SC 13G/A 1 dsc13ga.txt SCHEDULE 13G AMENDMENT NO 1 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1 )* Vitalstream Holdings, Inc. -------------------------------------------------------------------------------- (Name of Issuer) Common Stock -------------------------------------------------------------------------------- (Title of Class of Securities) 92847T100 --------------------------------------------- (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). CUSIP NO. 92847T100 13G Page 2 of 6 Pages --------- -------------------------------------------------------------------------------- 1. Names of Reporting Persons. I.R.S. Identification Nos. of Above Persons (entities only). Columbia Acorn Trust -------------------------------------------------------------------------------- 2. Check the Appropriate Box If a Member of a Group (See Instructions) (a) [_] Not Applicable (b) [_] -------------------------------------------------------------------------------- 3. SEC Use Only -------------------------------------------------------------------------------- 4. Citizenship or Place of Organization Massachusetts -------------------------------------------------------------------------------- 5. Sole Voting Power NUMBER OF None SHARES ------------------------------------------------------------- BENEFICIALLY 6. Shared Voting Power OWNED BY EACH 1,051,030 REPORTING ------------------------------------------------------------- PERSON 7. Sole Dispositive Power WITH None ------------------------------------------------------------- 8. Shared Dispositive Power 1,051,030 -------------------------------------------------------------------------------- 9. Aggregate Amount Beneficially Owned by Each Reporting Person 1,051,030 -------------------------------------------------------------------------------- 10. Check Box If the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) Not Applicable [_] -------------------------------------------------------------------------------- 11. Percent of Class Represented by Amount in Row (9) 3.4% -------------------------------------------------------------------------------- 12. Type of Reporting Person (See Instructions) IV -------------------------------------------------------------------------------- Item 1(a) Name of Issuer: Vitalstream Holdings, Inc. Item 1(b) Address of Issuer's Principal Executive Offices: One Jenner, Suite 100, Irvine, CA 92618 Item 2(a) Name of Person Filing: Columbia Acorn Trust ("Acorn") Item 2(b) Address of Principal Business Office: Acorn is located at: 227 West Monroe Street, Suite 3000 Chicago, Illinois 60606 Item 2(c) Citizenship: Acorn is a Massachusetts business trust. Item 2(d) Title of Class of Securities: Common Stock Item 2(e) CUSIP Number: 92847T100 Item 3 Type of Person: (d) Acorn is an Investment Company under section 8 of the Investment Company Act. Page 3 of 6 pages Item 4 Ownership (at December 31, 2003): (a) Amount owned "beneficially" within the meaning of rule 13d-3: 1,051,030 (b) Percent of class: 3.4% (based on 31,258,392 shares outstanding as of November 13, 2003 based on Form 10-Q filed on November 14, 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: 1,051,030 (iii) sole power to dispose or to direct the disposition of: none (iv) shared power to dispose or to direct disposition of: 1,051,030 Item 5 Ownership of Five Percent or Less of a Class: If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following [X]. Item 6 Ownership of More than Five Percent on Behalf of Another Person: Not Applicable 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 4 of 6 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 5 of 6 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 12, 2004 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 6 of 6 Pages