Elon Musk’s X Corp., formerly known as Twitter, filed a lawsuit accusing the Global Alliance for Responsible Media (GARM) of violating antitrust laws for an advertising boycott that cost the social media company billions of dollars.

The lawsuit, filed Tuesday in federal court in Texas, claims the industry group coordinated the boycott of the platform by advertisers under the guise of concern about whether X would adhere to certain brand safety standards. 

Also read: House grills Unilever and GroupM exec alleging collusion against X, right-wing sites

“To put it simply, people are hurt when the marketplace of ideas is undermined and some viewpoints are not funded over others as part of an illegal boycott,” X CEO Linda Yaccarino said in a post on the platform. “This behavior is a stain on a great industry, and cannot be allowed to continue.”

GARM’s more than 100 members include advertisers including Procter & Gamble Co. and Unilever Plc, as well as tech companies such as Meta Platforms Inc., Alphabet Inc.’s YouTube and ByteDance Ltd.’s TikTok.

In its 2022 annual report, the industry group said it had helped establish common definitions, metrics and tools to aid brands and their advertising partners in ensuring their ads don’t appear alongside content they may find problematic.

The lawsuit comes after House Republicans accused the group of violating antitrust laws that bar agreements restricting trade.

The case is X v. World Federation of Advertisers, 7:24-cv-00114, US District Court, Northern District of Texas (Wichita Falls).

The lawsuit drew a strong reaction on social media, including criticism from the X account of Interpublic-owned agency R/GA.

—Bloomberg News with Ad Age contributions