SCHEDULE 14A
                                (RULE 14A-101)
                           INFORMATION REQUIRED IN
                   PROXY STATEMENT SCHEDULE 14A INFORMATION

          Proxy Statement Pursuant to Section 14(a) of the Securities
                    Exchange Act of 1934 (Amendment No.  )

Filed by the Registrant [X]

Filed by a Party other than the Registrant [_]

Check the appropriate box:

[_]  Preliminary proxy statement.         [_]  CONFIDENTIAL, FOR USE OF THE
                                               COMMISSION ONLY (AS PERMITTED BY
                                               RULE 14A-6(E)(2)).
[_]  Definitive proxy statement.

[_]  Definitive additional materials.

[X]  Soliciting material under Rule 14a-12.

                            ACORN INVESTMENT TRUST
- --------------------------------------------------------------------------------
               (Name of Registrant as Specified In Its Charter)


- --------------------------------------------------------------------------------
   (Name of Person(s) Filing Proxy Statement, if other than the Registrant)


Payment of Filing Fee (Check the appropriate box):

[X]  No fee required.

[_]  Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.


     (1) Title of each class of securities to which transaction applies:

     -------------------------------------------------------------------------


     (2) Aggregate number of securities to which transaction applies:

     -------------------------------------------------------------------------


     (3) Per unit price or other underlying value of transaction computed
         pursuant to Exchange Act Rule 0-11 (set forth the amount on which
         the filing fee is calculated and state how it was determined):

     -------------------------------------------------------------------------


     (4) Proposed maximum aggregate value of transaction:

     -------------------------------------------------------------------------


     (5) Total fee paid:

     -------------------------------------------------------------------------

[_]  Fee paid previously with preliminary materials.

[_]  Check box if any part of the fee is offset as provided by Exchange
     Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee
     was paid previously. Identify the previous filing by registration statement
     number, or the Form or Schedule and the date of its filing.

     (1) Amount Previously Paid:

     -------------------------------------------------------------------------


     (2) Form, Schedule or Registration Statement No.:

     -------------------------------------------------------------------------


     (3) Filing Party:

     -------------------------------------------------------------------------


     (4) Date Filed:

     -------------------------------------------------------------------------





Liberty Financial FAQ                                                Page 1 of 3

What is this transaction all about?

Liberty Financial Companies is acquiring Wanger Asset Management, the investment
adviser to the Acorn Funds, not the Funds themselves. The same professionals
will continue to provide you with investment management and shareholder
services, simply as employees of a new Liberty operating company.

How will this merger affect me as an Acorn shareholder?

This transaction will have no effect on how you do business with Acorn Funds.
Therefore:

     .  the investment objective and portfolio manager of your fund will not
        change;
     .  the advisor fees and expenses charged by your fund will not change;
     .  the number and value of your fund shares will not change and you will
        continue to receive the same high quality investment management and
        shareholder services.

Who is Liberty Financial?

Liberty Financial is an asset accumulation and management organization. It
offers a broad array of brand name financial products through multiple
distribution channels via its highly regarded operating companies. The
operating companies include Colonial, Crabbe Huson, Independent Financial,
Keyport, Liberty Funds Group, Newport Pacific, Progress Investment Management
and Stein Roe. Liberty manages more than $67 billion of assets on behalf of 1.7
million investors worldwide.

Why did Wanger Asset Management decide to sell?

The sale of WAM was triggered in part by Ralph's desire to have a succession
plan in place. The goal was to find a relationship that would ensure WAMs
continued growth while maintaining the firms investment integrity and its
prominence as a highly regarded global small and midcap mutual fund company. The
substantial growth of the business over the last few years has made managing the
firm more challenging and is taking up an increasing amount of time. We believe
aligning with Liberty Financial Companies (LFC) ensures WAMs legacy in the
business and provides it access to powerful distribution networks and management
expertise. The sale strengthens WAMs ability to meet the growing needs of US
investors amid rising competition, and serves as a springboard for meeting the
increasing demand for investment management services worldwide.

Why did WAM select Liberty Financial?

Liberty Financial FAQ                                                Page 2 of 3


We wanted a partner that provides substantial strategic benefits with:

     .  An understanding of asset management;
     .  Distribution expertise and capabilities;
     .  Operational and strategic management expertise;
     .  Product breadth

Why did Liberty buy Wanger Asset Management?

Looking to grow its investment expertise, Liberty believes Wanger's small cap
and international discipline and historically strong performing mutual funds are
an ideal complement to its current product line.

As a shareholder, what do I get out of this?

You will continue to receive the same high quality investment management and
shareholder services that you have come to expect from Acorn Funds.
Additionally, we are excited about the prospect of enhancing the quality
investment products and services we offer you.

How will WAM be integrated into Liberty?

WAM will operate as a separate company alongside Liberty's other companies and
will continue to be run independently by current management. Therefore, the
investment objective and investment management team of the Acorn Funds will
remain the same.

Will this change the management of my funds?

No. The portfolio manager(s) of your fund will not change. The Funds' current
portfolio managers will continue to manage the Funds following the same
investment strategies and objectives currently in place. Each of the principals,
who are also fund managers, and Ralph Wanger, have signed five-year employment
contracts.

Will I have access to Liberty products?

Yes. We anticipate that Acorn shareholders will have exchange privileges with
65 Liberty funds.

Will Acorn remain headquartered in Chicago?

Yes.

Will I be able to continue to purchase shares without a sales load?

Yes.

Will I be asked to vote on the acquisition?

Yes. Once the trustees have approved the proposed agreement, shareholders will
receive a proxy statement asking them to vote on the approval on the new
investment advisory agreement to take effect upon the completion of the
acquisition. We expect


Liberty Financial FAQ                                               Page 3 of 3


the acquisition to close in the fourth quarter.

Will you rename the Funds or the organization?

After the closing of the merger, WAM would be a wholly owned subsidiary of
Liberty and would thereafter operate under the Liberty Wanger Asset Management,
L.P. (Liberty WAM). Wam will continue to be headquartered in Chicago and Ralph
Wanger would continue to act as president.

Will there be a 12b-1 fee after the acquisition? What about the funds' expense
ratios?

Shareholders of record at the time of the acquisition closing will be
"grandfathered" in at no-load status and will continue to be allowed to purchase
shares of the Acorn Family of Funds at no-load. We do not anticipate our expense
ratios to increase. In fact, as assets grow, the ratios could decrease.

After the acquisition early in the fourth quarter 2000, the funds will be load
funds. Liberty will decide the load structures, but since you are already an
Acorn shareholder, these loads or other fees will not affect you. You will
always have the privilege of buying Acorn Funds at no-load and hopefully other
Funds that Liberty offers as well.

List of Acorn Shareholder Benefits

It was recognized from the outset that any proposed plan would need to preserve
the current benefits to shareholders as well as provide them with incremental
long-term benefits.

     .  Ability for current shareholders to continue to acquire shares on
        current terms
     .  Maintain independence of current Board of Trustees
     .  Maintain current high level of customer service
     .  Continuity of investment team -- continuation of high-quality investment
        professionals at WAM -- who do not have to focus on the management of
        WAM
     .  Positive cash flow into funds; capital gains tax advantages via positive
        fund flows from long-term shareholders
     .  Increased shareholder confidence that at the point of RWs eventual
        retirement, WAM will continue to operate and adhere to RWs/WAMs
        investment style
     .  Enhanced shareholder services
     .  Assist in orderly succession planning
     .  Broader product offering to fulfill shareholder diversification
        preferences -- exchange privileges with 65 LFS funds
     .  Modern transfer agency system

To obtain more complete information about the Acorn Family of Funds, please call
1-800-9-ACORN-9. Please read the prospectus carefully before you invest or send
money.

Distributor:  WAM Brokerage Services, L.L.C.
This pages was updated June 12, 2000.

                 If you experience any problems on this page,
             please contact the Webmaster at webmaster@wanger.com