UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                  SCHEDULE 13G


                    Under the Securities Exchange Act of 1934

                             (Amendment No.   1  )*
                                            -----

                               Actuate Corporation
--------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    00508B102
                  ---------------------------------------------
                                 (CUSIP Number)

                                December 31, 2003
         --------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)

     Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:

                                [x] Rule 13d-1(b)
                                [_] Rule 13d-1(c)
                                [_] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).

                               Page 1 of 10 pages



------------------------                                   ---------------------
CUSIP No. 00508B102                    13G                 Page 2 of 10 Pages
          ------------
------------------------                                   ---------------------

--------------------------------------------------------------------------------
  1    NAME OF REPORTING PERSON
       S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

           Columbia Wanger Asset Management, L.P.  36-3820584
--------------------------------------------------------------------------------
  2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

           Not Applicable                                                (a) [_]

                                                                         (b) [_]
--------------------------------------------------------------------------------
  3    SEC USE ONLY


--------------------------------------------------------------------------------
  4    CITIZENSHIP OR PLACE OF ORGANIZATION

           Delaware
--------------------------------------------------------------------------------
     NUMBER OF         5    SOLE VOTING POWER

       SHARES                   None
                       ---------------------------------------------------------
    BENEFICIALLY       6    SHARED VOTING POWER

      OWNED BY                  7,206,500
                       ---------------------------------------------------------
        EACH           7    SOLE DISPOSITIVE POWER

     REPORTING                  None
                       ---------------------------------------------------------
    PERSON WITH        8    SHARED DISPOSITIVE POWER

                                7,206,500
--------------------------------------------------------------------------------
  9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            7,206,500
--------------------------------------------------------------------------------
  10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

           Not Applicable                                                    [_]
--------------------------------------------------------------------------------
  11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

           11.7%
--------------------------------------------------------------------------------
  12   TYPE OF REPORTING PERSON*

           IA
--------------------------------------------------------------------------------



------------------------                                   ---------------------
CUSIP No. 00508B102                    13G                 Page 3 of 10 Pages
          ------------
------------------------                                   ---------------------

--------------------------------------------------------------------------------
  1    NAME OF REPORTING PERSON
       S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

           WAM Acquisition GP, Inc.
--------------------------------------------------------------------------------
  2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

           Not Applicable                                                (a) [_]

                                                                         (b) [_]
--------------------------------------------------------------------------------
  3    SEC USE ONLY


--------------------------------------------------------------------------------
  4    CITIZENSHIP OR PLACE OF ORGANIZATION

           Delaware
--------------------------------------------------------------------------------
     NUMBER OF         5    SOLE VOTING POWER

       SHARES                   None
                       ---------------------------------------------------------
    BENEFICIALLY       6    SHARED VOTING POWER

      OWNED BY                  7,206,500
                       ---------------------------------------------------------
        EACH           7    SOLE DISPOSITIVE POWER

     REPORTING                  None
                       ---------------------------------------------------------
    PERSON WITH        8    SHARED DISPOSITIVE POWER

                                7,206,500
--------------------------------------------------------------------------------
  9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            7,206,500

--------------------------------------------------------------------------------
  10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

           Not Applicable                                                    [_]
--------------------------------------------------------------------------------
  11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

           11.7%
--------------------------------------------------------------------------------
  12   TYPE OF REPORTING PERSON*

           CO
--------------------------------------------------------------------------------



------------------------                                   ---------------------
CUSIP No. 00508B102                    13G                 Page 4 of 10 Pages
          ------------
------------------------                                   ---------------------

--------------------------------------------------------------------------------
  1    NAME OF REPORTING PERSON
       S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

           Columbia Acorn Trust
--------------------------------------------------------------------------------
  2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

           Not Applicable                                                (a) [_]

                                                                         (b) [_]
--------------------------------------------------------------------------------
  3    SEC USE ONLY


--------------------------------------------------------------------------------
  4    CITIZENSHIP OR PLACE OF ORGANIZATION

           Massachusetts
--------------------------------------------------------------------------------
     NUMBER OF         5    SOLE VOTING POWER

       SHARES                   None
                       ---------------------------------------------------------
    BENEFICIALLY       6    SHARED VOTING POWER

      OWNED BY                  6,000,000
                       ---------------------------------------------------------
        EACH           7    SOLE DISPOSITIVE POWER

     REPORTING                  None
                       ---------------------------------------------------------
    PERSON WITH        8    SHARED DISPOSITIVE POWER

                                6,000,000
--------------------------------------------------------------------------------
  9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            6,000,000
--------------------------------------------------------------------------------
  10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

           Not Applicable                                                    [_]
--------------------------------------------------------------------------------
  11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

           9.8%
--------------------------------------------------------------------------------
  12   TYPE OF REPORTING PERSON*

           IV
--------------------------------------------------------------------------------



Item 1(a)         Name of Issuer:

                      Actuate Corporation

Item 1(b)         Address of Issuer's Principal Executive Offices:

                      701 Gateway Boulevard
                      South San Francisco, California 94080


Item 2(a)         Name of Person Filing:

                      Columbia Wanger Asset Management, L.P. ("WAM")
                      WAM Acquisition GP, Inc., the general partner of WAM
                        ("WAM GP")
                      Columbia Acorn Trust ("Acorn")

Item 2(b)         Address of Principal Business Office:

                      WAM, WAM GP and Acorn are all located at:

                      227 West Monroe Street, Suite 3000
                      Chicago, Illinois 60606

Item 2(c)         Citizenship:

                      WAM is a Delaware limited partnership; WAM GP is a
                      Delaware corporation; and Acorn is a Massachusetts
                      business trust.

Item 2(d)         Title of Class of Securities:

                      Common Stock

Item 2(e)         CUSIP Number:

                      00508B102

Item 3            Type of Person:

                      (d)   Acorn is an Investment Company under section 8 of
                            the Investment Company Act.

                      (e)   WAM is an Investment Adviser registered under
                            section 203 of the Investment Advisers Act of 1940;
                            WAM GP is the General Partner of the Investment
                            Adviser.

                               Page 5 of 10 pages



Item 4     Ownership (at December 31, 2003):

                   (a) Amount owned "beneficially" within the meaning of rule
                       13d-3:

                       7,206,500

                   (b) Percent of class:
                       11.7% (based on 61,420,525 shares outstanding as of
                       September 30, 2003).

                   (c) Number of shares as to which such person has:

                            (i)   sole power to vote or to direct the vote: none

                            (ii)  shared power to vote or to direct the vote:
                                  7,206,500

                            (iii) sole power to dispose or to direct the
                                  disposition of: none

                            (iv)  shared power to dispose or to direct
                                  disposition of: 7,206,500

Item 5     Ownership of Five Percent or Less of a Class:

                   Not Applicable

Item 6     Ownership of More than Five Percent on Behalf of Another Person:

                   The shares reported herein have been acquired on behalf of
                   discretionary clients of WAM, including Acorn. Persons other
                   than WAM and WAM GP are entitled to receive all dividends
                   from, and proceeds from the sale of, those shares. Acorn is
                   the only such person known to be entitled to all dividends
                   from, and all proceeds from the sale of, shares reported
                   herein to the extent of more than 5% of the class.

Item 7     Identification and Classification of the Subsidiary Which Acquired
           the Security Being Reported on by the Parent Holding Company:

                   Not Applicable

Item 8     Identification and Classification of Members of the Group:

                   Not Applicable

Item 9     Notice of Dissolution of Group:

                   Not Applicable

                               Page 6 of 10 pages



Item 10    Certification:

               By signing below I certify that, to the best of my knowledge and
           belief, the securities referred to above were acquired and are held
           in the ordinary course of business and were not acquired and are not
           held for the purpose of or with the effect of changing or influencing
           the control of the issuer of the securities and were not acquired and
           are not held in connection with or as a participant in any
           transaction having that purpose or effect.

                               Page 7 of 10 Pages



                                    Signature

         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

Date:  February 13, 2004

                  The undersigned corporation, on the date above written, agrees
                  and consents to the joint filing on its behalf of this
                  Schedule 13G in connection with its beneficial ownership of
                  the security reported herein.

                                     WAM Acquisition GP, Inc.
                                         for itself and as general partner of
                                         COLUMBIA WANGER ASSET MANAGEMENT, L.P.



                                     By: /s/ Bruce H. Lauer
                                         ----------------------------------
                                             Bruce H. Lauer
                                             Senior Vice President and Secretary

                  The undersigned trust, on the date above written, agrees and
                  consents to the joint filing on its behalf of this Schedule
                  13G in connection with its beneficial ownership of the
                  security reported herein.

                                     COLUMBIA ACORN TRUST

                                     By: /s/ Bruce H. Lauer
                                         ----------------------------------
                                             Bruce H. Lauer
                                             Vice President, Treasurer and
                                             Secretary

                               Page 8 of 10 Pages



                                  Exhibit Index

Exhibit 1          Joint Filing Agreement dated as of February 13, 2004 by and
                   among Columbia Wanger Asset Management, L.P., WAM Acquisition
                   GP, Inc. and Columbia Acorn Trust.

                               Page 9 of 10 Pages



                                                                       EXHIBIT 1

                             JOINT FILING AGREEMENT

         The undersigned hereby agree to the joint filing of the Schedule 13G to
which this Agreement is attached.

                       Dated: February 13, 2004

                                  WAM Acquisition GP, Inc.
                                      for itself and as general partner of
                                      COLUMBIA WANGER ASSET MANAGEMENT, L.P.



                                  By: /s/ Bruce H. Lauer
                                      ------------------------------------------
                                          Bruce H. Lauer
                                          Senior Vice President and Secretary

                                  COLUMBIA ACORN TRUST

                                  By: /s/ Bruce H. Lauer
                                      ------------------------------------------
                                          Bruce H. Lauer
                                          Vice President, Treasurer and
                                          Secretary

                              Page 10 of 10 pages