The US Justice Department filed a notice of appeal with the Ninth Circuit on Monday, October 26 — the same day Anthropic publicly filed its IPO prospectus — seeking to overturn a California court's ruling that blocked a government-wide ban on Claude. The California judge had found the government had not provided sufficient evidence of risk and that the ban amounted to retaliation for Anthropic's public criticism.

Separately, the Federal Trade Commission sent demands for Anthropic executives to testify in its consumer-harm probe, an FTC spokesperson told Axios. The FTC is investigating both Anthropic and OpenAI and has sent civil subpoenas to both companies seeking documents about safety incidents; executives at other AI companies have also received demands.

Anthropic's prospectus puts government contracts at about 1% of revenue, but the court record cited three contractor deals ended or ordered ended and three more deals worth over $180 million that fell through. Anthropic previously estimated a fully implemented ban could cut its 2026 revenue by several billion dollars. A Washington appeals court has separately allowed the Pentagon to exclude Claude from military systems on supply-chain risk grounds.