<PAGE>
SUPPLEMENT DATED FEBRUARY 24, 1998
TO PROSPECTUS DATED MAY 1, 1997
AS SUPPLEMENTED THROUGH SEPTEMBER 26, 1997
ASIAN EQUITY PORTFOLIO
JAPANESE EQUITY PORTFOLIO
PORTFOLIOS OF THE
MORGAN STANLEY INSTITUTIONAL FUND, INC. (THE "FUND")
P.O. BOX 2798
BOSTON, MASSACHUSETTS
02208-2798
-------------
The Prospectus is being amended and supplemented to reflect a change in the
portfolio management of the Asian Equity Portfolio. Vinod Sethi now shares
primary responsibility for managing the assets of the Asian Equity Portfolio
with Ean Wah Chin. Accordingly, the third paragraph on page 21 is hereby deleted
and replaced with the following:
ASIAN EQUITY PORTFOLIO -- EAN WAH CHIN AND VINOD SETHI. Ean Wah
Chin is a Managing Director of Morgan Stanley and the Adviser. She has
been primarily responsible for managing the Portfolio's assets since its
inception. Prior to joining Morgan Stanley in 1986, Ms. Chin spent eight
years with the Monetary Authority of Singapore and the Government of
Singapore Investment Corporation, where she was a portfolio manager of
one of the largest portfolios in Asia. Vinod Sethi joined the Adviser in
1989 and since then, has been actively involved in the Adviser's
emerging markets group. Mr. Sethi is a Managing Director of Morgan
Stanley and the Adviser and is the Adviser's Chief Investment Officer
for the Asian region. He received his undergraduate degree in Chemical
Engineering from I.I.T. (Bombay) and his M.B.A. from New York University
School of Business.
--------------
PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE
