Anthropic's IPO Filing: What We Know and What Happens Next

Anthropic, the company behind the Claude AI models, opened its books to the public on Monday 26 October 2026. It filed a public Form S-1 with the US Securities and Exchange Commission for an initial public offering, and plans to list on the Nasdaq under the ticker ANT (NPR).

The prospectus does not yet say how many shares will be sold or at what price. Reports have put the expected valuation at between $1.5 trillion and $2 trillion, up from $965 billion at Anthropic's last private funding round in May. A listing could come as soon as November.

Here is what the filing reveals, what happens between now and the first trade, and the risks Anthropic itself has flagged to investors.

What the filing reveals

Anthropic's revenue is now growing far faster than its costs, but on paper it is still deeply loss-making. These are the headline figures from the Form S-1:

Revenue. First-half revenue of $16.3 billion is already more than three times the $4.6 billion Anthropic earned in all of 2025. In 2023, its first full year of selling Claude, revenue was $41 million. The filing says second-quarter revenue grew 1,368% year on year, while compute and infrastructure costs grew 300%.

The $80.7 billion loss. Most of it is not cash leaving the business. About $72.4 billion is an accounting charge for revaluing convertible notes, SAFEs and other instruments Anthropic used to raise money; as the company's valuation rose, so did the value of those instruments. The operating loss, which reflects the day-to-day business, was $693 million, about 4% of revenue. Anthropic recorded its first quarterly operating profit, $974 million, in the second quarter (Mostly Metrics).

Cash and customers. As of 30 June 2026 Anthropic held $131.7 billion in cash and short-term investments, and had raised $141.1 billion in total since its founding. By 30 September it had more than 11,900 customers spending at least $100,000 a year, more than 1,900 spending at least $1 million, and about 250 spending at least $10 million.

How the offering is structured

Investors will buy Class A shares on the Nasdaq Global Select Market under the symbol ANT. Anthropic will sell new shares, and some existing shareholders will sell part of their stakes in the same offering. The price range, share count and amount to be raised are still blank in the S-1. Goldman Sachs and Morgan Stanley lead a syndicate of 22 banks.

How big could it be? Reports put the target valuation at $1.5 trillion to $2 trillion (NPR). IPO specialists at IPOScoop expect the deal to raise about $75 billion, close to SpaceX's record June listing (IPOScoop). Others report that bankers have floated $100 billion or more (Mostly Metrics). Anthropic's last private price was a $965 billion post-money valuation in its May Series H round.

Who can buy. Besides the US, the offering includes public offerings in Australia, Canada, parts of the European Economic Area, Japan, Switzerland and the United Kingdom. Anthropic says it does not plan to list on any exchange in those countries. South Africa is not on the list.

Who controls the company. Buying ANT shares will give investors an economic stake but little say over how Anthropic is run. Anthropic is a public benefit corporation, which legally requires its board to balance shareholder returns against its stated purpose: "the responsible development and maintenance of advanced AI for the long-term benefit of humanity." Control is split across five share classes:

In practice, the Long-Term Benefit Trust, a body of five financially disinterested trustees, chooses most of the board, and the co-founders, led by CEO Dario Amodei and President Daniela Amodei, control the majority of shareholder votes. That makes Anthropic a "controlled company" under Nasdaq rules, so some standard governance requirements will not apply.

Built-in giving. Anthropic has placed 5% of its fully diluted shares, about 847 million shares, in a wholly owned Anthropic Public Benefit Fund. Its board may add up to a further 2% each time the share price rises 50% above the previous milestone, starting from the IPO price. Each co-founder has also pledged 80% of their personal equity to philanthropy.

Why Anthropic is listing now

Monday's filing is the public half of a process Anthropic started in June, and its timing has been shaped by its rivals as much as by its own growth.

A confidential filing let Anthropic work through the SEC's comments without exposing its finances. At the time, Anthropic said the step gave it "the option to go public after the SEC completes its review" (NPR). Analysts at Wedbush described the three filings from SpaceX, Anthropic and OpenAI as a race to reach public markets.

That race now has one fewer runner. In September Altman called a 2026 OpenAI listing ill-advised, citing growing concern over AI safety (NPR). If Anthropic lists in November, it will be the first of the big standalone AI model developers to trade on a public exchange.

The market backdrop is less calm than it was in June. SpaceX shares jumped after its debut but have since fallen back to about $150, roughly where they started trading. Data-centre operator CoreWeave's shares slumped in October over worries about how it will fund its expansion, and Intel, Meta and Nvidia have also slid. Georgetown University's Jim Angel told NPR that listing now makes sense to capture a high valuation, but warned that fears of an AI bubble could make trading volatile.

What happens next

If the reported timetable holds, Anthropic will start marketing its shares around 9 November and begin trading before the US Thanksgiving holiday on 26 November. Bloomberg first reported that plan on 1 October, and noted that the timing could still change (PYMNTS). Anthropic has not confirmed any dates. These are the steps between now and the first trade:

1. The numbers get filled in. Anthropic files an amended S-1 with a price range and the number of shares on offer. Revenue for the quarter to 30 September is also still blank; the Wall Street Journal reported that the November timing was chosen partly so Anthropic could show investors those figures.

2. The roadshow. Executives and bankers pitch the shares to large investors to gauge demand. Because Anthropic started with a confidential filing, SEC rules require the public S-1 to be out for at least 15 days first, which points to about 10 November at the earliest. IPOScoop, citing Bloomberg, reported that marketing could begin as soon as the week of 9 November (IPOScoop).

3. The SEC signs off. The commission declares the registration statement effective. Until then, no shares can be sold.

4. Pricing. Based on the orders collected, Anthropic and its banks set the final price and allocate shares, usually the evening before trading starts.

5. First trade. ANT opens on the Nasdaq Global Select Market. Anthropic has said that after listing it will publish material information through SEC filings, its investor relations page and its official social media accounts.

After the debut, the next dates to watch are the lock-up expiries, when early investors and employees become free to sell. All seven co-founders are named as selling stockholders in the offering itself, although the number of shares each plans to sell has not yet been disclosed (Mostly Metrics).

The risks Anthropic is flagging

The risk factors section of the S-1 runs to almost 100 pages. These are the issues most likely to shape how investors price the deal.

• Compute costs and commitments. Anthropic rents most of its computing power from Amazon, Google and Microsoft, which also invest in Anthropic and sell rival AI models. The filing warns that these providers could cut, reprice or end that supply, and admits they have previously declined to provide as much capacity as Anthropic wanted. The total of its long-term compute commitments, which run as far as 2045, is left blank. Reuters, reviewing an earlier draft, put projected spending on cloud, computing and infrastructure at $518 billion (PYMNTS).

• Reliance on cloud marketplaces. No single customer accounts for more than 10% of revenue, but 48% of first-half revenue came through the AWS, Google Cloud and Azure marketplaces (Mostly Metrics).

• Slowing growth and rising share-based pay. Anthropic expects its growth rate to fall. Once it lists, it must also start expensing restricted stock units that only vest on an IPO: about $2.9 billion immediately and $23.7 billion over roughly two years. Mostly Metrics' analysis suggests that could push Anthropic back to a GAAP operating loss until revenue catches up.

• Safety and misuse. The filing warns that Claude could be misused by bad actors, or could act in unintended or harmful ways that no user directed. It also says Anthropic's capabilities could advance faster than its safety work, and that precautions such as delaying model releases could cost it ground against competitors.

• Politics and the Pentagon. Anthropic flags the risk of political backlash over its views on AI policy and regulation. Earlier this year the Pentagon designated it a "supply chain risk" after a dispute over military use of its models; Anthropic has sued in two federal courts and those cases are ongoing (NPR).

• Copyright. Anthropic paid $1.5 billion in 2025 to settle the Bartz case over books used in training. It warns that court rulings against other AI companies on fair use could set precedents that also affect its business.

• Limited shareholder say. The filing states plainly that its structure may leave Class A shareholders effectively unable to influence major decisions, including a takeover, and that its public benefit duties may sometimes conflict with financial returns.

Dates to watch

• Early November: an amended S-1 with the price range, share count and, possibly, third-quarter results.

• Week of 9 November: reported earliest start of the roadshow.

• Before 26 November: reported target for pricing and the first trade under ANT.

• After the listing: lock-up expiries for insiders and early investors.

Blockrora will update this piece as the price range and listing date are confirmed.

This article reflects information available as of 1 November 2026. Figures come from Anthropic's preliminary prospectus and press reports, and may change in later filings. Nothing here is financial advice.