<PAGE>
T. Rowe Price Index Trust, Inc.
T. Rowe Price Equity Index 500 Fund
Supplement to Statement of Additional Information dated May 1, 2000, revised to
August 31, 2000
--------------------------------------------------------------------------------
Effective January 1, 2001, the expense limitation table on page 53 of the
Statement of Additional Information will be revised with the following to
reflect the extension of the expense ratio limitation for the Equity Index 500
Fund:
<TABLE>
<CAPTION>
Expense Reimbursement
Fund Limitation Period ------- -------------
---- ----------------- Ratio Date
------------------------------------------------ ----- ----
Limitation
----------
-------------------------------
<S> <S> <C> <S>
Equity Index 500(b) January 1, 2001 - 0.35% December 31, 2004
December 31, 2002
-------------------------------------------------------------------------------
</TABLE>
(b) The Equity Index 500 Fund previously operated under a 0.35%
limitation that expired December 31, 2000. The reimbursement period
for this limitation extends through December 31, 2001.
Pursuant to the Equity Index 500 Fund's previous expense limitation, $317,000
of management fees were not accrued by the fund for the year ended December
31, 1999. Additionally, $955,000 of unaccrued management fees remain subject
to reimbursement through December 31, 2001.
--------------------------------------------------------------------------------
The date of the above supplement is December 15, 2000.
--------------------------------------------------------------------------------
C20-045 12/15/00
