- Anthropic has confidentially filed a draft S-1 with the SEC for a potential IPO, four days after raising $65 billion at a $965 billion valuation, overtaking OpenAI to become the world’s most valuable private AI company.
- PitchBook’s Harrison Rolfes argues the filing’s defining number isn’t the valuation or revenue run rate, but gross margin, never publicly disclosed, which will either validate or collapse three years of private market narrative.
- The filing lands amid a historic IPO season: SpaceX is targeting a $1.8 trillion listing around June 12, Polymarket traders are pricing a 78% chance it closes above $2 trillion on day one, and OpenAI is preparing its own S-1, with Rolfes suggesting Anthropic’s early disclosure may actually hand its rival a strategic advantage.
Anthropic has officially entered the public markets race. Today, Anthropic PBC confidentially submitted a draft registration statement on Form S-1 to the US Securities and Exchange Commission for a proposed initial public offering of its common stock, giving it the option to go public after the SEC completes its review. The number of shares to be offered and the price have not yet been set.
The filing comes four days after a landmark funding announcement. As TFN reported on May 29th, Anthropic raised $65 billion in a Series H round led by Altimeter Capital, Dragoneer, Greenoaks, and Sequoia, valuing it at $965 billion, making it the most valuable private AI company in the world and overtaking rival OpenAI for the first time. OpenAI, which closed a $122 billion round at an $852 billion post-money valuation in March 2026, has since filed its own confidential S-1 with the SEC, targeting a listing as early as September 2026. Annualised revenue at Anthropic has crossed $47 billion, up from $14 billion in February, a more than threefold jump in under four months.
Yet the number that may matter most has never been made public. “Anthropic filing a confidential S-1 today starts the clock on what will be the most scrutinised public offering in tech history, and the number that determines everything is not the $965B valuation or the $47B revenue run rate, it is gross margin, which no one outside Anthropic has ever seen, and which will either validate or collapse the entire narrative the private markets have been pricing for three years,” said Harrison Rolfes, Senior Late-Stage Company Research Analyst at PitchBook.
On the competitive dynamic with OpenAI, Rolfes offers a counterintuitive opinion, “The unconventional read is that OpenAI got the better end of this: Anthropic just volunteered to absorb all the disclosure risk first, and OpenAI now has a free option to watch how institutional investors react to audited frontier AI financials before committing to its own price. If Anthropic’s margins disappoint, OpenAI restructures its story quietly before its roadshow. If the deal is oversubscribed, OpenAI rides the wave with a tailwind and no downside.” He adds a caveat, however, “The ‘free option’ argument holds if OpenAI actually has the flexibility to reprice or restructure its narrative based on what Anthropic’s S-1 reveals – if OpenAI is already deep into its own SEC review and bookbuilding prep, the practical window to adjust is narrower than implied.”
The S-1 also drops into an already white-hot IPO season. SpaceX, which filed for a Nasdaq listing on 20 May under the ticker SPCX, is targeting a raise of at least $75 billion with the roadshow set to begin on 8 June and trading expected to start around 12 June. Bloomberg reported that SpaceX has trimmed its IPO valuation target to at least $1.8 trillion, down from the $2 trillion figure it had been seeking as recently as April. Markets, however, are not convinced it will stay there: Polymarket contracts are pricing a 78% chance that SpaceX closes its first day of trading above $2 trillion, a level that would rank it ahead of Saudi Aramco, Tesla, and Meta Platforms and a 15% probability of closing above $2.8 trillion, which would displace Amazon as the fifth most valuable company in the world.
Rolfes frames the stakes plainly: “Two trillion-dollar-scale filings in two weeks represents the largest concentration of pre-IPO capital ever brought to market simultaneously, and the 2026 window either becomes the most consequential IPO cycle since the dot-com era or the most expensive lesson in narrative-versus-fundamentals that public markets have ever taught.”
The proposed offering will depend on market conditions and other factors, Anthropic noted, and no timeline has been disclosed. With the S-1 now submitted, the AI industry’s most safety-focused lab has taken its most consequential step yet toward becoming a publicly traded company.
