<PAGE>
The Munder Funds
Supplement Dated September 18, 2000
to Prospectus Dated April 28, 2000
Class K Shares of:
Munder Institutional S&P 500 Index Equity Fund,
Munder Institutional S&P MidCap Index Equity Fund,
Munder Institutional S&P SmallCap Index Equity Fund,
Munder Institutional Short Term Treasury Fund
and Munder Institutional Money Market Fund
CHANGE IN PORTFOLIO MANAGEMENT OF
MUNDER INSTITUTIONAL S&P SMALLCAP INDEX EQUITY FUND
Kenneth A. Schluchter III and Brian Kozeliski jointly manage the Fund. Mr.
Schluchter, Director of Domestic Investments of the advisor, has managed the
Fund since its inception. He was previously a systems developer and data
analyst for Compuware Incorporated (1993-1995). Mr. Kozeliski, a portfolio
manager of the advisor, has jointly managed the Fund since July, 2000. Prior to
joining the advisor in 1999, Mr. Kozeliski was a Business Analyst at
Continental Promotion Group (1998-1999), a Web Page Administrator at American
Graduate School of Int'l Management (1997-1998) and a Customer Support Manager
for Sykes Enterprises Inc. (1995-1997).
SUPPPROINSTK900
<PAGE>
The Munder Funds
Supplement Dated September 18, 2000
to Prospectus Dated April 28, 2000
Class Y Shares of:
Munder Institutional S&P 500 Index Equity Fund,
Munder Institutional S&P MidCap Index Equity Fund,
Munder Institutional S&P SmallCap Index Equity Fund,
Munder Institutional Short Term Treasury Fund
and Munder Institutional Money Market Fund
CHANGE IN PORTFOLIO MANAGEMENT OF
MUNDER INSTITUTIONAL S&P SMALLCAP INDEX EQUITY FUND
Kenneth A. Schluchter III and Brian Kozeliski jointly manage the Fund. Mr.
Schluchter, Director of Domestic Investments of the advisor, has managed the
Fund since its inception. He was previously a systems developer and data
analyst for Compuware Incorporated (1993-1995). Mr. Kozeliski, a portfolio
manager of the advisor, has jointly managed the Fund since July, 2000. Prior to
joining the advisor in 1999, Mr. Kozeliski was a Business Analyst at
Continental Promotion Group (1998-1999), a Web Page Administrator at American
Graduate School of Int'l Management (1997-1998) and a Customer Support Manager
for Sykes Enterprises Inc. (1995-1997).
SUPPPROINSTY900
