Anthropic last year depended upon only two cloud providers, Amazon and Google, for 47 percent of its sales to customers last year, the company said in its confidential IPO prospectus, according to a Reuters report.

The same two companies, which are also collecting customer bills, are both major Anthropic investors, in addition to being direct Anthropic competitors, highlighting the circular dependence of Anthropic’s business on a small group of firms.

Revenue rose 12-fold in 2025 to nearly $4.6 billion (£3.5bn), with operating losses more than doubling to more than $8bn, with the US accounting for nearly two-thirds of sales, according to an earlier report.

Market concentration

About $3.8bn of Anthropic’s revenues came from usage-based billing, with subscription revenues amounting to $789m, according to the prospectus.

Anthropic said it expects usage-based revenue to account for the “substantial majority” of its income for the foreseeable future.

Sales through cloud marketplaces accounted for about $2.16bn, or 47 percent of Anthropic’s 2025 annual revenue, according to the filing.

Anthropic paid about $351m back to the platforms in the form of distribution fees, suggesting that cloud providers are taking about 16 percent of those sales, Reuters’ analysis found.

In the filing, Anthropic pitched the advantages of its reliance on Amazon, Google and Microsoft cloud platforms in enabling a greater scale of market penetration, but also acknowledged the situation “creates complex dynamics that could give rise to conflicts of interest and adversely affect our access to compute”.

Anthropic signed a compute deal with Microsoft in November 2025.

Sales through Amazon and Google accounted for 11 percent of revenue in 2023, rising to 32 percent in 2024 and 47 percent in 2025, with the same third-parties responsible for collecting 60 percent of the $909m in outstanding customer bills at the end of 2025, up from 42 percent in 2024.

Anthropic’s customer base is also highly concentrated, with 12 percent of revenue last year coming from two unnamed customers.

The company books as revenue the full value of contracts offered through marketplaces, recording the platforms’ large portion of such deals as a marketing cost, an arrangement competitor OpenAI said inflates Anthropic’s revenues by billions of dollars. Anthropic said the arrangement follows established accounting practices.

Anthropic is seeking to hold an IPO in the coming weeks, with a valuation of about $2tn.