ACORN FUND
                              ACORN INTERNATIONAL
                                   ACORN USA
                                 ACORN TWENTY
                              ACORN FOREIGN FORTY


                         Supplement dated July 7, 2000
           to Prospectus dated May 1, 2000 of Acorn Investment Trust

     PROPOSED ADVISORY AGREEMENT. As of June 9, 2000, Wanger Asset Management,
L.P. ("WAM"), the Funds' investment adviser, and Wanger Asset Management, Ltd.,
the general partner of WAM, entered into an Agreement and Plan of Merger
("Merger Agreement") with Liberty Financial Companies, Inc. ("Liberty") and WAM
Acquisition L.P., a newly formed limited partnership ("Liberty Sub"). Under the
Merger Agreement, Liberty Sub would be merged with and into WAM (the "Merger").
WAM would be the surviving entity and would be a wholly-owned subsidiary of
Liberty. After the merger, WAM will operate under the name Liberty Wanger Asset
Management, L.P. ("Liberty WAM").

     On July 6, 2000, the Acorn trustees (on behalf of each of the Funds)
approved a new investment advisory agreement with Liberty WAM (the "Proposed
Advisory Agreement") that, if approved by shareholders, will become effective
upon the consummation of the Merger (the "Effective Date"). You will receive a
proxy statement describing the Merger and the Proposed Advisory Agreement in
more detail and seeking approval of the Proposed Advisory Agreement by the
shareholders of each Fund. The Merger Agreement provides that the Merger is
conditioned upon the shareholders of each of Acorn Fund, Acorn International and
Acorn USA approving the Proposed Advisory Agreement and certain other conditions
are met.

     MULTIPLE CLASSES OF SHARES. The Acorn trustees also authorized the offering
of multiple classes of shares for each of the Acorn Funds beginning on the
Effective Date. Existing Fund shares will be designated Class Z shares as of the
Effective Date. Class Z shares will continue to be sold without any sales load
and to have the same privileges as are currently provided (except as provided
below). Holders of an existing account on the Effective Date will remain
eligible to purchase Class Z shares of each Acorn fund as long as the
shareholder continuously holds Class Z shares of a Fund. Class Z shares will
also be available for purchase by members of the families of existing Acorn
shareholders who continue to hold Class Z shares, by certain institutional
investors and by certain other eligible investors described from time to time in
the Funds' prospectuses. Class Z shares generally will not be available for
purchase by other new investors after the Effective Date. More information about
persons eligible to purchase Class Z shares will be included in a new Acorn
funds prospectus that will be sent to all shareholders promptly after the
Effective Date.

     EXCHANGE PRIVILEGE. After the Effective Date, no additional exchanges from
the Acorn funds to the Reich & Tang money market funds will be permitted.
Instead, Acorn shareholders will have the ability to exchange their Acorn Class
Z shares for shares of one or more money market funds managed by affiliates of
Liberty. Holders of Acorn Class Z shares will also have the ability to exchange
their shares for shares of certain other mutual funds managed by affiliates of
Liberty. More information about the exchange privilege will be included in a new
Acorn funds prospectus that will be sent to all shareholders promptly after the
Effective Date.

     NAME CHANGES. As of the Effective Date, the Funds' names will be changed to
"Liberty Acorn Fund," "Liberty Acorn International," "Liberty Acorn USA,"
"Liberty Acorn Twenty," and "Liberty Acorn Foreign Forty", respectively. The
name of Acorn Investment Trust will be changed to "Liberty Acorn Investment
Trust."

     ANTICIPATED EFFECTIVE DATE. Subject to the receipt of the necessary
shareholder approvals and the satisfaction of other conditions contained in the
Merger Agreement, it is anticipated that the Effective Date will occur as soon
as reasonably practicable after the requisite shareholder approvals have been
obtained.



                           ACORN INVESTMENT TRUST

                       Supplement dated July 7, 2000 to
                      Statement of Additional Information
                               dated May 1, 2000

     WAM Brokerage Services, L.L.C., distributor of the shares of each of the
Acorn funds, may from time to time sponsor contests, drawings or sweepstakes in
which shares of one or more of the Acorn funds may be awarded as prizes. Any
shares so awarded will be purchased by WAM Brokerage Services, on the same terms
on which shares are made available for purchase by others, and transferred to
one or more persons selected as the winner or winners of such contests, drawings
or sweepstakes, or WAM Brokerage Services may pay for fund shares to be issued
directly to such winner or winners. Any such contest, drawing or sweepstakes
will be conducted without cost to the funds, which will receive the full net
asset value of any shares so awarded.