Anthropic files for an IPO, with its price and size still blank

On October 26, 2026, Anthropic, PBC filed a registration statement on Form S-1 with the U.S. Securities and Exchange Commission. An S-1 registers shares a company plans to sell to the public. Anthropic announced the filing the same day. The SEC's filing list also shows six earlier confidential drafts, from June 1 to October 9, 2026. Everything below comes from the S-1 unless I mark it as my reading.

What is being offered

Anthropic and some existing shareholders will both sell Class A common stock. The company has applied to list it on the Nasdaq Global Select Market under the symbol "ANT". Anthropic intends to use its proceeds for "general corporate purposes", including compute and infrastructure.

The numbers it reports

Millions of US dollars, from the summary statements of operations.

In the first half of 2026, 72,388 million dollars of the net loss came from revaluing convertible notes and related instruments. The filing says this was "primarily driven by an increase in the fair value of our outstanding convertible promissory notes resulting from an increase in our enterprise valuation". The notes can turn into shares. When the company is valued higher, the notes are worth more, and the company books that rise as a loss.

That charge used no cash. Operating activities brought in 3,929 million dollars in the first half of 2026, after using 1,513 million dollars a year earlier. The filing credits a smaller loss once non-cash items are set aside, and the timing of payments to vendors and cash receipts from customers. Financing activities brought in far more, 110,774 million dollars, in the same six months. As of June 30, 2026, Anthropic reported 112.4 billion dollars in cash and cash equivalents and 19.3 billion dollars in short-term investments.

The compute bill

Four of the compute arrangements described in the filing are: - Microsoft. At least 44.9 billion dollars between November 2026 and May 2033, "regardless of actual usage". - Google. At least about 114.5 billion dollars between April 2026 and July 2033. Anthropic also estimates 125.0 to 150.0 billion dollars for more TPU capacity in 2028 to 2031, which it has committed to but leaves out of its commitments table. - Amazon. At least 110.0 billion dollars between May 2026 and April 2036. - SpaceXAI, a SpaceX subsidiary. Up to 120.5 billion dollars into 2029. After initial periods ending in early 2027, either side may cancel on 90 days' notice.

The filing describes more, including GPU deals with Nscale and Lambda, an AMD hardware agreement and equipment leases with Broadcom. The total of all commitments is left blank in this version.

Who will control the company

Anthropic is a public benefit corporation. Its stated purpose is "the responsible development and maintenance of advanced AI for the long-term benefit of humanity."

Two bodies hold control: - The Long-Term Benefit Trust. It is meant as an independent body of five financially disinterested trustees. Through one Class T share, it generally elects and removes a majority of the board. - The co-founders. A company owned by the seven co-founders will hold one Class F share. That share alone carries 50.1% of the total voting power on general matters. The co-founders' total voting power, counting their other shares, is blank in the filing.

Each Class A share has one vote. Class N shares, held mainly by strategic partners, have none. The filing's risk summary says this structure "may effectively eliminate the ability of holders of our Class A common stock to influence important decisions, including a change in control."

Risks for ordinary readers

• A few large customers. No customer passed 10% of revenue in the nine months ended September 30, 2026, but the top five made up about 25%.
• Revenue from policy breaches. Anthropic estimates that 5% to 7% of its revenue in that period came from customers breaking its usage policy or terms.
• The US government. In February 2026, the President said he had directed all federal executive agencies to stop using Anthropic's technology. At the same time, the Secretary of War directed the Department of War to designate Anthropic a "supply-chain risk to national security". The filing links both to Anthropic's position that its technology should not be used for mass domestic surveillance or fully autonomous weapons. A district court ruled largely for Anthropic on August 27, 2026. On September 25, 2026, an appeals panel ruled 2-1 that one designation was proper. Anthropic has asked the full court to rehear the case.
• Copyright. The Bartz class action was settled for 1.5 billion dollars, with court approval in July 2026.

My reading

This is my interpretation, built on the linked passages.

Control stays with the trust and the founders. Directors must balance shareholders' money, the people the company affects and its purpose. The filing warns this duty may conflict with short-, medium-, or long-term financial interests. The board, not an outside body, sets how public benefit is judged, without being required to use an objective third-party standard. Ordinary shareholders have little routine control. Their separate approval does matter for some changes to the trust that the trustees do not back.

Release limits can cost growth, and the filing says so. Anthropic has delayed or limited model releases before. It warns that such measures could slow our capability gains relative to competitors. Public benefit decisions, such as giving shares to its Public Benefit Fund, could also contribute to dilution.

Minimum compute payments can outlast demand. My arithmetic: the three minimum commitments to Microsoft, Google and Amazon add up to about 269 billion dollars. In the first half of 2026, compute and infrastructure cost 8,945 million dollars against 16,286 million in revenue. The filing says its compute commitments are substantial and generally must be satisfied whatever revenue does. The same three cloud companies have made significant equity investments in Anthropic, buy from it, and compete with it. The notes still outstanding on June 30, 2026 were all issued to Amazon, with 6.2 billion dollars of principal. Their terms convert them into non-voting Class N shares, at the offering or in later quarters if Amazon's ownership cap holds part back, though they may also be settled in cash at maturity. The filing says such conversions will dilute the economic interests of Class A holders. My hypothesis: most of the paper loss ends as dilution, not as a cash bill. The larger cash risk is slower demand meeting fixed obligations.

Listing changes what outsiders can check. The 2023 to 2025 statements are audited. The first-half 2026 figures are unaudited, and metrics such as customer counts have not been independently verified by third parties. After the offering, Anthropic becomes subject to the reporting requirements of the Exchange Act. I think that record will matter more than this one document.

What I will watch: - An amended S-1 with the price range, share count and revenue for the quarter ended September 30, 2026, all blank now. - Lock-ups, the periods when insiders agree not to sell. The founders and certain holders above 0.5% may not sell until after results for the quarter ending September 30, 2027, or 365 days, whichever comes first. Other covered holders wait until after results for the quarter ending March 31, 2027, or 180 days. Holders above 0.5% and the other covered holders get staged early releases. Each founder may sell up to 29% of covered shares from the earlier of two moments: the second full trading day after the first-quarter 2027 results are released, or the close of trading on day 180 after the prospectus date. The underwriters' representatives may release shares early at any time. - The full appeals court's answer on the supply-chain designation. - The first quarterly report after listing.

Sources

• filing Anthropic, PBC Form S-1 registration statement (SEC EDGAR, filed October 26, 2026) (archived copy)
• data Anthropic, PBC filing list (SEC EDGAR, CIK 0002130357) (archived copy)
• release Anthropic files S-1 with the SEC for proposed initial public offering (Anthropic, October 26, 2026) (archived copy)