SCHEDULE 13G Amendment No. 4 INTERPUBLIC GROUP OF COS INC Common Stock Cusip #460690100 Cusip #460690100 Item 1: Reporting Person - FMR LLC Item 4: Delaware Item 5: 1,369,144 Item 6: 0 Item 7: 22,235,687 Item 8: 0 Item 9: 22,235,687 Item 11: 4.732% Item 12: HC Cusip #460690100 Item 1: Reporting Person - Edward C. Johnson 3d Item 4: United States of America Item 5: 0 Item 6: 0 Item 7: 22,235,687 Item 8: 0 Item 9: 22,235,687 Item 11: 4.732% Item 12: IN SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b) Item 1(a). Name of Issuer: INTERPUBLIC GROUP OF COS INC Item 1(b). Name of Issuer's Principal Executive Offices: 1114 Avenue of the Americas 19th Floor New York, New York 10036 USA Item 2(a). Name of Person Filing: FMR LLC Item 2(b). Address or Principal Business Office or, if None, Residence: 82 Devonshire Street, Boston, Massachusetts 02109 Item 2(c). Citizenship: Not applicable Item 2(d). Title of Class of Securities: Common Stock Item 2(e). CUSIP Number: 460690100 Item 3. This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b) and the person filing, FMR LLC, is a parent holding company in accordance with Section 240.13d-1(b)(ii)(G). (Note: See Item 7). Item 4. Ownership (a) Amount Beneficially Owned: 22,235,687 (b) Percent of Class: 4.732% (c) Number of shares as to which such person has: (i) sole power to vote or to direct the vote: 1,369,144 (ii) shared power to vote or to direct the vote: 0 (iii) sole power to dispose or to direct the disposition of: 22,235,687 (iv) shared power to dispose or to direct the disposition of: 0 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. See attached Exhibit A. Item 8. Identification and Classification of Members of the Group. Not applicable. See attached Exhibit A. Item 9. Notice of Dissolution of Group. Not applicable. Item 10. Certification. Inasmuch as the reporting persons are no longer the beneficial owners of more than five percent of the number of shares outstanding, the reporting persons have no further reporting obligation under Section 13(d) of the Securities and Exchange Commission thereunder, and the reporting persons have no obligation to amend this Statement if any material change occurs in the facts set forth herein. 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, 2012 Date /s/ Scott C. Goebel Signature Scott C. Goebel Duly authorized under Power of Attorney effective as of June 1, 2008 by and on behalf of FMR LLC and its direct and indirect subsidiaries SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b) Pursuant to the instructions in Item 7 of Schedule 13G, Fidelity Management & Research Company ("Fidelity"), 82 Devonshire Street, Boston, Massachusetts 02109, a wholly- owned subsidiary of FMR LLC and an investment adviser registered under Section 203 of the Investment Advisers Act of 1940, is the beneficial owner of 20,774,969 shares or 4.421% of the Common Stock outstanding of INTERPUBLIC GROUP OF COS INC ("the Company") as a result of acting as investment adviser to various investment companies registered under Section 8 of the Investment Company Act of 1940. The number of shares of Common Stock of INTERPUBLIC GROUP OF COS INC owned by the investment companies at December 31, 2011 included 7,455,721 shares of Common Stock resulting from the assumed conversion of 100,144 shares of INTERPUBLIC GRP 5.25% PC B (74.45 shares of Common Stock for each share of Convertible Preferred Stock). Edward C. Johnson 3d and FMR LLC, through its control of Fidelity, and the funds each has sole power to dispose of the 20,774,969 shares owned by the Funds. Members of the family of Edward C. Johnson 3d, Chairman of FMR LLC, are the predominant owners, directly or through trusts, of Series B voting common shares of FMR LLC, representing 49% of the voting power of FMR LLC. The Johnson family group and all other Series B shareholders have entered into a shareholders' voting agreement under which all Series B voting common shares will be voted in accordance with the majority vote of Series B voting common shares. Accordingly, through their ownership of voting common shares and the execution of the shareholders' voting agreement, members of the Johnson family may be deemed, under the Investment Company Act of 1940, to form a controlling group with respect to FMR LLC. Neither FMR LLC nor Edward C. Johnson 3d, Chairman of FMR LLC, has the sole power to vote or direct the voting of the shares owned directly by the Fidelity Funds, which power resides with the Funds' Boards of Trustees. Fidelity carries out the voting of the shares under written guidelines established by the Funds' Boards of Trustees. Fidelity Management Trust Company, 82 Devonshire Street, Boston, Massachusetts 02109, a wholly-owned subsidiary of FMR LLC and a bank as defined in Section 3(a)(6) of the Securities Exchange Act of 1934, is the beneficial owner of 148,399 shares or 0.032% of the Common Stock outstanding of the Company as a result of its serving as investment manager of the institutional account(s). Edward C. Johnson 3d and FMR LLC, through its control of Fidelity Management Trust Company, each has sole dispositive power over 148,399 shares and sole power to vote or to direct the voting of 148,399 shares of Common Stock owned by the institutional account(s) as reported above. Strategic Advisers, Inc., 82 Devonshire Street, Boston, MA 02109, a wholly-owned subsidiary of FMR LLC and an investment adviser registered under Section 203 of the Investment Advisers Act of 1940, provides investment advisory services to individuals. As such, FMR LLC's beneficial ownership includes 14,624 shares, or 0.003%, of the Common Stock outstanding of INTERPUBLIC GROUP OF COS INC, beneficially owned through Strategic Advisers, Inc. Pyramis Global Advisors, LLC ("PGALLC"), 900 Salem Street, Smithfield, Rhode Island, 02917, an indirect wholly-owned subsidiary of FMR LLC and an investment adviser registered under Section 203 of the Investment Advisers Act of 1940, is the beneficial owner of 1,070,963 shares or 0.228% of the outstanding Common Stock of INTERPUBLIC GROUP OF COS INC as a result of its serving as investment adviser to institutional accounts, non- U.S. mutual funds, or investment companies registered under Section 8 of the Investment Company Act of 1940 owning such shares. The number of shares of Common Stock of INTERPUBLIC GROUP OF COS INC owned by the institutional account(s) at December 31, 2011 included 1,070,963 shares of Common Stock resulting from the assumed conversion of 14,385 shares of INTERPUBLIC GRP 5.25% PC B (74.45 shares of Common Stock for each share of Convertible Preferred Stock). Edward C. Johnson 3d and FMR LLC, through its control of PGALLC, each has sole dispositive power over 1,070,963 shares and sole power to vote or to direct the voting of 1,070,963 shares of Common Stock owned by the institutional accounts or funds advised by PGALLC as reported above. Pyramis Global Advisors Trust Company ("PGATC"), 900 Salem Street, Smithfield, Rhode Island, 02917, an indirect wholly-owned subsidiary of FMR LLC and a bank as defined in Section 3(a)(6) of the Securities Exchange Act of 1934, is the beneficial owner of 226,732 shares or 0.048% of the outstanding Common Stock of the INTERPUBLIC GROUP OF COS INC as a result of its serving as investment manager of institutional accounts owning such shares. The number of shares of Common Stock of INTERPUBLIC GROUP OF COS INC owned by the institutional account(s) at December 31, 2011 included 208,312 shares of Common Stock resulting from the assumed conversion of 2,798 shares of INTERPUBLIC GRP 5.25% PC B (74.45 shares of Common Stock for each share of Convertible Preferred Stock). Edward C. Johnson 3d and FMR LLC, through its control of Pyramis Global Advisors Trust Company, each has sole dispositive power over 226,732 shares and sole power to vote or to direct the voting of 135,158 shares of Common Stock owned by the institutional accounts managed by PGATC as reported above. SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b) RULE 13d-1(f)(1) AGREEMENT The undersigned persons, on February 13, 2012, agree and consent to the joint filing on their behalf of this Schedule 13G in connection with their beneficial ownership of the Common Stock of INTERPUBLIC GROUP OF COS INC at December 31, 2011. FMR LLC By /s/ Scott C. Goebel Scott C. Goebel Duly authorized under Power of Attorney effective as of June 1, 2008, by and on behalf of FMR LLC and its direct and indirect subsidiaries Edward C. Johnson 3d By /s/ Scott C. Goebel Scott C. Goebel Duly authorized under Power of Attorney effective as of June 1, 2008, by and on behalf of Edward C. Johnson 3d Fidelity Management & Research Company By /s/ Scott C. Goebel Scott C. Goebel Senior V.P. and General Counsel