Prospectus Supplement filed under Rule 424(b)(3) Registration No. 333-45569 Prospectus Supplement The Prospectus dated February 4, 1998 relating to the offer for resale of up to $250,000,000 aggregate principal amount of The Interpublic Group of Companies, Inc.'s 1.80% Convertible Subordinated Notes due September 16, 2004 is hereby supplemented to include the following information in the "Selling Security- holders" table in the Prospectus Supplement dated February 25, 1998: Principal Amount of Registered Selling Holders Notes - ------------------------------------------------- ---------------- Pell Rudman Trust Co. NA......................... $1,150,000 Merrill, Lynch, Pierce, Fenner and Smith, Inc.... 850,000 - ------------------------------------------------- ---------------- Total of Above................................... $2,000,000 ================ This Prospectus Supplement is dated September 10, 1998.