<PAGE>
SEI INSTITUTIONAL MANAGED TRUST
SMALL CAP VALUE FUND
SMALL CAP GROWTH FUND
SUPPLEMENT DATED APRIL 12, 1999
TO THE CLASS A PROSPECTUS DATED JANUARY 31, 1999
THIS SUPPLEMENT PROVIDES NEW AND ADDITIONAL INFORMATION BEYOND THAT CONTAINED IN
THE PROSPECTUS, AND SHOULD BE READ IN CONJUNCTION WITH SUCH PROSPECTUS.
---------------------------------------------------------
The Board of Trustees of SEI Institutional Managed Trust (the "Trust"),
including all of the Trustees who are not "interested persons" of the Trust,
have appointed Artisan Partners Limited Partnership ("Artisan Partners"), as a
Sub-Adviser to the Trust's Small Cap Value Fund (the "Fund"). Artisan Partners
was approved as a Sub-Adviser at the Quarterly Meeting of the Board of Trustees
held on March 29-30, 1999, and its appointment does not require Shareholder
approval. This procedure for adding or replacing Sub-Advisers was approved by
the Trust's Shareholders on April 28, 1995, and was authorized by an exemptive
order issued to the Trust by the Securities and Exchange Commission on April 29,
1996.
In evaluating Artisan Partners, the Trustees received written and oral
information from SEI Investments Management Corporation ("SIMC") and Artisan
Partners. SIMC recommended the selection of Artisan Partners and reviewed the
considerations and the search process that led to its recommendation. The
Trustees also met with representatives of Artisan Partners and considered
information about portfolio managers, investment philosophy, strategies and
process, as well as its performance track record, among other factors. In
appointing Artisan Partners, the Trustees carefully evaluated: (1) the nature
and quality of the services expected to be rendered to the Fund by Artisan
Partners; (2) the distinct investment objective and policies of the Fund; (3)
the history, reputation, qualification and background of Artisan Partners's
personnel and its financial condition; (4) its performance record; and (5) other
factors deemed relevant. The Trustees also reviewed the fees to be paid to
Artisan Partners, including any benefits to be received by Artisan Partners or
its affiliates in connection with soft dollar arrangements.
Under the Investment Sub-Advisory Agreement ("Sub-Advisory Agreement") between
SIMC (the "Adviser") and Artisan Partners relating to the Fund, Artisan Partners
makes investment decisions for the assets of the Fund allocated to Artisan
Partners by SIMC, and continuously reviews, supervises and administers the
Fund's investment program with respect to these assets. Artisan Partners is
independent of SIMC and discharges its responsibilities subject to the
supervision of SIMC and the Trustees of the Trust and in a manner consistent
with the Fund's investment objectives, policies and limitations. The
Sub-Advisory Agreement is substantially similar to those in existence between
the Adviser and the Trust's other sub-advisers. Specifically, the duties to be
performed under such agreement are similar, and the standard of care and
termination provisions of the Agreement are identical, to the other agreements.
The Sub-Advisory Agreement will remain in effect until March 2001 (unless
earlier terminated), and will have to be approved annually thereafter by a
majority of the Trust's Trustees, including a majority of the Trustees who are
not "interested persons" of the Trust (as defined in the Investment Company Act
of 1940).
At the same Meeting, the Trustees determined to terminate 1838 Investment
Advisors, Inc. ("1838"), one of the Fund's current Sub-Advisers. In determining
to terminate 1838, the Trustees reviewed information provided by SIMC relating
to 1838's investment performance and its adherence to its stated investment
discipline.
In connection with the termination of 1838 and the appointment of Artisan
Partners as Sub-Adviser to the Fund, the "Sub-Advisers" Section on page 21 of
the Prospectus is amended by inserting the following disclosure relating to
Artisan Partners and removing the description of 1838:
ARTISAN PARTNERS LIMITED PARTNERSHIP: Scott C. Satterwhite, managing director of
Artisan Partners Limited Partnership ("Artisan Partners"), serves as a portfolio
manager of a portion of the assets of the Small Cap Value Fund. Mr. Satterwhite
has over 15 years of investment experience, the last six of which have been
dedicated to small-cap value investing.
SEI-A-101-05
<PAGE>
Artisan Partners is a limited partnership that was founded in 1994. The general
partner of Artisan Partners is Artisan Investment Corp., a corporation
controlled by Andrew Ziegler and Carlene Ziegler, Managing Partners of Artisan
Partners. As of December 31, 1998, Artisan Partners had approximately $1.35
billion in assets under management.
Listed below are the names and principal occupations of the principal executive
officer and each of the Managing Directors of Artisan Partners. The principal
business address of the principal executive officer and each of the Managing
Directors, as it relates to their positions at Artisan Partners, is 1000 N.
Water Street, Milwaukee, Wisconsin 53202
<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------
NAME TITLE
- -----------------------------------------------------------------------------------------------------------------
<S> <C>
Andrew A. Ziegler Chief Executive Officer
- -----------------------------------------------------------------------------------------------------------------
Lawrence A Totsky Chief Financial Officer
- -----------------------------------------------------------------------------------------------------------------
Mark L. Yockey Portfolio Manager
- -----------------------------------------------------------------------------------------------------------------
Carlene M. Ziegler Portfolio Manager
- -----------------------------------------------------------------------------------------------------------------
Millie A. Hurwitz Portfolio Manager
- -----------------------------------------------------------------------------------------------------------------
Scott C. Satterwhite Portfolio Manager
- -----------------------------------------------------------------------------------------------------------------
Andrew C. Stephens Portfolio Manager
- -----------------------------------------------------------------------------------------------------------------
Robert M. Clark Marketing & Client Service
- -----------------------------------------------------------------------------------------------------------------
Darren W. DeVore Marketing & Client Service
- -----------------------------------------------------------------------------------------------------------------
Michael Steinrueck Marketing & Client Service
- -----------------------------------------------------------------------------------------------------------------
Michael C. Roos Marketing & Client Service
- -----------------------------------------------------------------------------------------------------------------
</TABLE>
The Adviser will pay Artisan Partners a fee based on a percentage of the average
monthly market value of the assets of the Fund assigned to Artisan Partners.
----------------------------------------------------------------
At the same Meeting, the Trustees appointed Sawgrass Asset Management, L.L.C.
("Sawgrass"), as a Sub-Adviser to the Trust's Small Cap Growth Fund (the
"Fund"). Sawgrass' appointment does not require Shareholder approval.
In evaluating Sawgrass, the Trustees received written and oral information from
both SIMC and Sawgrass. SIMC recommended the selection of Sawgrass and reviewed
the considerations and search process that led to its recommendation. The
Trustees also met with representatives of Sawgrass and considered information
about portfolio managers, investment philosophy, strategies and process, as well
as other factors. In appointing Sawgrass, the Trustees carefully evaluated: (1)
the nature and quality of the services expected to be rendered to the Fund by
Sawgrass; (2) the distinct investment objective and policies of the Fund; (3)
the history, reputation, qualification and background of Sawgrass's personnel
and its financial condition; (4) its performance track record; and (5) other
factors deemed relevant. The Trustees also reviewed the fees to be paid to
Sawgrass, including any benefits to be received by Sawgrass or its affiliates in
connection with soft dollar arrangements.
Under the Investment Sub-Advisory Agreement ("Sub-Advisory Agreement") between
SIMC (the "Adviser") and Sawgrass relating to the Fund, Sawgrass makes
investment decisions for the assets of the Fund allocated to it by SIMC, and
continuously reviews, supervises and administers the Fund's investment program
with respect to these assets. Sawgrass is independent of SIMC and discharges its
responsibilities subject to the supervision of SIMC and the Trustees of the
Trust, and in a manner consistent with the Fund's investment objective, policies
and limitations. The Sub-Advisory Agreement is substantially similar to those in
existence between the Adviser and the Trust's other Sub-Advisers. Specifically,
the duties to be performed under each Agreement are similar, and the standard of
care and termination provisions of the Agreement are identical to the other
Agreements. The Sub-Advisory Agreement will remain in effect until March 2001
(unless earlier terminated), and will have to be approved annually thereafter by
a majority of the Trustees, including a majority of the Trustees who are not
"interested persons" of the Trust (as defined in the Investment Company Act of
1940).
<PAGE>
At the same Meeting, the Trustees determined to terminate Spyglass Asset
Management, Inc. ("Spyglass"), one of the Fund's current Sub-Advisers. Spyglass
was terminated due to its inability to provide sufficient investment capacity to
the Fund. Spyglass remains a Sub-Adviser for another Fund advised by SIMC.
In connection with the termination of Spyglass and the appointment of Sawgrass
as Sub-Adviser to the Fund, the "Sub-Advisers" Section on page 22 of the
Prospectus is amended by inserting the following disclosure relating to Sawgrass
and removing the description of Spyglass:
SAWGRASS ASSET MANAGEMENT, L.L.C.: Dean E. McQuiddy, a principal and portfolio
manager of Sawgrass Asset Management, L.L.C. ("Sawgrass"), serves as lead
portfolio manager of a portion of the assets of the Small Cap Growth Fund. Mr.
McQuiddy has 12 years of portfolio management experience.
Sawgrass is a Delaware limited liability company that was founded in 1998.
Sawgrass is controlled by its principals, Andrew Cantor, Dean McQuiddy and Brian
Monroe. AmSouth Bancorporation is a passive equity investor in Sawgrass, and
will decrease its share stake in Sawgrass from 50% to 27.5% over time. As of
December 31, 1998, Sawgrass had approximately $230 million in assets under
management.
Listed below are the names and principal occupations of the partners and
principals of Sawgrass. The principal business address of the partners and
principals, as it relates to their positions at Sawgrass, is 4337 Pablo Oaks
Court, Building 200, Jacksonville, Florida 32224.
<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------
NAME TITLE
- -----------------------------------------------------------------------------------------------------------------
<S> <C>
Andrew M. Cantor Principal
- -----------------------------------------------------------------------------------------------------------------
Dean E. McQuiddy Principal
- -----------------------------------------------------------------------------------------------------------------
Brian K. Monroe Principal
- -----------------------------------------------------------------------------------------------------------------
Martin E. Laprade Partner
- -----------------------------------------------------------------------------------------------------------------
Joe Beattie, III Partner
- -----------------------------------------------------------------------------------------------------------------
Patrick A. Riley Partner
- -----------------------------------------------------------------------------------------------------------------
David A Furfine Partner
- -----------------------------------------------------------------------------------------------------------------
Janet B. Emmick Partner
- -----------------------------------------------------------------------------------------------------------------
Judy Z. Doyle Partner
- -----------------------------------------------------------------------------------------------------------------
</TABLE>
The Adviser will pay Sawgrass a fee based on a percentage of the average monthly
market value of the assets of the Fund assigned to Sawgrass.
----------------------------------------------------------------
The prospectus is hereby amended to reflect these changes.
PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE
<PAGE>
SEI INSTITUTIONAL MANAGED TRUST
SMALL CAP GROWTH FUND
SUPPLEMENT DATED APRIL 12, 1999
TO THE CLASS D PROSPECTUS DATED JANUARY 31, 1999
THIS SUPPLEMENT PROVIDES NEW AND ADDITIONAL INFORMATION BEYOND THAT CONTAINED IN
THE PROSPECTUS, AND SHOULD BE READ IN CONJUNCTION WITH SUCH PROSPECTUS.
---------------------------------------------------------
The Board of Trustees of SEI Institutional Managed Trust (the "Trust"),
including all of the Trustees who are not "interested persons" of the Trust,
have appointed Sawgrass Asset Management L.L.C. ("Sawgrass"), as a Sub-Adviser
to the Trust's Small Cap Growth Fund (the "Fund"). Sawgrass was approved as a
Sub-Adviser at the Quarterly Meeting of the Board of Trustees held on March
29-30, 1999, and its appointment does not require Shareholder approval. This
procedure for adding or replacing Sub-Advisers was approved by the Trust's
Shareholders on April 28, 1995, and was authorized by an exemptive order issued
to the Trust by the Securities and Exchange Commission on April 29, 1996.
In evaluating Sawgrass, the Trustees received written and oral information from
both SIMC and Sawgrass. SIMC recommended the selection of Sawgrass and reviewed
the considerations and search process that led to its recommendation. The
Trustees also met with representatives of Sawgrass and considered information
about portfolio managers, investment philosophy, strategies and process, as well
as other factors. In appointing Sawgrass, the Trustees carefully evaluated: (1)
the nature and quality of the services expected to be rendered to the Fund by
Sawgrass; (2) the distinct investment objective and policies of the Fund; (3)
the history, reputation, qualification and background of Sawgrass's personnel
and its financial condition; (4) its performance track record; and (5) other
factors deemed relevant. The Trustees also reviewed the fees to be paid to
Sawgrass, including any benefits to be received by Sawgrass or its affiliates in
connection with soft dollar arrangements.
Under the Investment Sub-Advisory Agreement ("Sub-Advisory Agreement") between
SIMC (the "Adviser") and Sawgrass relating to the Fund, Sawgrass makes
investment decisions for the assets of the Fund allocated to it by SIMC, and
continuously reviews, supervises and administers the Fund's investment program
with respect to these assets. Sawgrass is independent of SIMC and discharges its
responsibilities subject to the supervision of SIMC and the Trustees of the
Trust, and in a manner consistent with the Fund's investment objective, policies
and limitations. The Sub-Advisory Agreement is substantially similar to those in
existence between the Adviser and the Trust's other Sub-Advisers. Specifically,
the duties to be performed under each Agreement are similar, and the standard of
care and termination provisions of the Agreement are identical to the other
Agreements. The Sub-Advisory Agreement will remain in effect until March 2001
(unless earlier terminated), and will have to be approved annually thereafter by
a majority of the Trustees, including a majority of the Trustees who are not
"interested persons" of the Trust (as defined in the Investment Company Act of
1940).
At the same Meeting, the Trustees determined to terminate Spyglass Asset
Management, Inc. ("Spyglass"), one of the Fund's current Sub-Advisers. Spyglass
was terminated due to its inability to provide sufficient investment capacity to
the Fund. Spyglass remains a Sub-Adviser for another Fund advised by SIMC.
In connection with the termination of Spyglass and the appointment of Sawgrass
as Sub-Adviser to the Fund, the "Sub-Advisers" Section on page 22 of the
Prospectus is amended by inserting the following disclosure relating to Sawgrass
and removing the description of Spyglass:
SAWGRASS ASSET MANAGEMENT, L.L.C.: Dean E. McQuiddy, a principal and portfolio
manager of Sawgrass Asset Management, L.L.C. ("Sawgrass"), serves as lead
portfolio manager of a portion of the assets of the Small Cap Growth Fund. Mr.
McQuiddy has 12 years of portfolio management experience.
ACH-A-010-05
<PAGE>
Sawgrass is a Delaware limited liability company that was founded in 1998.
Sawgrass is controlled by its principals, Andrew Cantor, Dean McQuiddy and Brian
Monroe. AmSouth Bancorporation is a passive equity investor in Sawgrass, and
will decrease its share stake in Sawgrass from 50% to 27.5% over time. As of
December 31, 1998, Sawgrass had approximately $230 million in assets under
management.
Listed below are the names and principal occupations of the partners and
principals of Sawgrass. The principal business address of the partners and
principals, as it relates to their positions at Sawgrass, is 4337 Pablo Oaks
Court, Building 200, Jacksonville, Florida 32224.
<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------
NAME TITLE
- -----------------------------------------------------------------------------------------------------------------
<S> <C>
Andrew M. Cantor Principal
- -----------------------------------------------------------------------------------------------------------------
Dean E. McQuiddy Principal
- -----------------------------------------------------------------------------------------------------------------
Brian K. Monroe Principal
- -----------------------------------------------------------------------------------------------------------------
Martin E. Laprade Partner
- -----------------------------------------------------------------------------------------------------------------
Joe Beattie, III Partner
- -----------------------------------------------------------------------------------------------------------------
Patrick A. Riley Partner
- -----------------------------------------------------------------------------------------------------------------
David A Furtine Partner
- -----------------------------------------------------------------------------------------------------------------
Janet B. Emmick Partner
- -----------------------------------------------------------------------------------------------------------------
Judy Z. Doyle Partner
- -----------------------------------------------------------------------------------------------------------------
</TABLE>
The Adviser will pay Sawgrass a fee based on a percentage of the average monthly
market value of the assets of the Fund assigned to Sawgrass.
----------------------------------------------------------------
The prospectus is hereby amended to reflect these changes.
PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE
