Anthropic PBC confidentially submitted a draft Form S-1 to the SEC on Monday, less than a week after closing a $65 billion Series H at a $965 billion post-money valuation. The Claude developer published the disclosure under Rule 135 of the Securities Act of 1933, noting that any offering will depend on market conditions.
The sequencing is the story. Six months ago, in December 2025, Anthropic carried a $183 billion valuation. It now sits above OpenAI’s $852 billion mark, set in March after a $122 billion raise, and its annualized revenue run rate has reached $47 billion, up from $10 billion in annual revenue the prior year. That’s the kind of curve underwriters build entire roadshows around.
It’s also a curve built on someone else’s silicon. CNBC, reading SpaceX’s own prospectus, reports Anthropic will pay $1.25 billion per month through May 2029 for compute capacity at the Colossus 1 data center in Memphis. Either party can terminate on 90 days’ notice. The Claude business and the Starlink balance sheet are now load-bearing for each other.
The filing slots into a tight calendar. SpaceX filed its public S-1 on May 20 and is targeting a Nasdaq listing on June 12 under SPCX at a $1.75 trillion to $1.8 trillion valuation. OpenAI confidentially filed its own draft around May 22, aiming for a September debut above $1 trillion. Anthropic, founded in 2021 by former OpenAI researchers and led by siblings Dario and Daniela Amodei, has now joined the queue.
A confidential filing can be withdrawn at any time, and an official prospectus must reach investors at least 15 days before a roadshow. The Amodei siblings have bought themselves optionality against a market that, for now, is willing to treat compute contracts as growth stories.