Mark D. Gerstein - 01 Oct 2025 Form 4 Insider Report for OMNICOM GROUP INC. (OMC)

Role: Director
Signature: /s/ Eric J. Cleary, Attorney in Fact for Mark D. Gerstein
Issuer symbol: OMC
Transactions as of: 01 Oct 2025
Net transactions value: $0
Form type: 4
Filing time: 03 Oct 2025, 16:34:14 UTC
Previous filing: 03 Jul 2025
Next filing: 05 Jan 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Gerstein Mark D	Director	C/O OMNICOM GROUP INC., 280 PARK AVENUE, NEW YORK	/s/ Eric J. Cleary, Attorney in Fact for Mark D. Gerstein	03 Oct 2025	0001916341

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	OMC	Common Stock, par value $0.15 per share	Award	$0	+629	+5.2%	$0.000000	12,755	01 Oct 2025	Direct	F1, F3
transaction	OMC	Common Stock, par value $0.15 per share	Award	$0	+276	+2.2%	$0.000000	13,031	01 Oct 2025	Direct	F2, F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The reporting person elected to defer receipt of these shares under the terms of the Omnicom Group Inc. 2021 Incentive Award Plan.
F2	The reporting person elected to defer receipt of these shares, which represent a quarterly payment of his annual retainer, under the terms of the Omnicom Group Inc. 2021 Incentive Award Plan.
F3	Includes dividends on deferred shares that are reinvested in company stock, credited on July 9, 2025.