THE INTERPUBLIC GROUP OF COMPANIES, INC. and THE BANK OF NEW YORK Trustee __________________________ Sixth Supplemental Indenture Dated as of March 30, 2005 to the Senior Debt Indenture dated as of October 20, 2000, as amended and supplemented by the Third Supplemental Indenture dated as of March 13, 2003 ____________________________

“Covenant Reversion Date” means the earliest of 5:30 p.m., New York City time, on (i) the Business Day following the Company’s failure to pay the Initial Consent Fee, if due, for the Notes in accordance with the Solicitation Documents, (ii) the Business Day following the Company’s failure to pay the Additional Consent Fee, if due, for the Notes in accordance with the Solicitation Documents and (iii) September 30, 2005.

“Effective Date” has the meaning provided in Section 2.08(12).

“Initial Consent Fee” means $2.50 for each $1,000 in principal amount of the Notes as to which the Company has received and accepted consents to the Amendments, as may be payable to holders of record as of March 9, 2005 in accordance with the Solicitation Documents.

“SEC Reports” means the Company’s Annual Report on Form 10-K for the year ended December 31, 2004 and Quarterly Reports on Form 10-Q for the three months ended March 31, 2005 and June 30, 2005, respectively, and other information, documents and reports which the Company may be required to file with the Commission pursuant to Section 13 or 15(d) of the Exchange Act.

“Solicitation Documents” means the Consent Solicitation Statement dated as of March 18, 2005, as supplemented by a supplement dated March 30, 2005, and the related Consent Form, each as may be amended and supplemented from time to time.

“Stock Price” has the meaning provided in Section 2.08(12).

  ARTICLE 3

AMENDMENT TO ARTICLE 2 OF THE INDENTURE

SECTION 3.01. Amendments to Section 2.02 of the Third Supplemental Indenture. Section 2.02 of the Third Supplemental Indenture is hereby amended by inserting the following as the final sentence of Section 2.02(1):

“Notwithstanding the foregoing or any provisions of paragraph 6 of the Notes to the contrary, the Notes are not redeemable prior to September 15, 2009.”

SECTION 3.02. Amendments to Section 2.08 of the Third Supplemental Indenture. Section 2.08 of the Third Supplemental Indenture is hereby amended by inserting the following terms as Section 2.08(12):

“(12).       Adjustment for Conversion Upon a Cash Take-Over Transaction. If a Holder elects to convert Notes, pursuant to the satisfaction of the conditions described in clause (e) of paragraph 10 in the Notes in connection with a Fundamental Change referred to in clause (b) of the definition of Fundamental Change contained in Section 1.01 pursuant to which 10% or more of the consideration for the Common Stock (excluding cash payments for fractional shares and cash payments made in respect of dissenters’ appraisal rights) in the transaction or transactions otherwise constituting the Fundamental Change does not consist of Publicly Traded Securities (a “Cash Take-Over Transaction”), the Company will increase the number of shares of Common Stock issuable upon conversion of the Notes by a number of additional shares of Common Stock (the “Additional Common Stock”) as set forth below. The number of shares of Additional Common Stock shall be determined by reference to the table below, based on the date on which the Cash Take-Over Transaction becomes effective (the “Effective Date”) and the price (the “Stock Price”) paid per share for the Common Stock in the Cash Take-Over Transaction. If holders of Common Stock receive only cash in the Cash Take-Over Transaction, the Stock Price shall be the cash amount paid per share. Otherwise, the Stock Price shall be the average of the Sale Price of the Common Stock on the five Trading Days prior to but not including the Effective Date.