The filing

On 18 September 2026, counsel for Trial Lawyers for Justice filed Buist et al. v. Anthropic, PBC; OpenAI OpCo, LLC; SpaceXAI LLC; and Google LLC in the United States District Court for the Northern District of California, San Francisco Division. Case number 3:26-cv-10693. Document 1 is a 29-page class action complaint with a jury demand.

Named plaintiffs: Charles Buist (Florida), Cheyenne Hunt (California), Christine Bullock (California), and Nick Spetsas (Florida). Each alleges a paid individual consumer subscription to one or more of the defendants' frontier chat products during the class period.

Defendants named on the caption:

  • Anthropic, PBC (Claude Pro / Max)
  • OpenAI OpCo, LLC (ChatGPT Plus and related paid tiers as pleaded)
  • SpaceXAI LLC (Grok)
  • Google LLC (paid Gemini access as pleaded)

Lead counsel listed includes Nicholas C. Rowley, Andrew T. Tutt, R. Stanton Jones, and Jakob Z. Norman of Trial Lawyers for Justice.

What the complaint alleges

Paragraph 1 frames the case as a challenge to an agreement among the four frontier companies "to slow the pace at which each company improves the competing products it sells to consumers."

The formation story in the introduction and factual allegations is built from public statements:

  1. On the morning of 12 September 2026, Anthropic CEO Dario Amodei published We Must Pace the Frontier, calling for industry-wide coordination and limits on the rate of unchecked AI progress, including language that coordinated slowing would let each participant reduce its pace "without sacrificing commercial advantage."
  2. Same day, Elon Musk (pleaded as controlling SpaceXAI's Grok business) quote-posted: "Dario is right."
  3. Same day, OpenAI CEO Sam Altman wrote that he agreed they need to "pace the frontier" and committed OpenAI to the essay's first concrete step on independent evaluators.
  4. Same day, Google DeepMind co-founder Demis Hassabis called the essay "the right path forward" and tied it to an industry-wide standards body for frontier AI.
  5. On 14 September, Altman said AI progress "should be slower than it otherwise could be," and that OpenAI would not wait for an antitrust exemption before working with "colleagues across the industry."
  6. On 15 September, OpenAI's Global Policy Chief (named in the complaint as Lehane) is pleaded as confirming weeks of collaboration among OpenAI, Anthropic, and Google DeepMind, including a working group meeting since July.

The complaint characterizes the arrangement as a naked horizontal restraint on output and product quality among competitors, pleaded as unlawful per se under Section 1 of the Sherman Act, 15 U.S.C. § 1, with alternative quick-look and rule-of-reason theories. Injury theory: paid subscribers receive a slower rate of capability improvement for the subscription price they pay, pleaded as an overcharge under Clayton Act § 4.

The complaint expressly disclaims a challenge to unilateral safety measures, independent slowing, independent evaluators, petitioning government, or legitimate standard-setting that does not restrain independent competition over pace. The target, as pleaded, is only a horizontal agreement among competitors about how fast competing products will improve.

Class and subclasses

Nationwide Class (¶123): all persons in the United States who, from 12 September 2026 through the date effects of the alleged conduct cease (the Class Period), purchased directly from one or more Defendants a paid individual consumer subscription providing premium access to ChatGPT, Claude, Grok, or Gemini.

Defendant-specific subclasses are pleaded for OpenAI, Anthropic, SpaceXAI, and Google subscribers. Exclusions include defendants and affiliates, government entities, and judges. Plaintiffs reserve the right to move the start date earlier if discovery shows earlier formation.

Relief sought

Prayer for relief asks the Court to:

  • Certify the class and appoint class counsel
  • Adjudge a Section 1 violation
  • Award damages to be established at trial, trebled under Clayton Act § 4
  • Enter preliminary and permanent injunctive relief under Clayton Act § 16 against continuing, renewing, enforcing, or implementing any horizontal agreement to restrain competitive innovation
  • Award interest, fees, and costs
  • Grant other just relief

The requested injunction language (¶150) would bar agreements among horizontal competitors concerning rate of development/release, compute or training-run limits adopted pursuant to a pacing arrangement, agreed limits on AI-led AI R&D, coordinated delays, capability checkpoints used as horizontally agreed restraints, and exchange of competitively sensitive information to police such restraints.

What this piece is for

This investigation maps the filed complaint as an evidence artifact: parties, docket, theory of agreement, class, and relief. Answers, motions to dismiss, and any finding of liability are UNKNOWN on this docket as of draft. Public CEO essays and X posts are what the complaint cites as manifestation. Whether those statements legally constitute a contract, combination, or conspiracy is a question for the court. The Frontier's earlier pace-frontier-vs-ipo claim-check tested CapEx and IPO clocks against the essay language. This filing is a separate document trail.