0000836487 2013-01-29 2013-01-29 0000836487 ck0000836487:S000037170Member ck0000836487:S000037170Member 2013-01-29 2013-01-29 MORGAN STANLEY INSTITUTIONAL FUND INC Other false 0000836487 2013-01-29 2013-01-29 2013-01-29 2012-05-23 Multi-Asset Portfolio January 29, 2013 Morgan Stanley Institutional Fund, Inc. Supplement dated January 29, 2013 to the Morgan Stanley Institutional Fund, Inc. Prospectus dated May 23, 2012 of: Multi-Asset Portfolio (the "Portfolio") The following is hereby added as the penultimate paragraph under the section of the Prospectus entitled "Portfolio Summary - Principal Risks:" •  Non-Diversified Risk. Because the Portfolio is non-diversified, it may be more susceptible to an adverse event affecting a portfolio investment than a diversified portfolio and a decline in the value of that instrument would cause the Portfolio's overall value to decline to a greater degree. Because the Portfolio is non-diversified, it may be more susceptible to an adverse event affecting a portfolio investment than a diversified portfolio and a decline in the value of that instrument would cause the Portfolio's overall value to decline to a greater degree.