Elon Musk's X has lost tons of advertisers. The platform's solution is to sue them.

• X is suing a group of advertisers, alleging they violated antitrust law.
• The lawsuit alleges an advertising group convinced top brands to withhold billions in ad revenue from X.
• X CEO Linda Yaccarino argues the boycott undermined the marketplace of ideas.

Elon Musk's X is suing a group of advertisers, alleging that they violated antitrust laws by ganging up on the social media company in an advertising boycott.

X CEO Linda Yaccarino posted a video and an open letter on the platform on Tuesday announcing the lawsuit against the Global Alliance for Responsible Media (GARM), the World Federation of Advertisers, as well as GARM members CVS Health, Mars, Orsted, and Unilever.

The lawsuit, filed in Texas, argues that after Musk took over the platform in 2022, GARM convinced top brands not to advertise on X in an effort to "collectively withhold billions of dollars in advertising revenue" from the platform, The New York Times reported.

"The consequence - perhaps the intent - of this boycott was to seek to deprive X's users, be they sports fans, gamers, journalists, activists, parents or political and corporate leaders, of the Global Town Square," Yaccarino wrote in the letter. "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."

Musk also weighed in on the lawsuit in several posts on X.

"I strongly encourage any company who has been systematically boycotted by advertisers to file a lawsuit," Musk wrote in one post. "There may also be criminal liability via the RICO Act."

Since Musk took over the platform (formerly Twitter) and began reshaping it — slashing its moderation team, laying off workers, and declaring the platform a haven of "free speech" — advertisers have fled, dealing a crippling blow to X's advertising revenues.

The advertisers left after critics noted antisemitic and hateful rhetoric on the platform.

Documents obtained by Bloomberg show X lost roughly 40% of its revenue in the immediate aftermath of the takeover.

Musk, for his part, has gone on offense. He infamously told advertisers that had left his platform to go "fuck" themselves in November 2023.

Since then, he's tried to woo advertisers back. It's not clear that'll work, Business Insider's Peter Kafka wrote last month.