The Interpublic Group of Companies, Inc. (IPG)

The Interpublic Group of Companies, Inc. was one of the largest advertising and marketing services holding companies in the world, headquartered in New York City. Its origins trace to the McCann-Erickson agency, and the Interpublic name was adopted in 1961 as the holding company for McCann-Erickson and its affiliated agencies. Over the following decades it assembled a network of creative, media and communications firms operating in more than a hundred countries.

Interpublic's portfolio included global agency brands such as McCann Worldgroup, FCB, MullenLowe and R/GA, the media agencies UM and Initiative within IPG Mediabrands, and public relations and communications firms including Weber Shandwick and Golin. It also owned data, commerce and healthcare marketing businesses. Its clients included large multinational consumer, technology, healthcare and financial services companies.

The company's shares traded on the New York Stock Exchange under the symbol IPG. In the 2020s it reorganized its reporting around integrated agency networks and a group of specialized businesses, and it invested in data and technology capabilities, including acquisitions in digital commerce and analytics. Like its competitors, it faced pressure from changing client budgets, in-house agency models, the growth of digital platforms and the emergence of generative artificial intelligence in content and media planning.

On December 9, 2024, Interpublic and Omnicom Group Inc. announced a definitive agreement to combine in an all-stock transaction in which each share of Interpublic common stock would be exchanged for 0.344 of a share of Omnicom common stock. Omnicom was the legal acquirer, and the combined company would operate under the Omnicom name with John Wren as chairman and chief executive officer. The companies projected substantial annual cost synergies and said that the combination would create a company with revenue well above the level of either predecessor.

The deal required approval by both companies' shareholders, which was received in early 2025, along with regulatory reviews in the United States, Europe and other jurisdictions. The U.S. Federal Trade Commission cleared the deal in mid-2025 subject to a consent order that restricted the combined company from coordinating advertising decisions based on political or ideological viewpoints. Remaining approvals, including that of the European Commission, were obtained in the fall.

The transaction closed on November 26, 2025, and Interpublic became a wholly owned subsidiary of Omnicom. Its common stock stopped trading on the NYSE, and a Form 25 was filed with the SEC on November 28, 2025 to remove the shares from listing and registration. Former Interpublic shareholders received Omnicom shares, which trade on the New York Stock Exchange under the symbol OMC.