The letter reviewed by ADWEEK was issued by the FTC’s mergers division, prompting speculation that the CID letters may be part of a larger investigation concerning Omnicom’s planned acquisition of IPG. In March, the FTC issued a second request for information concerning the proposed transaction.

Following the government’s scrutiny into GARM last year, X—under the leadership of polarizing billionaire owner Elon Musk—sued the organization over similar allegations, accusing the group and its backer, the World Federation of Advertisers, of operating as gatekeepers that pressure brands into boycotts of sites like X under the guise of brand safety. GARM shuttered days after the lawsuit was launched.

Musk has also sued Media Matters. In his lawsuit, Musk alleges the group knowingly manipulated data to push a damaging narrative about X after it published research highlighting racist and antisemitic content on X. The organization snapped back with a lawsuit of its own in March. 

“Businesses have rights to not advertise next to stuff they find crappy,” Otero told ADWEEK. “And no one is colluding with anybody about this.”