Workers at OpenAI show support for Anthropic as the company says it could lose $5 billion in its feud with the Pentagon

• Anthropic faces a $5 billion loss due to its feud with the Pentagon, the company said in a court filing.
• OpenAI and Google researchers signed an amicus brief in support of Anthropic.
• Anthropic is seeking a court order to continue Pentagon work while the legal case plays out.

Employees at rival companies — including OpenAI — are rallying behind Anthropic as the startup warns its escalating dispute with the Pentagon could cost $5 billion in lost business.

More than 30 researchers from OpenAI and Google, including Jeff Dean, the chief scientist of Google DeepMind, filed a joint amicus brief on Monday supporting Anthropic in its legal battle with the government. The employees signed in a personal capacity and do not represent their companies' official views.

Their filing argues that the Pentagon's decision to label Anthropic a "supply-chain risk" could harm the broader US AI industry.

"If allowed to proceed, this effort to punish one of the leading US AI companies will undoubtedly have consequences for the United States' industrial and scientific competitiveness in the field of artificial intelligence and beyond," the employees wrote.

The dispute stems from a breakdown in negotiations between Anthropic and the Pentagon over guardrails around how its AI models could be used, particularly around mass domestic surveillance and autonomous lethal weapons.

Last month, Defense Secretary Pete Hegseth said that "no contractor, supplier, or partner that does business with the United States military may conduct any commercial activity with Anthropic," marking a dramatic expansion of the "supply chain risk" designation.

Anthropic has since sued the government in two courts, arguing the decision violates its First Amendment rights and unfairly retaliates against the company.

In court filings, Anthropic executives warned that the fallout is already hitting the company's finances. Chief financial officer Krishna Rao wrote in a court statement that hundreds of millions of dollars in expected revenue tied to Pentagon-related work are at risk this year. If the government succeeds in discouraging companies from working with Anthropic more broadly, Rao added, the company could ultimately lose up to $5 billion in sales, which is roughly equivalent to its total revenue since commercializing its AI technology in 2023.

Anthropic's chief commercial officer, Paul Smith, wrote in a separate court statement that the pressure from the government is causing business partners to take steps that "reflect deep distrust and a growing fear of associating with Anthropic." Smith added that some customers have paused negotiations or demanded escape clauses, while others have canceled meetings entirely after the supply-chain designation.

The situation has also drawn criticism from industry leaders. OpenAI CEO Sam Altman, despite singing its own contract with the Pentagon after Anthropic's fell apart, wrote on social media that enforcing the supply chain risk designation "would be very bad for our industry and our country."

Major cloud providers like Amazon and Microsoft have said they will continue offering Anthropic's Claude AI models to customers without ties to the Pentagon.

Anthropic is now seeking a temporary court order that would allow it to continue working with military contractors while the legal fight continues. The first hearing could take place in San Francisco as soon as Friday.

The Pentagon did not immediately respond to a request for comment outside normal business hours.