Anthropic S-1 Analysis: How 7 Key Metrics Stack Up

Anthropic filed their S-1¹ this week, the largest AI listing yet.

Founded in 2021 by Dario & Daniela Amodei, the company has grown from a research lab into the second-largest model developer, selling Claude to more than 11,900 customers who spend over $100,000 a year. The comparisons below set the reported OpenAI figures² against Anthropic’s derived gross margin³, adjusted operating margin⁴ & compute commitments⁵.

Anthropic generated $16.3B of revenue in the first six months of 2026, a fourteen-fold increase over the $1.2B of the first half of 2025. That half-year alone was more than three times all of 2025, when Anthropic grew 11.9-fold to $4.6B, more than four times OpenAI’s 253%.

The second quarter was $11.6B against $4.7B in the first; revenue has nearly tripled for two consecutive quarters.

Three straight years of roughly ten-fold growth: 9.4x, then 11.9x, then 14.0x.

For example, with the release of Claude Fable 5.1 in September 2026, we reduced the cost of typical workloads by approximately 25% compared to Fable 5, with savings of up to 45% for complex coding & highly agentic tasks. Similarly, with the release of Opus 5.5 that same month, we reduced customers’ cost per task by approximately 40% compared to Opus 5.

When Opus 4.5 launched in November 2025 with more capability & a lower cost per task than Opus 4.1, revenue growth accelerated from 48% quarter over quarter to 132% the following quarter. Jevon’s paradox in the real world.

Anthropic is cash-flow positive. Operating loss was $8.1B in 2025 including a $1.5B copyright settlement. It narrowed every quarter of 2026, & in the second quarter Anthropic reported $974M of operating income, an 8.4% GAAP margin & 19% adjusted.

Anthropic has distributed its computing needs evenly over four major providers. Broadcom, SpaceXAI, Google & AWS each hold between $110B & $161B of commitments, together four fifths of the $637B total.

Anthropic carries essentially no drawn debt : the $15B revolver is undrawn & the only outstanding notes are $6.2B of non-interest-bearing Amazon convertibles. The leverage is instead in commitments. The filing discloses $265.6B of fixed or minimum guarantees at June 30, 2026 & a further $245B executed since.

These businesses are forming a keiretsu : each entangled in the other’s equity, debt & go-to-market.

Concentration has fallen : no single customer exceeded 10% of revenue for the nine months to September 30, 2026, & the top five were about 25%. That is different from 2025, when customers spending over $100,000 accounted for 76% of revenue.

This pattern of initial deployment, demonstrated value, & rapid expansion has been replicated across organizations & is reflected in our Net Revenue Retention of approximately 900% as of September 30, 2026.

What is Anthropic worth? The case for a very large number is simple : a business that grew 11.9-fold on a 40% derived gross margin & has just begun earning an operating profit. The case against is equally simple : $637B of compute commitments, two thirds non-cancelable, against $4.6B of 2025 revenue, where revenue is consumption-based with no lock-in & the payments arrive whether customers do.

Nearly half of Anthropic revenue is now delivered through market places, a natural progression of many enterprise companies.

Anthropic’s S-1 describes an AI company with an enviable business model, explosive growth, & increasing efficiency.

Congratulations to the Anthropic team on reaching this milestone. Building a business that went from $41M to a $16B half-year in three years is without precedent.

1. Anthropic, PBC Form S-1, SEC EDGAR CIK 0002130357, accession 000162828026067168, filed October 26, 2026: https://www.sec.gov/Archives/edgar/data/2130357/000162828026067168/anthropicpbc-sx1.htm ↩︎

2. OpenAI figures are press-reported & unverified. Anthropic figures are from the S-1 filed October 26, 2026 (SEC EDGAR CIK 0002130357). ↩︎

3. Anthropic does not report gross margin. It changed in FY2025 from a functional presentation to one by nature of expense. The 40% is derived from Note 8, which retains cost of revenue: (4,585 - 2,773) / 4,585. The equivalent for the first half of 2026 is 85%: (16,286 - 2,380) / 16,286. Both are my calculations, not disclosed figures. ↩︎

4. Adjusted operating income excludes stock-based compensation, non-cash charitable contributions & the Bartz settlement. FY2025 adjusted operating loss was $4.9B against a GAAP $8.1B. ↩︎

5. The $637B of commitments is the sum of seven named agreements in the filing: Broadcom $161.2B, SpaceXAI up to $120.5B, Google at least $114.5B, Amazon at least $110.0B, Microsoft at least $44.9B, Nscale up to $44.6B & Lambda approximately $41.3B. The filing does not disclose an aggregate total; that figure is my arithmetic. Google, Amazon, Microsoft & Broadcom are “at least” commitments that are non-cancelable with true-up clauses. SpaceXAI may be cancelled by either party on 90 days’ notice after initial periods ending January & March 2027. Nscale & Lambda accrue fees only as capacity is delivered. ↩︎