Anthropic's S-1, in 10 Numbers

Anthropic made its IPO filing public on October 26, and for the first time the company behind Claude has shown its books. It plans to list on the Nasdaq Global Select Market under the ticker ANT, with Goldman Sachs and Morgan Stanley leading 22 underwriters.

Several numbers are still blank. The price range, the share count, third-quarter revenue and the total of Anthropic's compute commitments will arrive in an amended filing. What is already there runs to more than 300 pages. These are the 10 figures we pulled out, with the context the cards didn't have room for.

What surprised most readers of the S-1 was the sheer pace of growth. Anthropic's revenue was $41 million in 2023 and $386 million in 2024. In 2025 it reached $4.6 billion. In the first half of 2026 alone, it brought in $16.3 billion, up 1,300% from $1.2 billion a year earlier.

The quarterly line is steeper still. Revenue rose from about $0.4 billion in the first quarter of 2025 to $11.6 billion in the second quarter of 2026. Anthropic hasn't given third-quarter revenue in dollars, but says it was 86 times its revenue for the fourth quarter of 2024, which was $197 million. By that math, the quarter came to about $17 billion.

The filing is blunt about what comes next: "We do not expect our revenue will continue to grow at comparable rates, and we cannot assure you that it will continue to grow at all."

The quality of that growth is even more striking than its size. Net revenue retention compares what customers spent in the latest three months with what the same customers spent in the same three months a year earlier. For Anthropic, it was about 900% as of September 30. Existing customers, in other words, now spend roughly nine times what they did a year ago. The figure leaves out Claude Pro and Max subscribers, whose fixed monthly fees don't expand the same way.

Much of that expansion comes from agents. In the third quarter, Claude Enterprise users who didn't use Claude Code spent less than $75 a month on average. The top 5% of Claude Code users spent about 20 times that. Price helps too. Anthropic says Claude Opus 5.5 cut customers' cost per task by about 40% compared with Opus 5, and cheaper tasks led to more usage.

The growth isn't propped up by a handful of accounts, either. No single customer made up more than 10% of revenue in the first nine months of 2026. Customers outside the top five accounted for about 79% of third-quarter revenue, up from 64% in the first quarter. The top five together still made up about 25% of revenue over the nine months.

Look at the customers from another angle, and the picture holds. More than 11,900 customers now pay Anthropic at least $100,000 a year, up from about 20 at the end of 2023, about 200 at the end of 2024 and about 1,500 at the end of 2025. More than 1,900 pay at least $1 million, and about 250 pay at least $10 million.

Those customers include every company in the Fortune 10, more than half of the Fortune 500 and more than 30% of the Global 2000. Below them sits a long tail of about 40 million customers that each pay less than $100,000 a year.

Even so, the largest buyers have barely started. For Fortune 500 customers in the $100,000-plus group, Anthropic accounted for less than 0.1% of their total expenses last quarter.

Anthropic is just as striking on efficiency, and Claude itself is a big reason. In September, Claude wrote more than 90% of the contributions to Anthropic's own codebase. The average engineer now ships over 45 times as much code per day as in 2024, mostly by directing and reviewing Claude's work rather than writing code line by line.

The same goes for the models. The filing says each version of Claude now helps build the next, from running experiments and processing training data to writing and reviewing code. Anthropic calls this "closing the loop" and describes it as "one of the most significant structural advantages in frontier AI."

The result shows up in revenue per employee, which reached $6.6 million over the 12 months to September 30, up from $1.4 million a year earlier. Over that period, revenue grew about 1,200% while headcount grew about 170%. Anthropic now has about 5,300 employees, compared with about 940 at the end of 2024.

The sales side is lean as well. Sales, marketing and partnerships expenses came to 19% of revenue in the first half of 2026. Much of the selling runs through partners. Cloud marketplaces from Amazon, Google and Microsoft accounted for 48% of revenue in that period, and consulting firms such as Accenture, Deloitte, KPMG and PwC have built dedicated Claude practices.

Revenue per dollar of compute is a trickier number. It rose from $0.40 in the first quarter of 2025 to $2.08 in the second quarter of 2026. In the second quarter alone, revenue grew 1,368% year over year while compute and infrastructure costs grew 300%.

The catch is timing. Anthropic commits to compute well in advance but books the cost only as capacity comes online, "often in large, discrete steps." Revenue from that capacity follows later. The ratio can jump when revenue outruns new capacity and fall back when a large block arrives. The filing also expects more expensive short-term compute, bought when demand exceeds its long-term capacity, to "compress our operating margin" in the near term.

Securing that capacity has also required some complicated deals, with partners that are at once investors, suppliers and lenders. More on that below.

Those efficiencies have pushed Anthropic into profit on an operating basis. Its adjusted operating margin reached 19% in the second quarter. In the first quarter of 2025, it was minus 221%. The adjusted figure leaves out stock-based compensation, non-cash charitable contributions and the $1.5 billion Bartz copyright settlement.

The cost structure explains the turn. In the first half of 2025, compute and infrastructure costs were twice the size of revenue. A year later, they came to 55% of revenue, with personnel and sales and marketing at 19% each.

The $80.7 billion net loss for the first half has drawn the most headlines. It is closer to an optical illusion.

Most of it, $72.4 billion, comes mainly from convertible notes held by Amazon. Because the notes convert into shares, their value rises with Anthropic's valuation, and accounting rules require the company to book that increase as a loss. The more Anthropic is worth, the bigger the loss. The same item made up $34.3 billion of its $42 billion net loss in 2025. The filing says the notes will convert into stock around the IPO, subject to a cap on Amazon's ownership.

None of this is cash. Leaving out such items, adjusted net income was $2.7 billion in the first half. Operating activities brought in $3.9 billion, against an outflow of $1.5 billion a year earlier. As of June 30, Anthropic held $112.4 billion in cash and $19.3 billion in short-term investments.

The real long-term weight is compute. Across the seven deals with disclosed amounts, Anthropic has committed to about $637 billion. Broadcom accounts for $161.2 billion in equipment leases, SpaceXAI for up to $120.5 billion, Google for at least $114.5 billion and Amazon for at least $110 billion. Microsoft, Nscale and Lambda make up the rest.

The scale says something about how hard Anthropic has pushed to lock in capacity. The filing also explains why: "In the past, we have significantly underestimated our compute requirements, which left us capacity constrained and impacted both product development and deployment." Users felt it too. Anthropic has changed usage and rate limits at times, and the filing notes that some of those changes led to claims that its disclosures about model access or capabilities were "inadequate or misleading."

That total leaves out two deals without fixed prices. Additional Google TPU capacity is estimated at $125 billion to $150 billion, and AMD hardware at more than $20 billion. The filing says most of its commitments fall between 2031 and 2045.

The terms differ. The Google, Amazon and Microsoft contracts must be paid regardless of actual usage. The SpaceXAI deals, after initial periods ending in early 2027, can be cancelled by either side with 90 days' notice.

The filing names the mismatch itself: "our revenue is primarily consumption-based, and much of it is not subject to long-term contractual commitments, while our compute and infrastructure commitments generally extend over multiple years."

Anthropic's unusual structure carries over into the public company. It is a public benefit corporation, and its stock comes in five classes. Class A shares, the ones sold in the IPO, carry one vote each. A single share of Class F stock, held by an LLC of Anthropic's seven co-founders, carries 50.1% of the vote. A single Class T share, held by an independent Long-Term Benefit Trust, lets the trust elect a majority of the board. Amazon and Google hold nonvoting Class N shares, and employees hold Class E shares that vote only on limited matters.

The filing spells out what that means for public shareholders. Holders of Class A stock "generally will not be able to affect the outcome of any matter submitted to a vote." The founders' special vote starts to wind down only if fewer than three of them remain for 90 days in a row.

The structure also gives part of the company away. Anthropic contributed 5% of its fully diluted shares, about 847 million, to an Anthropic Public Benefit Fund, and can add up to 2% more each time its share price rises 50%. Each co-founder has also pledged to give away 80% of their personal equity, though the filing notes the pledges are not legally binding.

The amended filing, and the weeks after it, should answer a few open questions.