ChatGPT users have filed a lawsuit against Microsoft, claiming the tech giant “mercilessly” restricted OpenAI’s compute supply through an exclusive Azure cloud deal, leading to inflated AI subscription prices while Microsoft rushed its own AI products to market.

The suit, filed Monday in San Francisco federal court, alleges that Microsoft turned an investment into a stranglehold, using its Azure dominance to limit the computational resources needed to run ChatGPT. According to the plaintiffs, this kept subscription costs at 100 to 200 times the rates of competitors during a February 2025 AI price war.

Eleven ChatGPT Plus subscribers claim they overpaid for services and experienced degraded performance from November 2022 through February 2025 due to Microsoft’s alleged anticompetitive conduct.

The lawsuit describes the case as a “sequel to U.S. v. Microsoft,” referencing the company’s 1990s antitrust battles, and calls Microsoft a “recidivist violator” applying a similar exclusionary strategy in the AI space.

According to the filing, Microsoft’s 2019 exclusive compute agreement with OpenAI gave it control over a horizontal competitor’s supply chain while it developed its own generative AI offerings, effectively limiting competition.