The filing does not set a share count or price. Anthropic said the offering would depend on SEC review, market conditions and other factors, and AP reported that the company had not decided how many shares it would offer or at what price.
The confidential filing follows Anthropic's 28 May announcement that it raised $65bn in Series H funding at a $965bn post-money valuation. Anthropic said the round was led by Altimeter Capital, Dragoneer, Greenoaks and Sequoia Capital; AP and Axios separately reported the same valuation and round size.
A confidential draft S-1 lets a company receive SEC comments before it makes a registration statement public. Anthropic's public notice said the announcement was made under Rule 135 of the Securities Act and was not an offer to sell securities. AP reported that the public S-1, when filed, would be expected to give investors the first detailed look at the company's financials, risks and ownership structure.
Anthropic also said its run-rate revenue crossed $47bn in May. Run-rate revenue is an annualized estimate based on current revenue, not audited annual revenue, and the company has not yet published a public prospectus containing financial statements. AP reported the same $47bn annualized figure and said the company, like other large AI firms moving toward public markets, is still losing more money than it makes.
The funding round raised Anthropic's valuation from a reported $380bn in February 2026, according to AP and Axios coverage of the May financing. Axios reported that OpenAI's most recent private valuation was $730bn, while AP said OpenAI was last reported in March to be heading toward an $852bn valuation after a fundraising round. The figures are private-market valuations reported at different dates and are not direct stock-market comparisons.