SAN FRANCISCO — Anthropic told prospective investors this week that its revenue reached $16.8bn in the third quarter, more than three and a half times what it booked in the first, as the maker of the Claude chatbot prepares for what could be one of the largest stock market listings on record.

The figure, presented at a closed investor day at the company's San Francisco headquarters on Wednesday, was up 45% from $11.6bn in the second quarter and compares with $4.7bn in the first, Reuters reported, citing two attendees. The Financial Times first reported the number. Bloomberg gave the same figure, citing people familiar with the matter.

The disclosure matters beyond one company. Anthropic's listing is expected to come before that of rival OpenAI, making it an early test of investor appetite for loss-making AI developers that are spending heavily to reach vast scale, Reuters reported.

The pace of growth has slowed, however, and that has cooled some expectations. Some current and prospective investors who attended the event are now discussing a valuation of about $1.5tn for the November share sale, below the roughly $2tn they had expected, Reuters reported on Thursday. Revenue had more than doubled between the first and second quarters, and some investors were disappointed by the smaller gain that followed.

Other prospective buyers put Anthropic's fair value at $1.8tn to $2tn, according to Bloomberg. The company has not published a price range. Even the lower figure would be far above the $965bn valuation Anthropic set when it raised $65bn from private investors in May.

The company also told investors it was profitable on an adjusted basis in the quarter. Bloomberg, citing people familiar with the matter, reported a gross margin of 85% and an adjusted operating margin of more than 11%, and the FT said the company told investors it was cash-flow positive. The reports did not say which costs the adjusted measures leave out, and Anthropic has not released audited quarterly accounts. It declined to comment to Bloomberg.

Anthropic was founded in 2021 by former OpenAI executives, including chief executive Dario Amodei. It sells access to its Claude models to businesses and software developers and through a consumer chat app.

Its finances have changed quickly. Revenue rose twelvefold in 2025 to nearly $4.6bn, according to Reuters, while the company lost more than $8bn on an operating basis, excluding writedowns tied mostly to earlier fundraising. Analysts estimate that its annualised revenue run rate could reach $110bn by the end of this year, the news agency reported.

Its spending commitments are also vast. Anthropic has committed at least $518bn over a decade for cloud services, computing and infrastructure, according to Reuters. Amazon and Alphabet's Google are both investors and suppliers of computing power, as well as distribution partners and competitors in AI.

Those two companies have a direct stake in the final price. Amazon's second-quarter profit included $53.4bn of pre-tax non-operating income, mainly from Anthropic, according to an analysis by 24/7 Wall St. published on Yahoo Finance. Neither company discloses the carrying value of its holding.

Investors met Amodei and chief financial officer Krishna Rao at Wednesday's event, where attendees were handed caps, some printed with the word "thinking", Reuters reported. One attendee said Amodei repeated the company's focus on AI safety but did not raise the threat of human extinction. In a prospectus seen by Reuters in September, Anthropic warned that advanced AI could pose "catastrophic or existential risks to humanity."

That warning has drawn pressure from at least one public investor. In a letter to Amodei dated Oct. 14, the day of the investor event, New York City Comptroller Mark Levine urged the company to pause its listing. "Instead of proceeding headlong with its IPO, the company should focus its energies on addressing these unprecedented risks," wrote Levine, who acts as investment adviser to city pension funds holding more than $325bn.

Levine cited a Sept. 12 essay in which Amodei argued that the pace of improvement in AI capabilities must slow. He asked Anthropic to set out how it would carry out audits and controls, what they would cover and on what timeline.

The valuation debate comes as investors reassess the economics of the sector's other giant. OpenAI is seeking about $30bn in new funding at a valuation of around $1.4tn and has pushed its own listing to early 2027, Bloomberg reported. The FT reported that investors had cut their estimate of OpenAI's annualised revenue to about $50bn from $70bn. Shares and bonds of the AI cloud provider CoreWeave fell on Thursday during a wider technology sell-off.

Anthropic filed confidentially for a US listing on June 1. Formal marketing to investors could begin as early as the week of Nov. 9, with trading to start before the Thanksgiving holiday on Nov. 26, according to Bloomberg, which said the plans remain fluid. Under Securities and Exchange Commission procedures, a company that files confidentially must make its registration statement public at least 15 days before its roadshow begins, which would put a public filing in late October if that timetable holds.