A group of paying users initiated a class action lawsuit in California federal court to block a suspected agreement to limit the growth of artificial intelligence. The complaint alleges that Anthropic, OpenAI, SpaceXAI, and Google violated Section 1 of the Sherman Act by coordinating a slowdown in capability growth, which plaintiffs characterize as a restraint that reduces output for subscribers. The lawsuit seeks an injunction and treble damages for a nationwide class of people paying for the four assistants.

The alleged pact began September 12 when Anthropic CEO Dario Amodei urged industry coordination to curb unchecked progress, a proposal publicly supported by executives at the other three firms that same day. Plaintiffs argue that collective restraint removes the competitive penalty of losing revenue and talent that a company would face if it slowed development independently. The filing specifies it does not challenge government regulation, environmental safeguards, or unilateral safety testing.