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                            VAN KAMPEN RESERVE FUND
                    SUPPLEMENT DATED AUGUST 28, 2001 TO THE
                      PROSPECTUS DATED SEPTEMBER 28, 2000
                       SUPERCEDING ALL PRIOR SUPPLEMENTS

    The Prospectus is hereby supplemented as follows:

    (1) The second paragraph under the heading "PURCHASE OF SHARES -- GENERAL"
is hereby deleted in its entirety.

    (2) The following is added as the last paragraph under the heading "PURCHASE
OF SHARES -- GENERAL":

        There is no minimum investment amount when establishing an account with
    the Fund. However, the Fund may redeem any shareholder account (other than
    retirement accounts and accounts established through a broker for which the
    transfer agent does not have discretion to initiate transactions) that has
    been open for one year or more and has a balance of less than $1,000.
    Shareholders will receive written notice at least 60 days in advance of any
    involuntary redemption and will be given the opportunity to purchase at net
    asset value without sales charge the number of additional shares needed to
    bring the account value to $1,000. There will be no involuntary redemption
    if the value of the account is less than $1,000 due to market depreciation.

    (3) The section entitled "REDEMPTION OF SHARES -- OTHER REDEMPTION
INFORMATION" is hereby deleted in its entirety.

    (4) The last four sentences of the sixth paragraph under the heading
"SHAREHOLDER SERVICES -- EXCHANGE PRIVILEGE" are hereby deleted in their
entirety and replaced with the following:

        The Fund reserves the right to reject any order to purchase its shares
    through exchange or otherwise. Certain patterns of past exchanges and/or
    purchase or sale transactions involving the Fund or other Participating
    Funds may result in the Fund and other Participating Funds limiting or
    prohibiting, at its discretion, additional purchases and/or exchanges.
    Determinations in this regard may be made based on the frequency or dollar
    amount of the previous exchanges or purchases or sale transactions.
    Generally, all shareholders are limited to a maximum of eight exchanges per
    fund during a rolling 365-day period. Exchange privileges will be suspended
    on a particular fund if more than eight exchanges out of that fund are made
    by a shareholder during a rolling 365-day period. If exchange privileges are
    suspended, subsequent exchange requests during the stated period will not be
    processed. Exchange privileges will be restored when the account history
    shows fewer than eight exchanges in
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    the rolling 365-day period. This eight exchange policy does not apply to
    money market funds, systematic exchange plans or employer-sponsored
    retirement plans. The fund may modify, restrict or terminate the exchange
    privilege at any time. Shareholders will receive 60 days' notice of any
    termination or material amendment.

    (5) The information on the inside back cover of the Prospectus under the
heading "BOARD OF TRUSTEES AND OFFICERS" is hereby amended by deleting Fernando
Sisto, effective December 31, 2000.

    (6) Richard A. Ciccarone is no longer an officer of the Fund. The
information on the inside back cover of the Prospectus under the heading "BOARD
OF TRUSTEES AND OFFICERS" is hereby amended by deleting the OFFICERS section in
its entirety and revising the heading to "BOARD OF TRUSTEES".

                  RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE

                                                                    RES SPT 8/01
                                                                      23 133 233
                                                                        65138-01