Omnicom (OMC) 4: Gerstein Mark D bought 635 shares of Common Stock, par valu… (Jan 5, 2026)

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-01-01 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: OMNICOM GROUP INC. (OMC) CIK: 0000029989 --- Reporting Owner --- Name: Gerstein Mark D CIK: 0001916341 Role: Director --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock, par value $0.15 per share Date: 2026-01-01 | Code: A (Grant or award) Shares: +634.68 | Price: $0.00 Shares Owned After: 13,776.68 | Ownership: D (Direct) Footnotes: [F1] The reporting person elected to defer receipt of these shares 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 October 10, 2025. [Transaction #2] Security: Common Stock, par value $0.15 per share Date: 2026-01-01 | Code: A (Grant or award) Shares: +278.64 | Price: $0.00 Shares Owned After: 14,055.32 | Ownership: D (Direct) Footnotes: [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 October 10, 2025. --- Footnotes (Complete Index) --- 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 October 10, 2025. --- Signature --- /s/ /s/ Eric J. Cleary, Attorney in Fact for Mark D. Gerstein (2026-01-05)