LIBERTY ACORN TRUST
                     RULE 12B-1 PLAN IMPLEMENTING AGREEMENT

      Liberty Acorn Trust ("Trust"), on behalf of each series (each a "Fund") of
the Trust designated in Appendix 1 from time to time, acting severally, and
Liberty Funds Distributor, Inc. ("LFDI"), a Massachusetts corporation, agree as
of November 1, 2001:

      1. 12B-1 PLAN. The Trust, on behalf of its Funds, has adopted [one or
more] "Rule l2b-1 Plan[s]" (each, a "Plan") pursuant to Rule l2b-1 (the "Rule")
under the Investment Company Act of 1940 (the "Act"). Under the Rule, a Fund
may, pursuant to a Plan, pay LFDI a specified portion of the assets attributable
to a class of shares of that Fund ("Class of Shares") to be used for the
purposes specified in the Plan. A Plan shall continue in effect with respect to
a Class of Shares only so long as specifically approved for that Class at least
annually as provided in the Rule. A Plan may not be amended to increase
materially the service fee or distribution fee with respect to a Class of Shares
without such shareholder approval as is required by the Rule or any applicable
orders of the Securities and Exchange Commission, and all material amendments of
the Plan must be approved in the manner described in the Rule. A Plan may be
terminated with respect to a Class of Shares at any time as provided in the Rule
without payment of any penalty.

      This Agreement shall apply to each Fund named in Appendix 1 as that
Appendix may be amended from time to time by the parties, in writing.

      2. PAYMENTS, EXPENDITURES AND REPORTS.

            A. Each Fund shall pay LFDI the amount then due LFDI under a Plan on
the 20th day of each month, or, if such day is not a business day, the next
business day thereafter, during the term of this Agreement.

            B. LFDI shall expend the amounts paid to it by the Funds under a
Plan in its discretion, so long as such expenditures are consistent with the
Rule, the Plan, and any instructions LFDI may receive from the Trustees of the
Trust.

            C. LFDI shall make all reports required under the Act, the Rule or a
Plan to the Trustees of the Trust, as provided in the Act, the Rule and any Plan
or as requested by the Trustees.

      3. CONTINUATION; AMENDMENT; TERMINATION; NOTICE.

            A. This Agreement (i) supersedes and replaces any contract or
agreement relating to the subject matter hereof in effect prior to the date
hereof, (ii) shall continue in effect as to the Trust or a Fund only so long as
specifically approved at least annually by the Trustees or shareholders of the
Trust or Fund, and (iii) may be amended at any time by written agreement of the
parties, each in accordance with the Act and the Rule.

            B. This Agreement (i) shall terminate with respect to any Fund or
any Class of Shares immediately upon the effective date of any later dated
agreement, with respect to that Fund or Class of Shares, relating to the subject
matter hereof, (ii) may be terminated by the Trust with respect to one or more
Funds upon 60 days' notice without penalty by a vote of the Trustees of the
Trust or by LFDI or otherwise in accordance with the Act, and (iii) will
terminate immediately with respect to any party in the event of its assignment
by that party (as defined in the Act). Upon termination, the obligations of the
parties under this Agreement shall cease except for unfulfilled obligations and
liabilities arising prior to termination.

            C. All notices required under this Agreement shall be in writing and
delivered to the office of the other party.

      4. AGREEMENT AND DECLARATION OF TRUST. A copy of the document establishing
the Trust is filed with the Secretary of The Commonwealth of Massachusetts. As
to the Trust, this Agreement is executed by officers not as individuals and is
not binding upon any of the Trustees, officers or shareholders of the Trust
individually but only upon the assets of the relevant Fund.

Agreed:

LIBERTY ACORN TRUST                     LIBERTY FUNDS DISTRIBUTOR, INC.


By:  Bruce H. Lauer                     By:  James Tambone
     -------------------------------         -----------------------------------
     Vice President and Treasurer            Co-President


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APPENDIX 1

Liberty Acorn Fund
Liberty Acorn International
Liberty Acorn USA
Liberty Acorn Twenty
Liberty Acorn Foreign Forty


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