PROSPECTUS SUPPLEMENT
(To Prospectus Dated March 6, 1998)
OMNICOM GROUP INC.
$230,000,000 Principal Amount of
2 1/4% Convertible Subordinated Debentures due 2013
(Interest Payable January 6 and July 6)
4,615,694 Shares of Common Stock
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This document supplements the Prospectus dated March 6, 1998 relating to
(i) $230,000,000 aggregate principal amount of 2 1/4% Convertible Subordinated
Debentures due 2013 (the "Debentures") of Omnicom Group Inc., a New York
corporation ("Omnicom" or the "Company"), and (ii) 4,615,694 shares of Common
Stock, par value $0.50 per share (the "Common Stock") of the Company which are
initially issuable upon conversion of the Debentures plus additional
indeterminate number of shares of Common Stock as may become issuable upon
conversion of the Debentures as a result of adjustments to the conversion price
(the "Shares"). The Debentures were initially acquired from the Company by
Morgan Stanley & Co. Incorporated in January 1998 in connection with a private
offering. This Prospectus Supplement is incorporated by reference into the
Prospectus, and all terms used herein shall have the meaning assigned to them in
the Prospectus. On May 8, 1998 the closing price of the Common Stock as reported
on the New York Stock Exchange was $48.3125 per share. The Common Stock is
traded under the symbol "OMC".
In accordance with the Section of the Prospectus entitled "Selling
Securityholders" (which appears on page 19 of the Prospectus), the following
information is provided with respect to the beneficial owners of the Debentures:
<TABLE>
<CAPTION>
Principal Amount of Principal Amount of
Debentures Beneficially Debentures to be
Name of Selling Shareholder(s) Owned Offered for Sale
------------------------------ ---------------------- -------------------
<S> <C> <C>
City of Birmingham Retirement & Relief System 2,100,000 2,100,000
Merrill Lynch Insurance Group 300,000 300,000
Morgan Stanley Dean Witter 16,175,000 16,175,000
Occidental Petroleum 50,000 50,000
Toronto Dominion (New York), Inc. 5,000,000 5,000,000
TQA Arbitrage Fund, L.P. 1,000,000 1,000,000
</TABLE>
The Debentures being offered by the Selling Securityholders hereby
represent all of the Debentures beneficially owned by the Selling
Securityholders as of May 8, 1998. Except for Morgan Stanley's position as the
Initial Purchaser of the Debentures and as the initial purchaser of the
Company's 4 1/4% Convertible Subordinated Debentures due 2007 issued on January
3, 1997, and except for the purchase of the Debentures, none of the Selling
Securityholders has had a material relationship with the Company or any of its
affiliates within the past three years.
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THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES
AND EXCHANGE COMMISSION OR ANY STATE SECURITY COMMISSION NOR HAS THE SECURITIES
AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.
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The date of this Prospectus Supplement is May 12, 1998.
