<PAGE>
LM Institutional Fund Advisors I, Inc.
100 Light St.
Baltimore, MD 21202
Supplement dated February 16, 2000 to
Prospectus dated August 1, 1999
Effective March 1, 2000, the Western Asset Intermediate Portfolio, Western Asset
Intermediate Plus Portfolio, Western Asset Core Portfolio and Western Asset Core
Plus Portfolio will declare dividends of net investment income daily and pay
such dividends monthly. Distributions of net realized capital gains of each of
these Portfolios will be made annually.