OMNICOM GROUP INC.

In accordance with the rules promulgated by the SEC, we have elected to provide access to our proxy materials on the Internet. This Proxy Statement and our 2025 Annual Report to Shareholders are available, beginning March 26, 2026, on our website at https://investor.omc.com. You may also access our Proxy Statement and our 2025 Annual Report to Shareholders at https://materials.proxyvote.com/681919. You also may obtain a copy of this document, our 2025 Annual Report to Shareholders, our Corporate Governance Guidelines, our Code of Business Conduct, our Code of Ethics for Senior Financial Officers and the charters for our Audit, Compensation, Governance and Finance Committees, without charge, by writing to: Omnicom Group Inc., 280 Park Avenue, New York, New York 10017, Attn: Corporate Secretary. All of these documents are also available after being approved by the Board through our website at https://www.omc.com. Please note that the information contained on our website is not incorporated by reference in, or considered to be part of, this Proxy Statement.