<PAGE>
JOHN HANCOCK VARIABLE SERIES TRUST I
SUPPLEMENT DATED AUGUST 24, 1999
TO PROSPECTUSES DATED MAY 3, 1999
The above-captioned prospectuses (the "Prospectuses") are hereby amended and
supplemented as follows:
1. THE SECTIONS ENTITLED "GOAL AND STRATEGY", "SUBADVISER" AND "MAIN RISKS" FOR
THE EMERGING MARKETS EQUITY FUND (WHICH APPEAR ON PAGES 38 AND 39 OF THE
PROSPECTUS) ARE REVISED TO READ AS FOLLOWS:
GOAL AND STRATEGY
This is an emerging markets stock fund that seeks long-term growth in capital.
The Fund invests primarily in the stocks of companies in countries having
economies or markets generally considered by the World Bank or United Nations to
be emerging or developing.
In making country allocation decisions, the manager analyzes the global
environment and selects countries with:
* Improving macroeconomic, political and social trends, and
* attractive valuation levels.
The manager selects stocks using fundamental proprietary research to identify
companies:
* Having strong earnings growth potential,
* selling below their intrinsic value, and
* having shareholder-focused management, dominant products, and well established
distribution channels.
The Fund normally invests:
* in at least 15 emerging markets countries, and
* no more than 30% of its assets in any single country.
The Fund normally invests in 100 to 250 stocks in 20 to 25 countries. The Fund
normally has 10% or less of its assets in cash and cash equivalents.
The Fund may purchase other types of securities, for example: American
Depository Receipts (ADRs), Global Depository Receipts (GDRs), European
Depository Receipts (EDRs), high quality short-term debt securities, and certain
derivatives (investments whose value is based on indices or other securities).
In abnormal market conditions, the Fund may take temporary defensive measures -
such as holding unusually large amounts of cash and cash equivalents - that are
inconsistent with the Fund's primary investment strategy. In taking those
measures, the Fund may not achieve its investment goal.
- -----------------------------------------------------------------
SUBADVISER
MORGAN STANLEY DEAN WITTER INVESTMENT MANAGEMENT INC.
1221 Avenue of the
Americas New York, New York, 10020
Managing since 1975
Managed over $160 billion in assets at the end of 1998
FUND MANAGERS
ROBERT L. MEYER, CFA
- --------------------
Managing Director of subadviser
Joined subadviser in 1989
ANDY SKOV
- ---------
Principal of subadviser
Joined subadviser in 1994
1
<PAGE>
MAIN RISKS
The following risks are major factors in the Fund's performance:
Foreign Risk: The Fund's foreign securities will pose special risks, due to
limited government regulation, lack of public information, economic, political
and social instability and foreign currency rate fluctuations. Factors such as
lack of liquidity, foreign ownership limits and restrictions on removing
currency also pose special risks. All foreign securities have some degree of
foreign risk. However, since the Fund invests primarily in emerging market
countries, it will have a significantly higher degree of foreign risk than funds
that invest primarily in developed or newly- industrialized countries.
Market Risk: The value of the securities in the Fund may go down in response to
overall stock or bond market movements. Markets tend to move in cycles, with
periods of rising prices and periods of falling prices. Stocks tend to go up
and down in value more than bonds. If the Fund's investments are concentrated
in certain sectors, the Fund's performance could be worse than the overall
market.
Manager Risk: The manager and its strategy may fail to produce the intended
results. The Fund could underperform its peers or lose money if the manager's
investment strategy does not perform as expected.
The following risk is not considered a major factor in the Fund's performance
because the Fund would not normally commit a large portion of its assets to the
investments involved. However, the risk is of such a nature that it could
significantly affect the Fund's performance, even if the investments are held in
relatively small amounts:
Derivatives Risk: Certain derivative instruments (such as options, futures and
swaps) can produce disproportionate gains or losses. They are generally
considered more risky than direct equity investments. Also, in a down market,
derivatives could become harder to value or sell at a fair price.
-------------------------------------
The following risk is considered significant because of its potential impact on
the Fund's performance:
Turnover Risk: In general, the greater the volume of buying and selling by a
fund (i.e., the higher its "turnover rate"), the greater the impact that
brokerage commissions and other transaction costs will have on the fund's
performance. Any turnover rate in excess of 100% is considered relatively high.
The Fund's turnover rate could be greater than 100% due to the relatively high
volatility associated with investing in emerging markets.
2. THE REFERENCE TO "MONTGOMERY ASSET MANAGEMENT, LLC" APPEARING ON PAGE 54 OF
THE PROSPECTUSES IS REVISED TO READ AS FOLLOWS: "MORGAN STANLEY DEAN WITTER
INVESTMENT MANAGEMENT INC."
3. THE EMERGING MARKETS EQUITY COMPOSITE APPEARING ON PAGE 57 OF THE
PROSPECTUSES IS REVISED TO READ AS FOLLOWS:
EMERGING MARKETS EQUITY COMPOSITE (Corresponding to Emerging Markets Equity
Fund)
The Emerging Markets Equity Composite is an asset-weighted composite of all
fully discretionary accounts (excluding the Emerging Markets Equity Fund and all
other separately managed accounts) managed using a substantially similar
investment strategy . As of December 31, 1998, the composite included 11
accounts with total assets of $3 billion.
Year-by-year total returns -- calendar years
[BAR GRAPH APPEARS HERE]
BEST QUARTER: up 19.21%, second quarter 1994
WORST QUARTER: down 23.58%, second quarter 1998
Average annual total returns -- for periods ending 12/31/98
<TABLE>
<CAPTION>
COMPOSITE INDEX
<S> <C> <C>
1 year -21.69% -25.34%
3 years -5.41% -11.21%
5 years -4.95% - 9.27%
</TABLE>
INDEX: MSCI Emerging Markets Free Index
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
2
