A civil lawsuit filed on Friday claims Anthropic, OpenAI, SpaceXAI, and Google violated antitrust laws by agreeing to slow the pace of artificial intelligence development.

The suit, which was filed in the U.S. District Court for the Northern District of California, centers on a Sept. 12 essay Anthropic CEO Dario Amodei wrote that called for the leading AI companies to “pace the frontier” after an employee left the company and subsequently said AI was developing without adequate safety guardrails. Sam Altman, Elon Musk, and Demis Hassabis all quickly agreed with Amodei on social media, the suit argues.