EX-99.77B ACCT LTTR

            REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Trustees and Shareholders of Columbia Acorn Trust:

In planning and performing our audit of the financial statements of Columbia
Acorn Fund, Columbia Acorn International, Columbia Acorn USA, Columbia Acorn
International Select, Columbia Acorn Select, Columbia Thermostat Fund, Columbia
Acorn Emerging Markets Fund, and Columbia Acorn European Fund (the "Funds") as
of and for the year or period ended December 31, 2011, in accordance with the
standards of the Public Company Accounting Oversight Board (United States), we
considered the Funds' internal control over financial reporting, including
controls over safeguarding securities, as a basis for designing our auditing
procedures for the purpose of expressing our opinion on the financial
statements and to comply with the requirements of Form N-SAR, but not for the
purpose of expressing an opinion on the effectiveness of the Funds' internal
control over financial reporting. Accordingly, we do not express an opinion on
the effectiveness of the Funds' internal control over financial reporting.

The management of the Funds is responsible for establishing and maintaining
effective internal control over financial reporting. In fulfilling this
responsibility, estimates and judgments by management are required to assess
the expected benefits and related costs of controls. A fund's internal control
over financial reporting is a process designed to provide reasonable assurance
regarding the reliability of financial reporting and the preparation of
financial statements for external purposes in accordance with generally
accepted accounting principles. A fund's internal control over financial
reporting includes those policies and procedures that (1) pertain to the
maintenance of records that, in reasonable detail, accurately and fairly
reflect the transactions and dispositions of the assets of the fund;
(2) provide reasonable assurance that transactions are recorded as necessary to
permit preparation of financial statements in accordance with generally
accepted accounting principles, and that receipts and expenditures of the Fund
are being made only in accordance with authorizations of management and
trustees of the fund; and (3) provide reasonable assurance regarding prevention
or timely detection of unauthorized acquisition, use or disposition of a fund's
assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting
may not prevent or detect misstatements. Also, projections of any evaluation of
effectiveness to future periods are subject to the risk that controls may
become inadequate because of changes in conditions, or that the degree of
compliance with the policies or procedures may deteriorate.

A deficiency in internal control over financial reporting exists when the
design or operation of a control does not allow management or employees, in the
normal course of performing their assigned functions, to prevent or detect
misstatements on a timely basis. A material weakness is a deficiency, or a
combination of deficiencies, in internal control over financial reporting, such
that there is a reasonable possibility that a material misstatement of the
Funds' annual or interim financial statements will not be prevented or detected
on a timely basis.

Our consideration of the Funds' internal control over financial reporting was
for the limited purpose described in the first paragraph and would not
necessarily disclose all deficiencies in internal control over financial
reporting that might be material weaknesses under standards established by the
Public Company Accounting Oversight Board (United States). However, we noted no
deficiencies in the Funds' internal control over financial reporting and its
operation, including controls over safeguarding securities that we consider to
be material weaknesses as defined above as of December 31, 2011.

This report is intended solely for the information and use of management and
the Board of Trustees of the Funds and the Securities and Exchange Commission
and is not intended to be and should not be used by anyone other than these
specified parties.

/s/ PricewaterhouseCoopers LLP

Chicago, Illinois
February 17, 2012

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PricewaterhouseCoopers LLP, One North Wacker Drive Chicago, IL 60606
T: (312) 298 2000, F: (312) 298 2001, www.pwc.com/us

EX-99.77D POLICIES

                                                                    Exhibit 77D

COLUMBIA ACORN TRUST (THE "TRUST")--ANNUAL N-SAR REPORT FOR THE PERIOD ENDING
12/31/11

Columbia Acorn Fund
Columbia Acorn International
Columbia Acorn USA
Columbia Acorn Select
Columbia Acorn International Select
Columbia Thermostat Fund
Columbia Acorn European Fund
Columbia Acorn Emerging Markets Fund
(the "Funds")

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ITEM 77D/77Q1(B)--POLICIES WITH RESPECT TO SECURITIES INVESTMENTS:

On December 12, 2011, Form Type 497, ACCESSION NO. 0001193125-11-337544, a
supplement to the registration statement of Columbia Acorn Trust on behalf of
Columbia Thermostat Fund was filed with the SEC. It is hereby incorporated by
reference as part of the response to these Items 77D and 77Q1(b) of Form N-SAR.
The supplement disclosed, among other things, changes to the allocation of
underlying funds in the principal investment strategy of Columbia Thermostat
Fund.

EX-99.77E LEGAL

                                                                    EXHIBIT 77E

ITEM 77E--LEGAL PROCEEDINGS:

In June 2004, an action captioned John E. Gallus et al. v. American Express
Financial Corp. and American Express Financial Advisors Inc. was filed in the
United States District Court for the District of Arizona. The plaintiffs allege
that they are investors in several American Express Company mutual funds
(branded as Columbia) and they purport to bring the action derivatively on
behalf of those funds under the Investment Company Act of 1940. The plaintiffs
allege that fees allegedly paid to the defendants by the funds for investment
advisory and administrative services are excessive. The plaintiffs seek
remedies including restitution and rescission of investment advisory and
distribution agreements. The plaintiffs voluntarily agreed to transfer this
case to the United States District Court for the District of Minnesota (the
District Court). In response to defendants' motion to dismiss the complaint,
the District Court dismissed one of plaintiffs' four claims and granted
plaintiffs limited discovery. Defendants moved for summary judgment in April
2007. Summary judgment was granted in the defendants' favor on July 9, 2007.
The plaintiffs filed a notice of appeal with the Eighth Circuit Court of
Appeals (the Eighth Circuit) on August 8, 2007. On April 8, 2009, the Eighth
Circuit reversed summary judgment and remanded to the District Court for
further proceedings. On August 6, 2009, defendants filed a writ of certiorari
with the U.S. Supreme Court (the Supreme Court), asking the Supreme Court to
stay the District Court proceedings while the Supreme Court considers and rules
in a case captioned Jones v. Harris Associates, which involves issues of law
similar to those presented in the Gallus case. On March 30, 2010, the Supreme
Court issued its ruling in Jones v. Harris Associates, and on April 5, 2010,
the Supreme Court vacated the Eighth Circuit's decision in the Gallus case and
remanded the case to the Eighth Circuit for further consideration in light of
the Supreme Court's decision in Jones v. Harris Associates. On June 4, 2010,
the Eighth Circuit



remanded the Gallus case to the District Court for further consideration in
light of the Supreme Court's decision in Jones v. Harris Associates. On
December 9, 2010, the District Court reinstated its July 9, 2007 summary
judgment order in favor of the defendants. On January 10, 2011, plaintiffs
filed a notice of appeal with the Eighth Circuit. In response to the
plaintiffs' opening appellate brief filed on March 18, 2011, the defendants
filed a response brief on May 4, 2011 with the Eighth Circuit. The plaintiffs
filed a reply brief on May 26, 2011 and oral arguments took place on
November 17, 2011.

In December 2005, without admitting or denying the allegations, American
Express Financial Corporation (AEFC, which is now known as Ameriprise
Financial, Inc. (Ameriprise Financial)), entered into settlement agreements
with the Securities and Exchange Commission (SEC) and Minnesota Department of
Commerce (MDOC) related to market timing activities. As a result, AEFC was
censured and ordered to cease and desist from committing or causing any
violations of certain provisions of the Investment Advisers Act of 1940, the
Investment Company Act of 1940, and various Minnesota laws. AEFC agreed to pay
disgorgement of $10 million and civil money penalties of $7 million. AEFC also
agreed to retain an independent distribution consultant to assist in developing
a plan for distribution of all disgorgement and civil penalties ordered by the
SEC in accordance with various undertakings detailed at
www.sec.gov/litigation/admin/ia-2451.pdf. Ameriprise Financial and its
affiliates have cooperated with the SEC and the MDOC in these legal
proceedings, and have made regular reports to the funds' Boards of Trustees.

Ameriprise Financial and certain of its affiliates have historically been
involved in a number of legal, arbitration and regulatory proceedings,
including routine litigation, class actions, and governmental actions,
concerning matters arising in connection with the conduct of their business
activities. Ameriprise Financial believes that the Funds are not currently the
subject of, and that neither Ameriprise Financial nor any of its affiliates are
the subject of, any pending legal, arbitration or regulatory proceedings that
are likely to have a material adverse effect on the Funds or the ability of
Ameriprise Financial or its affiliates to perform under their contracts with
the Funds. Ameriprise Financial is required to make 10-Q, 10-K and, as
necessary, 8-K filings with the Securities and Exchange Commission on legal and
regulatory matters that relate to Ameriprise Financial and its affiliates.
Copies of these filings may be obtained by accessing the SEC website at
www.sec.gov.

There can be no assurance that these matters, or the adverse publicity
associated with them, will not result in increased fund redemptions, reduced
sale of fund shares or other adverse consequences to the Funds. Further,
although we believe proceedings are not likely to have a material adverse
effect on the Funds or the ability of Ameriprise Financial or its affiliates to
perform under their contracts with the Funds, these proceedings are subject to
uncertainties and, as such, we are unable to estimate the possible loss or
range of loss that may result. An adverse outcome in one or more of these
proceedings could result in adverse judgments, settlements, fines, penalties or
other relief that could have a material adverse effect on the consolidated
financial condition or results of operations of Ameriprise Financial.

EX-99.77M MERGERS

                                                                    Exhibit 77M

ITEM 77M/77Q1(G) - MERGERS:

The series of Columbia Acorn Trust listed in the table below in the column
captioned "Acquiring Fund" (the "Acquiring Fund") became the surviving entity
in a reorganization (the "Reorganization") with the two series of RiverSource
International Managers Series, Inc. listed next to it under the column of the
table below captioned "Acquired Fund" (the "Acquired Fund"):



                   ACQUIRED FUNDS                             ACQUIRING FUND
                   --------------                             --------------
                                                    
RiverSource Partners International Select Growth Fund  Columbia Acorn International
RiverSource Partners International Small Cap Fund


In November 2010, the Board of Directors of RiverSource International Managers
Series, Inc. and in May 11, 2011, the Board of Trustees of Columbia Acorn Trust
each approved an agreement and plan of reorganization (the "Agreement and
Plan") providing for the sale of all of the assets of the Acquired Funds to,
and the assumption of all of the liabilities and obligations of the Acquired
Funds by, the Acquiring Fund, in complete liquidation of the Acquired Funds. At
a special meeting of shareholders held on April 27, 2011, shareholders of
RiverSource Partners International Small Cap Fund and shareholders of
RiverSource Partners International Select Growth Fund approved the Agreement
and Plan with respect to the Reorganization.

Effective on August 12, 2011, the Acquiring Fund acquired all the assets of,
and assumed all the liabilities and obligations of the Acquired Funds in
complete liquidation of the Acquired Funds. Shareholders of each class of
shares of the Acquired Funds received shares of the corresponding share class
of the Acquiring Fund in accordance with the Agreement and Plan.

The registration statement of Columbia Acorn Trust on behalf of Columbia Acorn
International, on Form N-14, which was filed with the Securities and Exchange
Commission on November 16, 2010 (ACCESSION NO. 0001193125-10-261888) is
incorporated by reference, including without limitation the Agreement and Plan
filed as Exhibit (4) to the registration statement and the applicable
prospectus/proxy statement describing the applicable Reorganization.