Anthropic raises $65B at a $965B valuation and files for IPO — in the same week
Anthropic closed a $65 billion Series H at a $965 billion post-money valuation on May 28 — surpassing OpenAI for the first time — then filed a confidential S-1 with the SEC four days later. Here are the numbers, the investor list, and the open questions ahead of the public prospectus.
In five days at the end of May 2026, Anthropic completed what amounts to the most consequential week in its history: a record-breaking private fundraise and the formal start of the path to a public listing.
The Series H: $65 billion, 27 lead and co-investors, a $15B infrastructure slug
On May 28, Anthropic closed a $65 billion Series H round at a $965 billion post-money valuation, surpassing OpenAI's $852 billion post-money mark from its $122 billion round in March.1
The round was co-led by Altimeter Capital, Dragoneer, Greenoaks, Sequoia Capital, Capital Group, Coatue, and D1 Capital Partners. Institutional names including Baillie Gifford, Blackstone, Brookfield, D.E. Shaw Ventures, DST Global, and Fidelity Management & Research joined as participants. Strategic infrastructure partners — Samsung, SK Hynix, and Micron — also took positions.1
$15 billion of the total represents previously committed capital from hyperscalers, including a $5 billion tranche from Amazon announced in April.1 Anthropic said the new capital will go toward safety and interpretability research, compute expansion, and scaling enterprise products.
Brad Gerstner of Altimeter summarized the investor thesis plainly: "Claude's latest advancements have driven large-scale adoption among the world's most demanding organizations. This momentum positions Anthropic to lead the next phase of AI innovation and capture the enormous opportunity ahead."1
The revenue context behind the valuation
The $965 billion figure is not floating on hype alone. Anthropic reported that its revenue run-rate crossed $47 billion earlier in May, up from $9 billion at end-2025 — a 5× climb in roughly five months.2 The Wall Street Journal separately reported that the company expects a 130% revenue surge to push it into its first operating profit.
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The growth driver is enterprise Claude Code adoption. The same day the Series H closed, Anthropic also released Claude Opus 4.8, its most capable agentic coding model to date.1
Also on May 19, nine days before the Series H closed, Anthropic hired Andrej Karpathy — OpenAI's co-founder and former Tesla AI lead — to build a team focused on using Claude to accelerate pre-training research itself.3 The hire signals that Anthropic believes AI-assisted research, not raw compute alone, is its competitive edge going into the public markets.
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The IPO filing: four days later
On June 1, Anthropic confidentially submitted a draft Form S-1 registration statement to the SEC — the first major AI lab to do so.42
The filing is confidential: no share count, no price range, no detailed financials in the public domain yet. The company said the IPO "will depend on market conditions and other factors." Once the SEC completes its review, Anthropic can choose to proceed or hold. Typically, a confidential S-1 becomes public two weeks before a roadshow.
The move puts Anthropic in a tight race with OpenAI — which is expected to file its own S-1 — and into the same IPO season as SpaceX, which is targeting a $2 trillion valuation on roughly $75 billion in expected proceeds.2 Wedbush analysts wrote that the Anthropic filing "represents a major step... to get ahead of OpenAI as Altman & Co. get ready to go through their own confidential filing."
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What this filing won't yet tell investors
Until the public S-1 drops, several material unknowns remain open:
- Ownership structure: Anthropic is a Public Benefit Corporation. How much voting control the Amodei family retains, and what governance rights institutional investors secured in earlier rounds, will only become clear in the prospectus.
- Mythos model commercialization: The Mythos cybersecurity model has been kept in restricted preview since April due to potential misuse risks. Bloomberg reported June 1 that the EU's cybersecurity agency is set to receive access.2 Wider deployment could materially change revenue trajectory before the IPO.
- SpaceX compute contract exposure: Anthropic's deal for roughly 220,000 GPUs through Colossus 1 at approximately $1.25 billion per month runs through May 2029. That concentrated compute dependency will likely be a focal point for S-1 risk-factor disclosures.
What to watch next
The SEC review clock starts now. If Anthropic moves at normal pace, a public prospectus could appear by late summer 2026, with a potential roadshow in Q3 or Q4. Any material change — a competing OpenAI filing, a Mythos incident, or a revenue miss — could shift that timeline. This channel will flag each development as it breaks.
Sources: TechCrunch, Anthropic official announcement, Bloomberg, The Wall Street Journal, Reuters.
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