<PAGE>
BARR ROSENBERG SERIES TRUST
SUPPLEMENT DATED MARCH 20, 1998
TO
PROSPECTUS DATED JULY 18, 1997
This Supplement is provided to update, and should be read in conjunction
with, the information provided in the Prospectus.
Effective March 20, 1998, Adviser Shares of the International Small
Capitalization Series and the Japan Series of Barr Rosenberg Series Trust
will no longer be offered for sale to investors and will not be available for
exchange for Adviser Shares of the U.S. Small Capitalization Series.
SUPPLEMENT DATED FEBRUARY 23, 1998
TO
PROSPECTUS DATED JULY 18, 1997
Effective February 20, 1998 (the "Closing Date"), the U.S. Small
Capitalization Series has been closed to new investors (except as otherwise
provided below). The following categories of existing shareholders will
still be permitted to purchase shares of the U.S. Small Capitalization
Series: (i) shareholders who own shares of the U.S. Small Capitalization
Series on the Closing Date will be permitted to purchase additional shares of
the U.S. Small Capitalization Series for as long as they continue to own
shares of such Fund; (ii) shareholders who beneficially own shares of the
U.S. Small Capitalization Series on the Closing Date through a registered
investment adviser or financial adviser will be permitted to purchase
additional shares of the U.S. Small Capitalization Series for as long as they
beneficially own shares of such Fund; (iii) participants in any self-directed
qualified benefit plan (for example, 401(a), 401(k), 457 and 403(b) plans)
will be eligible to direct the purchase of the shares of the U.S. Small
Capitalization Series by their plan account for as long as the plan continues
to own shares of such Fund for any single plan participant; and (iv)
participants in certain "wrap programs" that have entered into contractual
arrangements with the Trust and/or Distributor will be eligible to purchase
shares of the U.S. Small Capitalization Series for as long as the "wrap
program" continues to own shares of such Fund.
In the event (i) a shareholder redeems all of his, her or its shares of
the U.S. Small Capitalization Series; (ii) a shareholder who beneficially
owns shares of such Fund through a registered investment adviser or financial
adviser redeems all of his, her or its shares of such Fund; (iii) all
participants in a benefit plan described above redeem their shares of such
Fund; and (iv) a "wrap program" described above ceases to own shares of such
Fund, such shareholder who beneficially owns shares through a registered
investment adviser or financial adviser, the participants in such benefit
plan, and the participants in such "wrap program", respectively, will no
longer be eligible to purchase shares of the U.S. Small Capitalization Series.
Shareholders of other Funds will not be permitted to exchange any of
their shares for shares of the U.S. Small Capitalization Series unless such
shareholders are independently eligible to purchase shares of the U.S. Small
Capitalization Series as described above. The Trust reserves the right at
any time to modify the restrictions set forth above, including the suspension
of all sales of shares of the U.S. Small Capitalization Series or the lifting
of restrictions on different classes of investors and/or transactions.
