<PAGE>
SUPPLEMENT DATED DECEMBER 1, 1998
TO PROSPECTUSES DATED MAY 1, 1998
AS AMENDED AND SUPPLEMENTED TO DATE
OF
<TABLE>
<CAPTION>
EUROPEAN REAL ESTATE PORTFOLIO MUNICIPAL BOND PORTFOLIO
<S> <C>
ASIAN REAL ESTATE PORTFOLIO MORTGAGE-BACKED SECURITIES PORTFOLIO
U.S. REAL ESTATE PORTFOLIO MONEY MARKET PORTFOLIO
ASIAN EQUITY PORTFOLIO MUNICIPAL MONEY MARKET PORTFOLIO
JAPANESE EQUITY PORTFOLIO EQUITY GROWTH PORTFOLIO
EMERGING MARKETS PORTFOLIO EMERGING GROWTH PORTFOLIO
EMERGING MARKETS DEBT PORTFOLIO AGGRESSIVE EQUITY PORTFOLIO
LATIN AMERICAN PORTFOLIO VALUE EQUITY PORTFOLIO
GLOBAL EQUITY PORTFOLIO GLOBAL FIXED INCOME PORTFOLIO
INTERNATIONAL EQUITY PORTFOLIO HIGH YIELD PORTFOLIO
ACTIVE INTERNATIONAL ALLOCATION
INTERNATIONAL SMALL CAP PORTFOLIO PORTFOLIO
EUROPEAN EQUITY PORTFOLIO TECHNOLOGY PORTFOLIO
U.S. EQUITY PLUS PORTFOLIO GOLD PORTFOLIO
INTERNATIONAL MAGNUM PORTFOLIO CHINA GROWTH PORTFOLIO
FIXED INCOME PORTFOLIO MICROCAP PORTFOLIO
</TABLE>
PORTFOLIOS OF THE
MORGAN STANLEY INSTITUTIONAL FUND, INC.
P.O. BOX 2798
BOSTON, MASSACHUSETTS
02208-2798
-------------
The Prospectuses are hereby amended and supplemented to reflect the
following:
Effective December 1, 1998, Morgan Stanley Institutional Fund, Inc. (the
"Fund") has changed its name to Morgan Stanley Dean Witter Institutional Fund,
Inc.
Effective December 1, 1998, Morgan Stanley Asset Management Inc., the Fund's
investment adviser, has changed its name to Morgan Stanley Dean Witter
Investment Management Inc.
--------------
PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE
<PAGE>
SUPPLEMENT DATED DECEMBER 1, 1998
TO STATEMENT OF ADDITIONAL INFORMATION DATED MAY 1, 1998
AS AMENDED AND SUPPLEMENTED TO DATE
OF
<TABLE>
<CAPTION>
EUROPEAN REAL ESTATE PORTFOLIO MUNICIPAL BOND PORTFOLIO
<S> <C>
ASIAN REAL ESTATE PORTFOLIO MORTGAGE-BACKED SECURITIES PORTFOLIO
U.S. REAL ESTATE PORTFOLIO MONEY MARKET PORTFOLIO
ASIAN EQUITY PORTFOLIO MUNICIPAL MONEY MARKET PORTFOLIO
JAPANESE EQUITY PORTFOLIO EQUITY GROWTH PORTFOLIO
EMERGING MARKETS PORTFOLIO EMERGING GROWTH PORTFOLIO
EMERGING MARKETS DEBT PORTFOLIO AGGRESSIVE EQUITY PORTFOLIO
LATIN AMERICAN PORTFOLIO VALUE EQUITY PORTFOLIO
GLOBAL EQUITY PORTFOLIO GLOBAL FIXED INCOME PORTFOLIO
INTERNATIONAL EQUITY PORTFOLIO HIGH YIELD PORTFOLIO
ACTIVE INTERNATIONAL ALLOCATION
INTERNATIONAL SMALL CAP PORTFOLIO PORTFOLIO
EUROPEAN EQUITY PORTFOLIO TECHNOLOGY PORTFOLIO
U.S. EQUITY PLUS PORTFOLIO GOLD PORTFOLIO
INTERNATIONAL MAGNUM PORTFOLIO CHINA GROWTH PORTFOLIO
FIXED INCOME PORTFOLIO MICROCAP PORTFOLIO
</TABLE>
PORTFOLIOS OF THE
MORGAN STANLEY INSTITUTIONAL FUND, INC.
P.O. BOX 2798
BOSTON, MASSACHUSETTS
02208-2798
-------------
The Statement of Additional Information is hereby amended and supplemented
to reflect the following:
Effective December 1, 1998, Morgan Stanley Institutional Fund, Inc. (the
"Fund") has changed its name to Morgan Stanley Dean Witter Institutional Fund,
Inc.
Effective December 1, 1998, Morgan Stanley Asset Management Inc., the Fund's
investment adviser, has changed its name to Morgan Stanley Dean Witter
Investment Management Inc.
--------------
PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE
