Anthropic added $5.4 billion of revenue in the third quarter of 2026, $1.4 billion less than the $6.8 billion it added in the second, by our arithmetic from the quarterly table in its amended Form S-1 filed with the SEC on 2 November. Growth on the prior quarter fell from 144.2% to 46.7%.
Both measures slowed. The test comes from a newsletter post, “Anthropic’s growth just flattened”, by Henry Blodget’s Regenerator, dated 15 October and posted to Hacker News on 2 November. The filing confirms its dollar claim; it has no monthly figures to test the rest.
Business Pill · Run-Rate Revenue
An evergreen Business Engineer explainer on run-rate revenue: what an annualised figure measures and what it does not. It explains the general idea only and does not discuss this filing.
The key insight: On the S-1/A’s quarterly table, both measures of Anthropic’s growth slowed in the third quarter: dollars added fell to $5,401 million from $6,824 million, and growth on the prior quarter fell to 46.7% from 144.2%, by our arithmetic. Adding back the filing’s approximately $600 million of price reductions still leaves the gain below the second quarter’s.
The post worked from revenue figures reported before the filing: $4.8 billion for the first quarter, $11.6 billion for the second and $16.8 billion for the third. It wrote that “Anthropic’s sequential revenuegrowth in Q3, moreover, was smaller in absolute dollars than its (gobsmacking) growth in Q2”.
It then made what it called “back-of-the-envelope estimates” of monthly revenue, adding a reported $65 billion annualized run rate for July, which it said “equates to ~$5.4 billion of July revenue”. On that basis it wrote that “it seems Anthropic barely grew from July to September”. It offered seasonality, Anthropic being unable to keep up with demand, and moderating AI spending growth as possible explanations.
Anthropic revenue added on the prior quarter (bars, $ billions) and quarter-on-quarter growth (line, %), Q2 2025 to Q3 2026. Dollar adds and growth rates are our arithmetic from the unaudited quarterly table in the S-1/A of 2 November 2026.Animated: revenue Anthropic added on the prior quarter, Q2 2025 to Q3 2026, in $ billions: 0.41, 0.60, 0.66, 2.69, 6.82 and 5.40. Our arithmetic from the unaudited quarterly table in the S-1/A of 2 November 2026. Not a forecast.
What the Filing’s Quarterly Table Shows
The S-1/A gives unaudited revenue for seven quarters: $376 million, $787 million, $1,382 million, $2,040 million, $4,731 million, $11,555 million and $16,956 million, from the first quarter of 2025 to the third quarter of 2026. It says “Revenue increased sequentially in each of the quarters presented”.
The dollars added on each prior quarter were $411 million, $595 million, $658 million, $2,691 million, $6,824 million and $5,401 million, by our arithmetic. The third-quarter add is the first of the six to be smaller than the one before it: $1,423 million, or 20.9%, below the second quarter’s.
Growth on the prior quarter ran 109.3%, 75.6%, 47.6%, 131.9%, 144.2% and 46.7%, by our arithmetic. The third quarter’s 46.7% is the lowest of the six, just below the 47.6% of the fourth quarter of 2025; after that quarter the rate rose to 131.9% and then 144.2%.
The slowdown is from a large base. The third-quarter add alone was larger than Anthropic’s whole 2025 revenue of $4,585 million, and it is the second-largest add in the table, by our arithmetic.
Testing Each Claim
Smaller dollar gain in Q3: confirmed. On the filing’s figures the gain fell from $6,824 million to $5,401 million. The newsletter’s pre-filing figures gave $6.8 billion and $5.2 billion; the filing’s third quarter is $156 million higher than the $16.8 billion the post used, so its Q3 gain is about $0.2 billion larger, by our arithmetic.
Slower growth rate: confirmed. The post gave 141% and 45%; the filing’s figures give 144.2% and 46.7%, a fall of about 97 percentage points, by our arithmetic.
Flat from July to September: not testable from the filing. The S-1/A reports quarters, not months, by our search of its full text. It defines Run-Rate Revenue as consumption-based fees for a trailing 28-day period multiplied by 13, plus monthly subscription fees multiplied by 12, so dividing a run rate by 12 is the post’s own conversion, not the filing’s. The filing gives no July figure, and its one dated Run-Rate Revenue sentence, as of 31 October 2026, leaves the dollar amount blank.
What the Filing Says Moved in the Quarter
The filing names one quantified drag on the third-quarter increase. From the second to the third quarter, “the increase in revenue due to higher usage was partially offset by a decrease of approximately $600 million from price reductions introduced as part of new model versions and contractual discounts”.
Adding that $600 million back gives a usage-driven increase of about $6.0 billion, still about $0.8 billion below the second quarter’s $6.8 billion, by our arithmetic. The filing says “Price changes did not have a material impact on the other quarterly revenue trends presented”, apart from about $70 million in the fourth quarter of 2025.
It also flags two factors without putting a number on their effect in the quarter. On enforcement, it says that “the enhancement of such efforts in August and September 2026” against customers using its models in violation of its usage policy or commercial terms may reduce overall revenue and growth rates in future periods. It estimates revenue from such customers at “approximately 5% to 7% of our revenue for the nine months ended September 30, 2026”.
On seasonality, it says Anthropic has experienced “lower usage around holiday and vacation periods in the summer and winter, when certain customer workflows slow down and overall customer activity declines”, and that “Our historical growth rates may have masked the impact of seasonal trends on our results”.
On the cost side, compute and infrastructure rose from 48% of revenue in the second quarter to 58% in the third, in the filing’s percentage table. The filing says “This includes $5.0 billion of compute under short-term commitments, which currently costs significantly more than comparable compute procured under our multi-year commitments”. Its outlook line is “We expect our revenuegrowth rate to decline over time and to fluctuate from period to period”.
As we read the table, the two measures tell different parts of the story: a 46.7% rise on a $11.6 billion base still added more revenue than Anthropic booked in all of 2025, yet it was the first quarterly gain in the filing to come in below the one before.
As we read the filing, it gives a number for one drag on the quarter, the approximately $600 million of price reductions, and words without numbers for others, including enforcement against policy-violating customers in August and September and summer seasonality. The monthly path the newsletter estimated is not in the filing.
Anthropic PBC, Form S-1/A, 2 Nov 2026
“We expect our revenuegrowth rate to decline over time and to fluctuate from period to period”
Three Implications
FOR THE GROWTH DEBATE The filing confirms the newsletter’s dollar claim: the third-quarter gain of $5,401 million was below the second quarter’s $6,824 million, by our arithmetic.
FOR PRICING The filing says price reductions from new model versions and contractual discounts offset the third-quarter increase by approximately $600 million.
FOR THE RUN RATE The filing defines Run-Rate Revenue on a trailing 28-day basis and leaves its 31 October figure blank, so the newsletter’s July-to-September monthly path cannot be checked against it.
The framework reads: “The reason cheaper tokens produce bigger bills is structural”.
As we read it, Anthropic’s third quarter shows both sides of that line in one filing: approximately $600 million of revenue given up to price reductions, set against a usage-driven increase of about $6.0 billion, by our arithmetic. The framework was published in June 2026 and does not discuss Anthropic’s quarterly results.
The filing gives no monthly revenue, so whether growth stalled in August and September, as the newsletter estimated, cannot be checked against it. We did not verify the $65 billion July run rate the post cited, and the filing’s 31 October Run-Rate Revenue figure is blank. The filing does not say how much of the slowdown came from enforcement, seasonality or capacity. The post’s link to neocloud stocks was not tested. We did not contact Anthropic or the author.
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On the S-1/A’s quarterly table, Anthropic’s third-quarter revenue gain fell to $5.4 billion from $6.8 billion and growth on the prior quarter fell to 46.7% from 144.2%, by our arithmetic, which matches the newsletter’s dollar claim. Even with the $600 million of price reductions added back, the gain was below the second quarter’s.
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A note on sourcing. Filing figures and quotes are from Anthropic’s SEC Form S-1/A of 2 November 2026; its quarterly figures are unaudited. The newsletter’s figures and quotes are from its post of 15 October. Dollar adds, growth rates, the usage-driven $6.0 billion and all comparisons are our arithmetic.
Gennaro Cuofano is a CRO and tech executive who has worked in AI since late 2015, starting with bringing NLP, natural-language generation, voice and chatbot products to the marketing industry. His background is in law and finance: he holds a Master's degree in Law and an International MBA with an emphasis on corporate finance (LUISS Business School and the University of San Diego, 2012), and worked as a financial analyst at a real-estate investment firm in San Diego and as an assistant controller. His work focuses on business model strategy, business engineering and, more broadly, structural analysis: how companies make money, read from their own filings. He created FourWeekMBA and leads research there and at The Business Engineer, his newsletter on AI and business strategy, with over 95,000 subscribers and more than 1,000 published analyses. His writing has also appeared on Entrepreneur (for example, How to Digitize a Family Business in Europe) and HackerNoon. Find him on LinkedIn and Substack. See how we source.
