Anthropic's S-1: an $80.7 billion loss that's mostly on paper, and one share with 50.1% of the vote

Anthropic made its IPO filing public this morning. The company behind Claude filed a Form S-1 with the SEC on October 26, 2026, and says it plans to list its Class A shares on the Nasdaq Global Select Market under the ticker "ANT." The number of shares and the price range haven't been set. Goldman Sachs and Morgan Stanley lead a long list of banks. On Hacker News, the filing drew more than 500 comments within about an hour.

We read the prospectus itself. Here is what's in it, and what the headlines skip.

The growth. Revenue was $16.3 billion in the six months to June 30, 2026, up from $1.2 billion a year earlier. Full-year revenue was $41 million in 2023, $386 million in 2024 and $4.6 billion in 2025. Anthropic says it does not expect growth to continue at this rate.

The loss, line by line. The headline number is an $80.7 billion net loss for those six months. Most of it isn't money that left the building:

Operating loss: $693 million, down from $2.1 billion a year earlier. Revenue nearly covered operating costs of $17.0 billion.
Compute and infrastructure: $8.9 billion, the biggest single cost. Sales, marketing and partnerships jumped from $120 million to $3.2 billion.
$72.4 billion is a "change in fair value of convertible notes, derivative liabilities, and SAFEs." 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." Put simply, the more Anthropic was worth, the more it owed note holders on paper, and that counts as a loss.
Another $8.8 billion of other expense, mostly changes in the value of investments and other financial instruments.
Anthropic's own non-GAAP measure, "Adjusted Net Income," was a $2.7 billion profit for the half. That's the company's definition, which removes stock pay, those fair-value changes and a few other items.

The customers. No single customer made up more than 10% of revenue in the nine months to September 30, 2026, but the top five made up about 25%. Anthropic reports more than 11,900 customers paying $100,000 or more a year (up from more than 950 a year earlier), more than 1,900 paying $1 million or more, and about 250 paying $10 million or more. It had $131.7 billion in cash and short-term investments on June 30.

The votes. This is the part to read twice:

Class F: one share. Right before the IPO, Anthropic will issue a single Class F share to an LLC owned by its seven co-founders, including CEO Dario Amodei and President Daniela Amodei. That share carries 50.1% of the total voting power on matters put to stockholders, including electing the directors the trust doesn't pick. It has no economic rights. The filing says this lets the Founder LLC decide "all matters submitted to a vote of our stockholders generally," including a merger or sale, "for the foreseeable future." It stays until fewer than three founders remain for 90 days, plus a transition period, or until it's redeemed.
Class T: the trust. Anthropic's Long-Term Benefit Trust, a body of "financially disinterested" trustees, elects and removes the directors who make up a majority of the board.
Class A: the public. IPO buyers get one vote per share. Anthropic is a public benefit corporation, so the board must weigh its stated purpose, "the responsible development and maintenance of advanced AI for the long-term benefit of humanity," alongside shareholder returns. It will be a "controlled company" under Nasdaq rules.
Anthropic also put 846.8 million Class N shares, 5% of the fully diluted count, into its own Public Benefit Fund, with more issued each time the stock rises 50% above the last milestone. The co-founders have each pledged 80% of their personal equity to philanthropy.

The risks it names. The filing says advanced AI could "pose catastrophic or existential risks to humanity," and that no single insurer, and maybe not the whole insurance industry, could cover a catastrophic AI incident. It also discloses that in June 2026 the U.S. Commerce Department put worldwide export restrictions on its Fable 5 and Mythos 5 models. Anthropic disabled them for all customers until the restrictions were lifted after it updated its safeguards.

Our take

The $80.7 billion loss is real accounting, but most of it is a side effect of Anthropic getting more valuable. That doesn't make the business cheap to run: compute alone was $8.9 billion in six months, and five customers bring in about a quarter of revenue. For anyone buying in, the bigger fact is control. Public shareholders will own the economics, but a single founder share plus a trust that picks most of the board will decide almost everything. Anyone who builds on Claude now depends on a company that will report every quarter, which brings more disclosure and more pressure on pricing and margins.

What we did and didn't do: we read the S-1 on SEC EDGAR and Anthropic's announcement on October 26, 2026. Blanks in the filing (offering size, price range, post-IPO voting percentages) were still unfilled. Valuation figures reported elsewhere aren't in the filing and aren't used here. Not investment advice. Not sponsored; no affiliate links.

MODEL Editors