UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. ____ )* Sonus Networks, Inc. - -------------------------------------------------------------------------------- (Name of Issuer) Common Stock - -------------------------------------------------------------------------------- (Title of Class of Securities) 835916107 - -------------------------------------------------------------------------------- (CUSIP Number) December 31, 2005 - -------------------------------------------------------------------------------- (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).
SCHEDULE 13G CUSIP No. 835916107 - ---------------------------------------------------------------------------------------------------------------------------- 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). AMVESCAP PLC INVESCO Asset Management Limited INVESCO Asset Management Ireland Limited INVESCO Institutional (N.A.), Inc. - ---------------------------------------------------------------------------------------------------------------------------- 2. Check the Appropriate Box if a Member of a Group (see Instructions) (a) (b) - ---------------------------------------------------------------------------------------------------------------------------- 3. SEC Use Only _______________________________________________ - ---------------------------------------------------------------------------------------------------------------------------- 4. Citizenship or Place of Organization AMVESCAP PLC: England INVESCO Asset Management Limited: England INVESCO Asset Management Ireland Limited: Ireland INVESCO Institutional (N.A.), Inc.: United States - ---------------------------------------------------------------------------------------------------------------------------- 5. Sole Voting Power 14,102,627: Such shares are held by the following entities in the respective amounts listed: INVESCO Asset Management Limited 13,418,800; INVESCO Asset Management Ireland Limited 437,800; INVESCO Institutional (N.A.), Inc. 246,027; Number of Shares -------------------------------------------------------------------------------------------------- Beneficially Owned by Each Reporting 6. Shared Voting Power ______-0-______ Person With -------------------------------------------------------------------------------------------------- 7. Sole Dispositive Power 14,102,627: Such shares are held by the following entities in the respective amounts listed: INVESCO Asset Management Limited 13,418,800; INVESCO Asset Management Ireland Limited 437,800; INVESCO Institutional (N.A.), Inc. 246,027; -------------------------------------------------------------------------------------------------- 8. Shared Dispositive Power ______-0-______ - ---------------------------------------------------------------------------------------------------------------------------- 9. Aggregate Amount Beneficially Owned by Each Reporting Person 14,102,627 - ---------------------------------------------------------------------------------------------------------------------------- 10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) N/A - ---------------------------------------------------------------------------------------------------------------------------- 11. Percent of Class Represented by Amount in Row (9) 5.66% ---- - ---------------------------------------------------------------------------------------------------------------------------- 12. Type of Reporting Person (See Instructions) IA, HC. See Items 2 and 3 of this statement.
SCHEDULE 13G Item 1(a) Name of Issuer: Sonus Networks, Inc. Item 1(b) Address of Issuer's Principal Executive Offices: 250 Apollo Drive Chelmsford, MA 01824 Item 2(a) Name of Person Filing: AMVESCAP PLC In accordance with Securities and Exchange Commission Release No. 34-39538 (January 12, 1998), this statement on Schedule 13G or amendment thereto is being filed by AMVESCAP PLC ("AMVESCAP"), a U.K. entity, on behalf of itself and its subsidiaries listed in Item 4 of the cover of this statement. AMVESCAP through such subsidiaries provides investment management services to institutional and individual investors worldwide. Executive officers and directors of AMVESCAP or its subsidiaries may beneficially own shares of the securities of the issuer to which this statement relates (the "Shares"), and such Shares are not reported in this statement. AMVESCAP and its subsidiaries disclaim beneficial ownership of Shares beneficially owned by any of their executive officers and directors. Each of AMVESCAP's direct and indirect subsidiaries also disclaim beneficial ownership of Shares beneficially owned by AMVESCAP and any other subsidiary. Item 2(b) Address of Principal Business Office: 30 Finsbury Square London EC2A 1AG England Item 2(c) Citizenship: See the response to Item 2(a) of this statement. Item 2(d) Title of Class of Securities: Common Stock, $.001 par value per share Item 2(e) CUSIP Number: 835916107 Item 3 If this statement is filed pursuant to ss240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: (e) [x] An investment adviser in accordance with section 240.13d-1(b)(1)(ii)(E) (g) [x] A parent holding company or control person in accordance with section 240.13d-1(b)(1)(ii)(G) As noted in Item 2 above, AMVESCAP is making this filing on behalf of its subsidiaries listed herein. Each of these entities is either an investment adviser registered with the United States Securities and Exchange Commission under Section 203 of the Investment Advisers Act of 1940, as amended, or under similar laws of other jurisdictions. AMVESCAP is a holding company.
Item 4 Ownership: Please see responses to Items 5-8 on the cover of this statement, which are incorporated herein by reference. 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 [ ] Item 6 Ownership of More than Five Percent on Behalf of Another Person: N/A Item 7 Identification and Classification of the Subsidiary Which Acquired the Security Being reported on By the Parent Holding Company: Please see Item 3 of this statement, which is incorporated herein by reference. Item 8 Identification and Classification of Members of the Group: N/A Item 9 Notice of Dissolution of a Group: N/A 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. 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. February 13, 2006 -------------------------------------------- Date AMVESCAP PLC By: /s/ Lisa Brinkley -------------------------------------------- Lisa Brinkley Chief Compliance Officer
EXHIBIT A JOINT FILING AGREEMENT ---------------------- In accordance with Rule 13d-1(k)(l) under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree to the joint filing of the attached Schedule 13G, and any and all amendments thereto, and expressly authorize AMVESCAP PLC, as the ultimate parent company of each of its undersigned subsidiaries, to file such Schedule 13G, and any and all amendments thereto, on behalf of each of them. Dated: February 13, 2006 AMVESCAP PLC By: /s/ Lisa Brinkley ---------------------------- Name: Lisa Brinkley Title: Chief Compliance Officer AIM Advisors, Inc. By: /s/ Lisa Brinkley ---------------------------- Name: Lisa Brinkley Title: Chief Compliance Officer AIM Capital Management, Inc. By: /s/ Lisa Brinkley ---------------------------- Name: Lisa Brinkley Title: Chief Compliance Officer AIM Funds Management, Inc. By: /s/ Lisa Brinkley ---------------------------- Name: Lisa Brinkley Title: Chief Compliance Officer AIM Private Asset Management, Inc. By: /s/ Lisa Brinkley ---------------------------- Name: Lisa Brinkley Title: Chief Compliance Officer AMVESCAP National Trust Company By: /s/ Kevin Lyman ---------------------------- Name: Kevin Lyman Title: General Counsel Atlantic Trust Company, N.A. By: /s/ Paul Elmlinger ---------------------------- Name: Paul Elmlinger Title: General Counsel INVESCO Hong Kong Limited By: /s/ Asha Balachandra ---------------------------- Name: Asha Balachandra Title: Reg. Head of Legal AP
INVESCO Asset Management GmbH By: /s/ Stephanie Ehrenfried ---------------------------- Name: Stephanie Ehrenfried Title: Head of Legal CE INVESCO Asset Management Limited By: /s/ Michelle Moran ---------------------------- Name: Michelle Moran Title: Head of Legal for UK and Ireland INVESCO Asset Management S.A. By: /s/ Stephanie Ehrenfried ---------------------------- Name: Stephanie Ehrenfried Title: Head of Legal CE INVESCO Asset Management Osterreich GmbH By: /s/ Stephanie Ehrenfried ---------------------------- Name: Stephanie Ehrenfried Title: Head of Legal CE INVESCO Global Asset Management (N.A.), Inc. By: /s/ Jeffrey Kupor ---------------------------- Name: Jeffrey Kupor Title: General Counsel INVESCO GT Management Company S.A. By: /s/ Nick Styman ---------------------------- Name: Nick Styman Title: Director of European Compliance INVESCO GT Management S.A. By: /s/ Nick Styman ---------------------------- Name: Nick Styman Title: Director of European Compliance INVESCO Institutional (N.A.), Inc. By: /s/ Jeffrey Kupor ---------------------------- Name: Jeffrey Kupor Title: General Counsel INVESCO Italia SGR SpA By: /s/ Stephanie Ehrenfried ---------------------------- Name: Stephanie Ehrenfried Title: Head of Legal CE INVESCO Maximum Income Management S.A. By: /s/ Nick Styman ---------------------------- Name: Nick Styman Title: Director of European Compliance INVESCO Private Capital, Inc. By: /s/ Jeffrey Kupor ---------------------------- Name: Jeffrey Kupor Title: General Counsel INVESCO Senior Secured Management, Inc. By: /s/ Jeffrey Kupor ---------------------------- Name: Jeffrey Kupor Title: General Counsel INVESCO Taiwan Limited By: /s/ Asha Balachandra ---------------------------- Name: Asha Balachandra Title: Reg. Head of Legal, AP INVESCO Asset Management (Japan) Limited By: /s/ Asha Balachandra ---------------------------- Name: Asha Balachandra Title: Reg. Head of Legal, AP INVESCO Asset Management Ireland Limited By: /s/ Michelle Moran ---------------------------- Name: Michelle Moran Title: Head of Legal for UK and Ireland INVESCO Kapitalanlagegesellschaft GmbH By: /s/ Stephanie Ehrenfried ---------------------------- Name: Stephanie Ehrenfried Title: Head of Legal CE Stein Roe Investment Counsel, Inc. By: /s/ Greg Campbell ---------------------------- Name: Greg Campbell Title: General Counsel