June 12 (Reuters) – The U.S. Federal Trade Commission, reviewing a proposed merger by leading advertising companies Omnicom and Interpublic, may impose a condition that will prevent the combined company from boycotting ads on platforms because of political content, a source familiar with the matter said on Thursday.

Omnicom (OMC.N), opens new tab struck a $13.25 billion all-stock deal, opens new tab in December to buy rival Interpublic Group (IPG.N), opens new tab, creating the world’s largest advertising agency.

The deal is under review by the FTC and no agreement has been finalized, the source said. The FTC, along with the Federal Communications Commission, has spearheaded the Trump administration’s efforts to address perceived political bias in corporate America against conservatives.

The ad companies did not immediately respond to requests for comment. The New York Times earlier reported the potential settlement.

The combined company, with revenue of more than $25 billion based on 2023 figures, would compete with some of the world’s largest advertising groups, including WPP (WPP.L), opens new tab and Publicis (PUBP.PA), opens new tab.

Omnicom expects to close the acquisition in the second half of the year.

The FTC has sought information from some of the world’s top ad firms as part of a probe into whether advertising and advocacy groups violated antitrust laws by coordinating boycotts of certain sites.

FTC Chairman Andrew Ferguson has said group boycotts by advertisers can be illegal because they involve coordinated refusals to do business, which may restrict competition.

Ad spending on X had slumped for months after billionaire Elon Musk bought the platform in October 2022, as some advertisers were wary of buying ads on the platform amid concerns that their brands would appear next to harmful content or false claims.

In March, a group of senators, opens new tab including Cory Booker and Elizabeth Warren raised concerns about Musk potentially influencing the review of the Omnicom-Interpublic deal through his role in the Trump administration. They asked U.S. regulators to independently evaluate the proposed transaction.