Anthropic is quietly doing everything a company does right before it goes public. The AI safety firm filed a confidential draft registration statement on Form S-1 with the SEC on June 1, 2026. Prediction markets now put the odds of an IPO completing by October 31 at roughly 90%.
For context on the stakes: Anthropic’s most recent funding round, a $65 billion Series H, pushed its valuation to approximately $965 billion.
What just shipped
On September 1, Anthropic launched Claude Fable 5.1 in general availability and Claude Mythos 5.1 in limited release. Both models are built around reasoning and coding performance, and both carry a 1 million-token context window, which is large enough to ingest an entire codebase or a multi-year document archive in a single prompt.
Pricing is tiered at $10 per million input tokens and $50 per million output tokens.
