-----BEGIN PRIVACY-ENHANCED MESSAGE----- Proc-Type: 2001,MIC-CLEAR Originator-Name: webmaster@www.sec.gov Originator-Key-Asymmetric: MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB MIC-Info: RSA-MD5,RSA, VEec8t9pLXiQAcUShcwc/4jd7IvV5XHttIh9XgmiAZicnjpmYkqeVP0pjRWJKNgb HQ9K6C/rT5Z6EzOeSm2dZQ== 0000950131-01-001053.txt : 20010223 0000950131-01-001053.hdr.sgml : 20010223 ACCESSION NUMBER: 0000950131-01-001053 CONFORMED SUBMISSION TYPE: SC 13G PUBLIC DOCUMENT COUNT: 1 FILED AS OF DATE: 20010214 SUBJECT COMPANY: COMPANY DATA: COMPANY CONFORMED NAME: AMERICAN DENTAL PARTNERS INC CENTRAL INDEX KEY: 0001028087 STANDARD INDUSTRIAL CLASSIFICATION: SERVICES-MISC HEALTH & ALLIED SERVICES, NEC [8090] IRS NUMBER: 043297858 STATE OF INCORPORATION: DE FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SC 13G SEC ACT: SEC FILE NUMBER: 005-55325 FILM NUMBER: 1541222 BUSINESS ADDRESS: STREET 1: 301 EDGEWATER PLACE STREET 2: SUITE 320 CITY: WAKEFIELD STATE: MA ZIP: 01880-1249 BUSINESS PHONE: 6172240880 MAIL ADDRESS: STREET 1: 301 EDGEWATER PLACE STREET 2: SUITE 320 CITY: WAKEFIELD STATE: MA ZIP: 01880 FILED BY: COMPANY DATA: COMPANY CONFORMED NAME: WANGER ASSET MANAGEMENT LP CENTRAL INDEX KEY: 0000908733 STANDARD INDUSTRIAL CLASSIFICATION: UNKNOWN SIC - 0000 [0000] IRS NUMBER: 363820584 STATE OF INCORPORATION: DE FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SC 13G BUSINESS ADDRESS: STREET 1: 227 W MONROE STREET STREET 2: SUITE 3000 CITY: CHICAGO STATE: IL ZIP: 60606 BUSINESS PHONE: 3126349230 MAIL ADDRESS: STREET 1: 227 W MONROE ST STREET 2: STE 3000 CITY: CHICAGO STATE: IL ZIP: 60606 FORMER COMPANY: FORMER CONFORMED NAME: WANGER ASSET MANAGEMENT LP DATE OF NAME CHANGE: 19960619 SC 13G 1 0001.txt SCHEDULE 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. ________)* AMERICAN DENTAL PARTNERS, INC. (Name of Issuer) Common Stock - -------------------------------------------------------------------------------- (Title of Class of Securities) 25353103 ----------------------------------- CUSIP Number) December 31, 2000 ------------------------------------------------- (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 9 pages - ------------------------------- -------------------------------- CUSIP No. 25353103 13G Page 2 of 9 Pages - ------------------------------- -------------------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1 S.S OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Liberty Wanger Asset Management, L.P. 36-3820584 - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* 2 (a) [_] (b) [_] Not Applicable - ------------------------------------------------------------------------------ SEC USE ONLY 3 - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4 Delaware - ------------------------------------------------------------------------------ SOLE VOTING POWER 5 NUMBER OF None SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6 OWNED BY 409,000 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7 REPORTING None PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8 409,000 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9 409,000 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* 10 [_] Not Applicable - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 11 5.7% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON* 12 IA - ------------------------------------------------------------------------------ *SEE INSTRUCTION BEFORE FILLING OUT! - ------------------------------- -------------------------------- CUSIP No. 25353103 13G Page 3 of 9 Pages - ------------------------------- -------------------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1 S.S OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON WAM Acquisition GP, Inc. - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* 2 (a) [_] (b) [_] Not Applicable - ------------------------------------------------------------------------------ SEC USE ONLY 3 - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4 Delaware - ------------------------------------------------------------------------------ SOLE VOTING POWER 5 NUMBER OF None SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6 OWNED BY 409,000 ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7 REPORTING None PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8 409,000 - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9 409,000 - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* 10 [_] Not Applicable - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 11 5.7% - ------------------------------------------------------------------------------ TYPE OF REPORTING PERSON* 12 CO - ------------------------------------------------------------------------------ *SEE INSTRUCTION BEFORE FILLING OUT! Item 1(a) Name of Issuer: American Dental Partners, Inc. Item 1(b) Address of Issuer's Principal Executive Offices: 301 Edgewater Place, Suite 320 Wakefield, MA 01880 Item 2(a) Name of Person Filing: Liberty Wanger Asset Management, L.P. ("WAM") WAM Acquisition GP, Inc., the general partner of WAM ("WAM GP") Item 2(b) Address of Principal Business Office: WAM and WAM GP are located at: 227 West Monroe Street, Suite 3000 Chicago, Illinois 60606 Item 2(c) Citizenship: WAM is a Delaware limited partnership; and WAM GP is a Delaware corporation. Item 2(d) Title of Class of Securities: Common Stock Item 2(e) CUSIP Number: 25353103 Item 3 Type of Person: (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 4 of 9 pages Item 4 Ownership (at December 31, 2000): (a) Amount owned "beneficially" within the meaning of rule 13d-3: 409,000 (b) Percent of class: 5.7% (based on 7,130,532 shares outstanding as of November 10, 2000) (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: 409,000 (iii) sole power to dispose or to direct the disposition of: none (iv) shared power to dispose or to direct disposition of: 409,000 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. Persons other than WAM and WAM GP are entitled to receive all dividends from, and proceeds from the sale of, those shares. 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 5 of 9 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 6 of 9 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 14, 2001 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 LIBERTY WANGER ASSET MANAGEMENT, L.P. By: /s/ Bruce H. Lauer ------------------------------------------ Bruce H. Lauer Senior Vice President and Secretary Page 7 of 9 Pages Exhibit Index ------------- Exhibit 1 Joint Filing Agreement dated as of February 14, 2001 by and among Liberty Wanger Asset Management, L.P. and WAM Acquisition GP, Inc. Page 8 of 9 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 14, 2001 WAM Acquisition GP, Inc. for itself and as general partner of LIBERTY WANGER ASSET MANAGEMENT, L.P. By: /s/ Bruce H. Lauer ------------------------------------------ Bruce H. Lauer Senior Vice President and Secretary Page 9 of 9 pages -----END PRIVACY-ENHANCED MESSAGE-----