Sec Form 4 Filing - WREN JOHN @ OMNICOM GROUP INC. - 2021-04-23

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person WREN JOHN 2. Issuer Name and Ticker or Trading Symbol OMNICOM GROUP INC. [ OMC] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chairman and CEO (Last) (First) (Middle) C/O OMNICOM GROUP INC., 280 PARK AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 04/23/2021 (Street) NEW YORK, NY10017 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, par value $0.15 per share 04/23/2021 A 139,175 ( 1 ) A $ 0 282,693 ( 2 ) D Common Stock, par value $0.15 per share 04/23/2021 F 58,113 ( 3 ) D $ 81.23 224,580 D Common Stock, par value $0.15 per share 04/26/2021 S 81,062 D $ 80.6845 ( 4 ) 143,518 D Common Stock, par value $0.15 per share 995,167 I By GRATs Common Stock, par value $0.15 per share 30,834 I By 401(K) Plan

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other WREN JOHN C/O OMNICOM GROUP INC. 280 PARK AVENUE NEW YORK, NY10017 X Chairman and CEO Signatures /s/ John D. Wren 04/27/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On March 13, 2018, the reporting person was granted performance restricted stock units ("PRSUs") which vest based on the company's return on equity as compared to that of an industry peer group. On April 23, 2021, the compensation committee of the board of directors of the company determined that the performance criteria had been met, resulting in the vesting of these shares. ( 2 )Since the date of the reporting person's most recently filed Form 4, an aggregate of 551,655 shares were transferred from various Grantor Retained Annuity Trusts to the reporting person's individual brokerage account, 902,943 shares were transferred from the reporting person's individual brokerage account to various Grantor Retained Annuity Trusts and 9,052 shares were transferred from a trust account to a Grantor Retained Annuity Trust. ( 3 )Represents shares withheld by the company for payment of tax liability incident to the vesting of PRSUs originally granted to the reporting person on March 13, 2018. ( 4 )The reported sale price reflects the weighted average price of multiple transactions on April 26, 2021. The actual sales prices for the transactions ranged from $80.50 to $80.90. The reporting person undertakes to provide to Omnicom Group Inc., any security holder of Omnicom Group Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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