Cover and table of contents

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

FOR THE FISCAL YEAR ENDED DECEMBER 31, 2024

Commission File Number: 1-10551

OMNICOM GROUP INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (212) 415-3600

Securities Registered Pursuant to Section 12(b) of the Act:

Securities Registered Pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes þ No o

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes o No þ

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes þ No o

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of the chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes þ No o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☑

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to § 240.10D-1(b). o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ☐ No þ

The aggregate market value of the voting and non-voting common stock held by non-affiliates as of June 30, 2024 was $17,486,183,571. As of January 30, 2025, there were 196,490,662 shares of Omnicom Group Inc. Common Stock outstanding.

Portions of the Omnicom Group Inc. Definitive Proxy Statement for the Annual Meeting of Shareholders planned to be held on May 6, 2025 are incorporated by reference into Part III of this report to the extent described herein.

OMNICOM GROUP INC.

ANNUAL REPORT ON FORM 10-K FOR THE YEAR ENDED DECEMBER 31, 2024

TABLE OF CONTENTS

i

FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements, including statements within the meaning of the Private Securities Litigation Reform Act of 1995. In addition, from time to time, the Company or its representatives have made, or may make, forward-looking statements, orally or in writing. These statements may discuss goals, intentions and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the Company’s management as well as assumptions made by, and information currently available to, the Company’s management. Forward-looking statements may be accompanied by words such as “aim,” “anticipate,” “believe,” “plan,” “could,” “should,” “would,” “estimate,” “expect,” “forecast,” “future,” “guidance,” “intend,” “may,” “will,” “possible,” “potential,” “predict,” “project” or similar words, phrases or expressions. These forward-looking statements are subject to various risks and uncertainties, many of which are outside the Company’s control. Therefore, you should not place undue reliance on such statements. Factors that could cause actual results to differ materially from those in the forward-looking statements include:

• risks relating to the pending Merger (as defined below) with The Interpublic Group of Companies, Inc., or IPG, including: that the Merger may not be completed in a timely manner or at all; delays, unanticipated costs or restrictions resulting from regulatory review of the Merger; uncertainties associated with the Merger may cause a loss of both companies’ management personnel and other key employees, and cause disruptions to both companies’ business relationships; the Merger Agreement (as defined below) subjects the Company and IPG to restrictions on business activities prior to the effective time of the Merger; the Company and IPG are expected to incur significant costs in connection with the Merger and integration; litigation risks relating to the Merger; the business and operations of both companies may not be integrated successfully in the expected time frame; the Merger may result in a loss of both companies’ clients, service providers, vendors, joint venture participants and other business counterparties; and the combined company may fail to realize all of the anticipated benefits of the Merger or fail to effectively manage its expanded operations;

• adverse economic conditions, including geopolitical events, international hostilities, acts of terrorism, public health crises, inflation or stagflation, tariffs and other trade barriers, central bank interest rate policies in countries that comprise our major markets and labor and supply chain issues affecting the distribution of our clients’ products, or a disruption in the credit markets;

• international, national or local economic conditions that could adversely affect the Company or its clients,

• losses on media purchases and production costs incurred on behalf of clients;

• reductions in client spending, a slowdown in client payments or a deterioration or disruption in the credit markets;

• the ability to attract new clients and retain existing clients in the manner anticipated;

• changes in client marketing and communications services requirements;

• failure to manage potential conflicts of interest between or among clients;

• unanticipated changes related to competitive factors in the marketing and communications services industries;

• unanticipated changes to, or the ability to hire and retain key personnel;

• currency exchange rate fluctuations;

• reliance on information technology systems and risks related to cybersecurity incidents;

• effective management of the risks, challenges and efficiencies presented by utilizing Artificial Intelligence (AI) technologies and related partnerships in our business;

• changes in legislation or governmental regulations affecting the Company or its clients;

• risks associated with assumptions the Company makes in connection with its acquisitions, critical accounting estimates and legal proceedings;

• the Company’s international operations, which are subject to the risks of currency repatriation restrictions, social or political conditions and an evolving regulatory environment in high-growth markets and developing countries; and

• risks related to our environmental, social and governance goals and initiatives, including impacts from regulators and other stakeholders, and the impact of factors outside of our control on such goals and initiatives.

The foregoing list of factors is not exhaustive. You should carefully consider the foregoing factors and the other risks and uncertainties that may affect the Company’s business, including those described in Item 1A., “Risk Factors” and Item 7., “Management’s Discussion and Analysis of Financial Condition and Results of Operations”, or MD&A, in this report and in other documents filed from time to time with the Securities and Exchange Commission, or SEC. Except as required under applicable law, the Company does not assume any obligation to update these forward-looking statements.

ii

ADDITIONAL INFORMATION ABOUT THE TRANSACTION WITH IPG AND WHERE TO FIND IT

In connection with the proposed transaction, Omnicom and IPG have filed a joint proxy statement with the SEC on January 17, 2025 and Omnicom has filed with the SEC a registration statement on Form S-4 on January 17, 2025 (File No. 333-284358) (“Form S-4”) that includes the joint proxy statement of Omnicom and IPG and that also constitutes a prospectus of Omnicom. Each of Omnicom and IPG may also file other relevant documents with the SEC regarding the proposed transaction. This annual report on Form 10-K is not a substitute for the joint proxy statement/prospectus or registration statement or any other document that Omnicom or IPG may file with the SEC. The definitive joint proxy statement/prospectus have been mailed to stockholders of Omnicom and IPG. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE REGISTRATION STATEMENT, JOINT PROXY STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS THAT HAVE BEEN AND MAY BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY IF AND WHEN THEY BECOME AVAILABLE BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT OMNICOM, IPG AND THE PROPOSED TRANSACTION.

Investors and security holders are able to obtain free copies of the registration statement and joint proxy statement/prospectus and other documents containing important information about Omnicom, IPG and the proposed transaction, through the website maintained by the SEC at http://www.sec.gov. Copies of the registration statement and joint proxy statement/prospectus and other documents (if and when available) filed with the SEC by Omnicom may be obtained free of charge on Omnicom’s website at https://investor.omnicomgroup.com/financials/sec-filings/default.aspx or, alternatively, by directing a request by mail to Omnicom’s Corporate Secretary at Omnicom Group Inc., 280 Park Avenue, New York, New York 10017. Copies of the registration statement and joint proxy statement/prospectus (if and when available) and other documents filed with the SEC by IPG may be obtained free of charge on IPG’s website at https://investors.interpublic.com/sec-filings/financial-reports or, alternatively, by directing a request by mail to IPG’s Corporate Secretary at The Interpublic Group of Companies, Inc., 909 Third Avenue, New York, NY 10022, Attention: SVP & Secretary.

PARTICIPANTS IN THE SOLICITATION

Omnicom, IPG and certain of their respective directors and executive officers may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information about the directors and executive officers of Omnicom, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in this Annual Report on Form 10-K, including under the heading “Information About Our Executive Officers,” and proxy statement for Omnicom’s 2024 Annual Meeting of Stockholders, which was filed with the SEC on March 28, 2024, including under the headings “Executive Compensation,” “Omnicom Board of Directors,” “Directors’ Compensation for Fiscal Year 2023” and “Stock Ownership Information.” To the extent holdings of Omnicom common stock by the directors and executive officers of Omnicom have changed from the amounts reflected therein, such changes have been or will be reflected on Initial Statements of Beneficial Ownership of Securities on Form 3 (“Form 3”), Statements of Changes in Beneficial Ownership on Form 4 (“Form 4”) or Annual Statements of Changes in Beneficial Ownership of Securities on Form 5 (“Form 5”), subsequently filed by Omnicom’s directors and executive officers with the SEC. Information about the directors and executive officers of IPG, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in IPG’s Annual Report on Form 10-K, including under the heading “Executive Officers of the Registrant,” and proxy statement for IPG’s 2024 Annual Meeting of Stockholders, which was filed with the SEC on April 12, 2024, including under the headings “Board Composition,” “Non-Management Director Compensation,” “Executive Compensation” and “Outstanding Shares and Ownership of Common Stock.” To the extent holdings of IPG common stock by the directors and executive officers of IPG have changed from the amounts reflected therein, such changes have been or will be reflected on Forms 3, Forms 4 or Forms 5, subsequently filed by IPG’s directors and executive officers with the SEC.

iii

PART I

Introduction

This report is our 2024 annual report to shareholders and our 2024 Annual Report on Form 10-K, or 2024 10-K.

Omnicom Group Inc., a New York corporation, was formed in 1986. The terms “Omnicom,” “the Company,” “we,” “our” and “us” each refer to Omnicom Group Inc. and its subsidiaries unless the context indicates otherwise.