Four consumers filed a federal lawsuit Friday accusing Anthropic, OpenAI, SpaceX AI and Google of violating antitrust law by coordinating efforts to slow the pace of AI development. The complaint was filed in the U.S. District Court for the Northern District of California and seeks class-action status on behalf of consumers who subscribe to the companies’ AI services.

The lawsuit centers on an essay published Sept. 12 by Anthropic CEO Dario Amodei titled “We Must Pace the Frontier.” Amodei called for industrywide coordination to slow the development of increasingly capable AI systems while safety testing catches up.

OpenAI CEO Sam Altman, SpaceX AI founder Elon Musk and Google DeepMind co-founder Demis Hassabis subsequently expressed support for Amodei’s proposal. The plaintiffs argue that the companies’ public agreement to limit the pace at which their competing products improve amounts to an unlawful restraint of trade under Section 1 of the Sherman Act.

The consumers argue that a coordinated slowdown could reduce the improvements customers receive from paid AI products, including ChatGPT, Claude, Grok and Gemini. They are seeking class-action certification, an injunction and a declaration that the alleged agreement violates federal antitrust law.

Nick Rowley, an attorney representing the plaintiffs, argued that decisions about AI safeguards should be made through government policy rather than private agreements among major technology companies. The complaint also points to Amodei's proposal for government involvement in facilitating joint industry safety discussions, potentially through a narrowly tailored antitrust exemption.

The proposal has drawn opposition in Washington. Sen. Josh Hawley, R-Mo., said during a Senate Judiciary Committee hearing that he would not support giving an antitrust exemption to major technology companies to coordinate on AI safety.

The lawsuit comes amid a broader debate over whether the rapid development of increasingly capable AI systems should continue at its current pace. Some technology executives have called for additional safety measures, while others have warned that slowing development could undermine competition and innovation. President Donald Trump has also opposed calls for a broad slowdown in AI development.

The allegations in the lawsuit have not been proven in court, and the defendants had not immediately responded to requests for comment when the case was filed.