Anthropic confidentially submitted a draft Form S-1 to the U.S. Securities and Exchange Commission on Monday. The company posted a one-paragraph statement confirming the filing, the standard “this gives us the option to go public after the SEC completes its review” language, and the standard “the proposed initial public offering will depend on market conditions” disclaimer. The number of shares and the price range are not in the filing. Almost nothing is in the filing that the public will get to see for several months. That is the point of a confidential S-1: you let the SEC redline your numbers before the rest of the world gets to read them.
The interesting context is everything around the document. Last Thursday’s Series H closed at a $965 billion post-money valuation on a $65 billion check. The annualized revenue run rate Anthropic disclosed alongside that round was $47 billion, up from roughly $10 billion at the end of 2025. The comp on the OpenAI side is a $852 billion mark from March, and OpenAI is reportedly preparing its own confidential filing in the next few weeks. Two private companies valued at a combined $1.8 trillion are now racing each other onto public markets that have spent the last eighteen months trying to figure out how to value any of this.
What this filing actually does is start the SEC review clock. Best case for Anthropic, the IPO lands in the back half of 2026 with a road show in Q3. More likely, it lands in 2027 once the SEC has chewed through the disclosures around compute commitments, model lifecycle accounting, and exactly how the revenue line scales against the inference cost line. The latter is the question every public-market analyst will eventually have to answer in writing, which is roughly the opposite of how private rounds get done. The procurement teams who have been buying Claude Code on annual contracts are about to discover their vendor’s margin profile in a 10-Q.