareholders.
Generally, owners of variable life and variable annuity contracts are not taxed
currently on income or gains realized with respect to such contracts. However,
some distributions from such contracts may be taxable at ordinary income tax
rates. In addition, distributions made to an owner who is younger than 59 1/2
years may be subject to a 10% penalty tax. Investors should ask their own tax
advisors for more information on their own tax situation, including possible
foreign, state or local taxes.
In order for investors to receive the favorable tax treatment available to
holders of variable annuity and variable life contracts, the separate accounts
underlying such contracts, as well as the Funds in which these accounts invest,
must meet certain diversification requirements. Each Fund intends to comply with
these requirements. If a Fund does not meet these requirements, income from the
contracts would be taxable currently to the holders of such contracts.
A Fund's investment in foreign securities may be subject to foreign withholding
taxes. In that case, the Fund's yield on those securities would be decreased.
Please refer to the Statement of Additional Information for more information
regarding the tax treatment of the Funds. Please refer to the prospectuses of
the separate accounts with interests in the Funds for a discussion of the tax
consequences of variable annuity and variable life contracts.
15
<PAGE>
Investment Performance
From time to time, each of the Funds may advertise investment performance
figures. These figures are based on historical earnings and should not be used
to predict the future performance of a Fund.
Yields and total returns shown for the Funds are net of the Funds' operating
expenses, but do not take into account charges and expenses attributable to the
variable annuity or variable life insurance contracts through which you invest.
These expenses reduce the returns and yields you ultimately receive, so you
should bear those expenses in mind when evaluating the performance of the Funds
and when comparing the yields and returns of the Funds with those of other
mutual funds.
MML Equity Index Fund and MML Small Cap Value Equity Fund may quote yield. The
yield for each of these Funds refers to the net investment income earned by the
Fund over a 30-day period (which period will be stated in the advertisement).
This income is then assumed to be earned for a full year and to be reinvested
each month for six months. The resulting semiannual yield is doubled.
Each of the Funds may advertise its total return and its holding period return
for various periods of time. Total return is calculated by determining the
average annual compounded rate of return that an investment in the Fund earned
over a specified period, assuming reinvestment of all distributions. Holding
period return refers to the percentage change in the value of an investment in a
Fund over a period of time assuming reinvestment of all distributions. Total
return and holding period return differ from yield. The return figures include
capital changes in an investment while yield measures the rate of net income
generated by a Fund. The difference between total return and holding period
return is that total return is an average annual figure while holding period
return is an aggregate figure for the entire period.
For more information about the investment performance of the Funds, see the
Statement of Additional Information.
16
<PAGE>
Financial Highlights
The financial highlights table is intended to help you understand the Funds'
financial performance for the past 5 years. Certain information reflects
financial results for a single Fund share. The total returns in the table
represent the rate that an investor would have earned on an investment in the
Fund (assuming reinvestment of all dividends and distributions). This
information has been audited by PricewaterhouseCoopers LLP, whose report, along
with the Funds' financial statements, are included in the Annual Report, which
is available on request.
Selected per share data for each series share outstanding throughout each year
ended December 31:
MML EQUITY INDEX FUND
<TABLE>
<CAPTION>
For the Period
May 1, 1997
(Commencement of
For the year Ended Operations) through
December 31, 1998 December 31, 1997*
----------------- ------------------
<S> <C> <C>
Net asset value:
Beginning of period $12.080 $10.000
------- -------
Income from investment operations:
Net investment income 0.128 0.092
Net realized and unrealized gain on investments 3.284 2.101
------- -------
Total from investment operations 3.412 2.193
------- -------
Less distributions:
Dividends from net investment income (0.128) (0.092)
Distributions from net realized gains (0.104) (0.021)
------- -------
Total distributions (0.232) (0.113)
------- -------
Net asset value:
End of year $15.260 $12.080
======= =======
Total return*** 28.22% 21.39%**
Net assets (in millions): $36.07 $24.20
Ratio of operating expenses to average net assets:
Before expense waiver 0.60% 0.43%**
After expense waiver 0.50% --
Ratio of net investment income to average net assets:
Before expense waiver 0.91% 0.80%**
After expense waiver 1.01% --
Portfolio turnover rate 5.19% 2.00%
</TABLE>
* The Fund commenced operations on May 1, 1997.
** Percentages represent results for the period and are not annualized.
*** Total return information shown in the Financial Highlights tables does not
reflect expenses that apply at the separate account level or to related
insurance products. Inclusion of these charges would reduce the total
return figures for the period shown.
17
<PAGE>
MML SMALL CAP VALUE EQUITY FUND
<TABLE>
<S> <C>
Net asset value:
Beginning of period $10.000
-------
Income from investment operations:
Net investment income 0.029
Net realized and unrealized loss on investments (1.506)
-------
Total from investment operations (1.477)
-------
Less distributions:
Dividends from net investment income (0.030)
-------
Total distributions (0.030)
-------
Net asset value:
End of year $ 8.493
=======
Total return** (14.77%)
Net assets (in millions): $10.44
Ratio of expenses to average net assets:
Before expense waiver 0.85%*
After expense waiver 0.44%*
Ratio of net investment income to average net assets:
Before expense waiver 0.81%*
After expense waiver 0.42%*
Portfolio turnover rate 23.40%*
</TABLE>
* Percentages represent results for the period and are not annualized.
** Total return shown in the Financial Highlights tables does not reflect
expenses that apply at the separate account level or to related insurance
products. Inclusion of these charges would reduce the total return figures
for the period shown.
18
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Appendix
ADDITIONAL INVESTMENT POLICIES AND RISK CONSIDERATIONS
The Funds may invest in a wide range of investments and engage in various
investment-related transactions and practices. These practices may be changed by
the Board of Trustees without the consent of shareholders. Some of the more
significant practices and some associated risks are discussed below.
Year 2000 Issue
Like other businesses and governments around the world, the Funds could be
adversely affected if the computer systems used by the Funds' service providers
and those with which they do business do not properly recognize the year 2000.
This is commonly known as the "Year 2000 Issue." In 1996, MassMutual began an
enterprise-wide process of identifying, evaluating and implementing changes to
its computer systems to address the Year 2000 Issue. MassMutual is addressing
the Year 2000 Issue internally with modifications to existing programs and
conversions to new programs. MassMutual has advised the Funds that the Year 2000
Issue is one of MassMutual's highest business operational priorities. MassMutual
is also seeking assurances from the Funds' other service providers, including
sub-advisers to the Funds, and others with which MassMutual and the Funds
conduct business to identify and resolve Year 2000 issues. In addition, because
the Year 2000 issue affects virtually all organizations, the companies in which
the Funds invest could be adversely impacted by the Year 2000 Issue. The extent
of such impact cannot be predicted.
Derivatives Transactions
Although each Fund is authorized to engage in transactions involving
derivatives, as more fully described in the Statement of Additional Information,
the Funds' use of derivatives, other than forward contracts, is minimal.
The Funds may use derivatives to attempt to:
o protect against possible declines in the market value of a Fund's portfolio
resulting from downward trends in relevant markets (for example, in the
debt securities markets generally due to increasing interest rates);
o facilitate selling securities for investment reasons;
o protect a Fund's unrealized gains or limit unrealized losses in the value
of its securities;
o establish a position in the relevant securities markets as a temporary
substitute for purchasing or selling particular securities;
o manage the effective maturity or duration of fixed-income securities in a
Fund's portfolio; or
o manage its exposure to changing security prices (collectively, "Derivatives
Transactions").
MML Series Investment Fund has no present intent to enter into derivatives
transactions with regard to MML Small Cap Value Equity Fund. The Funds will not
use derivatives for speculative purposes.
MML Equity Index Fund may buy or sell stock index futures and other similar
instruments, as more fully discussed in the Statement of Additional Information.
MML Equity Index Fund may purchase stock index futures in anticipation of taking
a market position when, in the opinion of Mellon Equity, available cash balances
do not permit an economically efficient trade in the cash market. The Fund also
may sell stock index futures to terminate existing positions it may have as a
result of its purchases of stock index futures. Investments in stock index
futures typically require greater available cash balances than do investments in
Standard & Poor's Depositary Receipts.
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Although MML Equity Index Fund will not be a commodity pool, derivatives subject
this Fund to the rules of the Commodity Futures Trading Commission which limit
the extent to which the Fund can invest in certain derivatives. The Fund may
invest in stock index futures contracts for hedging purposes without limit.
However, MML Equity Index Fund may not invest in such contracts for other
purposes if the sum of the amount of initial margin deposits, other than for
bona fide hedging purposes, exceeds 5% of the liquidation value of the Fund's
assets, after taking into account unrealized gains and unrealized losses on such
contracts.
Standard & Poor's Depositary Receipts
MML Equity Index Fund may invest in Standard & Poor's Depositary Receipts when,
in the opinion of Mellon Equity, available cash balances would not otherwise
allow the Fund to invest such cash balances in a manner that adequately
corresponds to the Index. Investments in these depositary receipts typically
require less available cash balances than do investments in stock index futures.
These depositary receipts represent an interest in the portfolio of S&P 500
stocks held by a unit investment trust. They trade on the American Stock
Exchange and may be bought and sold like common stock at any time during the
trading day. Holders of the depositary receipts are entitled to receive
dividends that accrue to stocks held by the unit investment trust, less trust
expenses. An investment in these depositary receipts is intended to provide
investment results that generally correspond to the price and yield performance
of the Index.
Forward Contracts or "When Issued"
Securities
Each Fund may purchase or sell securities on a "when issued" or delayed delivery
or on a forward commitment basis ("forward contracts"). When such transactions
are negotiated, the price is fixed at the time of commitment, but delivery and
payment for the securities can take place a month or more after the commitment
date. The securities purchased or sold are subject to market fluctuations, and
no interest accrues to the purchaser during this period. At the time of
delivery, the securities may be worth more or less than the purchase or sale
price.
There can be no assurance that the use of forward contracts or other derivatives
by any of the Funds will assist it in achieving its investment objectives. Risks
inherent in the use of derivatives include:
o the risk that interest rates and securities prices will not move in the
direction anticipated;
o imperfect correlation between the prices of forward contracts and the
prices of the securities being hedged;
o the fact that skills needed to use these strategies are different from
those needed to select portfolio securities; and
o the fact that forward contracts involve a risk of loss if the value of the
security to be purchased declines prior to the settlement date. This is in
addition to the risk of decline of the Fund's other assets.
A Fund will not enter into a forward contract if, as a result, more than 25% of
the Fund's total assets would be in one or more segregated accounts covering
forward contracts.
Portfolio Management
The Advisers intend to use trading as a means of managing the portfolios of the
Funds in seeking to achieve their investment objectives. The Advisers, on behalf
of the Funds, will engage in trading when it believes that the trade, net of
transaction costs, will improve interest income or capital appreciation
potential, or will lessen capital loss potential.
Whether the goals discussed above will be achieved through trading depends on
the Advisers' ability to evaluate particular securities and anticipate relevant
market factors, including interest rate trends and variations from these trends.
Such trading places an added burden on the Advisers' ability to obtain relevant
information, evaluate it properly and take advantage of their evaluations by
completing transactions on a favorable basis. The Advisers' evaluations and
expectations prove to be incorrect, a Fund's income or capital appreciation
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may be reduced and its capital losses may be increased. Portfolio trading
involves transaction costs, but, as explained above, will be engaged in when the
Advisers believe the result of trading, net of transaction costs, will benefit
the Funds.
Restricted And Illiquid Securities
None of the Funds currently expect to invest in restricted or illiquid
securities. However, each Fund may invest not more than 15% of its net assets in
illiquid securities. These policies do not limit the purchase of securities
eligible for resale to qualified institutional buyers pursuant to Rule 144A
under the Securities Act of 1933, as amended, provided such securities are
determined to be liquid by Funds' Board of Trustees, or by the Advisers,
pursuant to Board-approved guidelines. If there is a lack of trading interest in
particular Rule 144A securities, a Fund's holdings of those securities may be
illiquid, resulting in the possibility of undesirable delays in selling these
securities at prices representing fair value.
Securities Lending
MML Equity Index Fund may seek additional income by making loans of portfolio
securities of not more than 33% of its total assets taken at current value.
Lending portfolio securities may involve the risk of delay in recovery of the
securities loaned or possible loss of rights in the collateral should the
borrower fail financially. Loans will be made only to borrowers deemed by the
Advisers to be of good standing.
Cash Positions
Each Fund may hold cash or cash equivalents to provide for liquidity (e.g.,
expenses and anticipated redemption payments) so that an orderly investment
program may be carried out in accordance with the Fund's investment policies. To
provide liquidity or for temporary defensive purposes, each Fund may invest any
portion of its assets in investment grade debt securities. Taking this type of
temporary defensive position may affect a Fund's ability to achieve its
investment objective.
Money Market Instruments
All Funds, including MML Equity Index Fund, may invest in money market
instruments when they have cash reserves. These investments consist of U.S.
government securities, time deposits, certificates of deposit, bankers'
acceptances, high-grade commercial paper, and repurchase agreements. The
Statement of Additional Information describes these instruments more fully.
Foreign Securities
Investments in foreign securities offer potential benefits not available from
investing solely in securities of domestic issuers. These include the
opportunity to invest in foreign issuers that appear to offer growth potential,
or to invest in foreign countries with economic policies or business cycles
different from those of the United States or foreign stock markets that do not
move in a manner parallel to U.S. markets, thereby diversifying risks of
fluctuations in portfolio value.
Investments in foreign securities entail certain risks, such as the possibility
of one or more of the following: imposition of dividend or interest withholding
or confiscatory taxes; currency blockages or transfer restrictions;
expropriation, nationalization, military coups or other adverse political or
economic developments; less government supervision and regulation of securities
exchanges, brokers and listed companies; and the difficulty of enforcing
obligations in other countries. Certain markets may require payment for
securities before delivery. A Fund's ability and decisions to purchase and sell
portfolio securities may be affected by laws or regulations relating to the
convertibility of currencies and repatriation of assets. Further, it may be more
difficult for a Fund's agents to keep currently informed about corporate actions
which may affect the prices of portfolio securities. Communications between the
United States and foreign countries may be less reliable than within the United
States, thus increasing the risk of delayed settlements of portfolio
transactions or loss of certificates for portfolio securities.
Industry Concentration
As a general rule, MML Small Cap Value Equity Fund will not acquire securities
of issuers in any one industry (as determined by the Board of Trustees) if as a
result more than 25% of the value of the total assets of the Fund would be
invested in such industry.
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Industry Diversification
MML Equity Index Fund is classified as non-diversified, which means that the
proportion of the Fund's assets that may be invested in the securities of a
single issuer is not limited by the Investment Company Act of 1940, as amended
(the "1940 Act"). A "diversified" investment company is required by the 1940 Act
generally, with respect to 75% of its total assets, to invest not more than 5%
of such assets in the securities of a single issuer. Since a relatively high
percentage of the Fund's assets may be invested in the securities of a limited
number of issuers, some of which may be within the same economic sector, the
Fund's portfolio may be more sensitive to the changes in market value of a
single issuer or industry. However, to meet Federal tax requirements, at the
close of each quarter the Fund may not have more than 25% of its total assets
invested in any one issuer and, with respect to 50% of total assets, not more
than 5% of its total assets invested in any one issuer. These limitations do not
apply to U.S. government securities.
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MML SERIES INVESTMENT FUND
1295 State Street
Springfield, Massachusetts 01111-0001
Learning More About the Funds
You can learn more about the Funds by reading the Funds' Annual and Semiannual
Reports and the Statement of Additional Information (SAI). This information is
available free upon request. In the Annual and Semiannual Reports, you will find
a discussion of market conditions and investment strategies that significantly
affected each Fund's performance during the period covered by the report and a
listing of portfolio securities. The SAI will provide you more detail regarding
the organization and operation of the Funds, including their investment
strategies. The SAI is incorporated by reference into this Prospectus and is
therefore legally considered a part of this Prospectus.
How to Obtain Information
From MML Series Investment Fund: You may request information about the Funds
(including the Annual/Semiannual Reports and the SAI) or make shareholder
inquiries by calling 1-800-767-1000, ext. 8480 or by writing MML Series
Investment Fund, c/o Massachusetts Mutual Life Insurance Company, 1295 State
Street, Springfield, Massachusetts 01111-0111, Attention Shareholder Services,
F471.
From the SEC: You may review information about the Funds (including the SAI) at
the SEC's Public Reference Room in Washington, D.C. (call 1-800-SEC-0330 for
information regarding the operation of the SEC's public reference room). You can
get copies of this information, upon payment of a copying fee, by writing to the
SEC's Public Reference Section, Washington, D.C. 20549-6009. Alternatively, if
you have access to the Internet, you may obtain information about the Funds from
the SEC's Internet site at http://www.sec.gov. When obtaining information about
the Funds from the SEC, you may find it useful to reference the Funds' SEC file
number: 811-2224.
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MML SERIES
INVESTMENT FUND
1295 State Street
Springfield, Massachusetts 01111
INVESTMENT MANAGER
Massachusetts Mutual Life Insurance Company
1295 State Street
Springfield, Massachusetts 01111
INVESTMENT SUB-ADVISERS
David L. Babson and Company, Incorporated
One Memorial Drive
Cambridge, Massachusetts 02142
Mellon Equity Associates, LLP
500 Grant Street Suite 3700
Pittsburgh, Pennsylvania 15258
INDEPENDENT ACCOUNTANTS
PricewaterhouseCoopers LLP
2300 Tower Square 1500 Main Street
Springfield, Massachusetts 01101
CUSTODIANS
Citibank, N.A.
111 Wall Street
New York, New York
Boston Safe Deposit and Trust Company
One Boston Place
Boston, Massachusetts 02108
PRINCIPAL UNDERWRITER
MML Distributors, LLC
1414 Main Street
Springfield, Massachusetts 01144
CO-UNDERWRITER
MML Investors Services, Inc.
1414 Main Street
Springfield, MA 01144
LEGAL COUNSEL
Ropes & Gray
One International Place
Boston, Massachusetts 02110
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