A proposed class action filed Friday in Northern District of California alleges the four labs agreed to coordinate a slower pace of AI improvement after Amodei’s “Pace the Frontier” essay — claims the companies have not answered in court.
Four paid subscribers to ChatGPT, Claude, Grok, or Gemini filed a proposed nationwide class action on Friday, September 18, 2026, in the U.S. District Court for the Northern District of California naming Anthropic, OpenAI, SpaceXAI, and Google. The complaint, Buist v. Anthropic PBC, argues the labs formed an illegal horizontal agreement to slow how fast each improves competing consumer products, violating Sherman Act Section 1, and that coordinated pacing reduces the value of paid AI subscriptions. Fortune, AP via OPB, and The Hill covered the filing over the weekend. These are allegations; no court has ruled, and the companies did not immediately respond to Saturday comment requests, AP said.
What the complaint points to
Plaintiffs say coordination crystallized around September 12, when Anthropic CEO Dario Amodei published “We Must Pace the Frontier,” urging industry-wide deceleration for safety. The same day, OpenAI CEO Sam Altman, SpaceXAI CEO Elon Musk, and Google DeepMind co-founder Demis Hassabis each responded publicly in ways the complaint treats as agreement. The suit also cites a July 2026 multi-lab employee statement acknowledging “intense competitive pressure not to unilaterally slow.”
Amodei’s essay said a “narrow waiver” for certain safety conversations would help. Altman said OpenAI welcomes a federal safety framework but does not believe labs need to wait for an antitrust exemption. The Next Web, citing Bloomberg Law, notes the complaint’s reply: no such waiver exists. Alleged mechanisms include limits on training compute and runs, restrictions on using AI to improve AI, and capability checkpoints.
Who is suing, and what they want
Named plaintiffs include Charles Buist, Nick Spetsas, Cheyenne Hunt, and Christine Bullock, per The Hill. They say they do not object to unilateral safety slowdowns or to asking Congress for an exemption — they object to rivals agreeing together without that cover. The complaint seeks treble damages, an injunction, and a jury trial. President Trump has rejected slowdown calls and floated an AI task force and “AI czar”; Sen. Josh Hawley has opposed an antitrust exemption for frontier labs. None of that resolves the civil case.
This brief covers weekend major-outlet reporting on the Buist filing. It is not a finding of collusion, and it is distinct from Anthropic’s Accenture embedded-evaluation partnership and from prior coverage of Amodei’s pacing essay.
Sources
- https://fortune.com/2026/09/19/lawsuit-anthropic-openai-spacexai-google-antitrust-laws-ai-slowdown-subscription-value/
- https://www.opb.org/article/2026/09/20/lawsuit-says-anthropic-openai-spacexai-and-google-made-illegal-agreement-on-ai-slowdown/
- https://thehill.com/policy/technology/6099571-lawsuit-accuses-anthropic-openai-spacexai-google-of-ai-pacing-collusion/
- https://thenextweb.com/news/buist-v-anthropic-antitrust-waiver-evidence-public-agreement