Anthropic's IPO prospectus submitted to investors has for the first time brought its intricate financial relationships with Amazon and Google into the open.

On September 29, according to this confidential document obtained by Reuters, nearly half of Anthropic's 2025 revenue was generated through the platforms of these two cloud giants, while both simultaneously serve as investors, computing power suppliers and direct competitors.

The prospectus shows that Anthropic's 2025 revenue was nearly $4.6 billion, up about 12 times year over year, but operating losses doubled over the same period to more than $8 billion. Behind this rapid growth is an increasingly deep structural dependence on a small number of partners - a risk Anthropic explicitly lists in the prospectus.

47% of revenue passes through the hands of two giants

The prospectus shows that in 2025, sales completed through the cloud platforms of Amazon.com (NASDAQ: AMZN) and Alphabet (NASDAQ: GOOG) totaled about $2.16 billion, accounting for 47% of total annual revenue.

That proportion has continued to climb - only 11% in 2023, rising to 32% in 2024, and approaching half last year.

Reuters calculated that Anthropic paid about $351 million in distribution fees to the two platforms, equivalent to about 16 cents going to Amazon or Google for every $1 of cloud platform revenue generated. This expense is recorded under the "sales, marketing and partner" operating expense item in Anthropic's financial statements.

Investor, supplier, distributor, competitor - four roles in one

The complexity of this financial relationship goes far beyond that.

Amazon and Google simultaneously play four roles: injecting tens of billions of dollars of investment into Anthropic, providing it with computing infrastructure, collecting payments from customers on its behalf, and also competing directly with it in AI.

By the end of 2025, Anthropic's irrevocable hosting and computing procurement commitments reached $54.6 billion. By early 2026, its total long-term commitments had exceeded $417 billion, covering 3.5 gigawatts of dedicated computing capacity.

In the prospectus, Anthropic characterizes the above relationships as a competitive advantage, saying that distributing the Claude model through the cloud platforms of Amazon, Google and Microsoft can use their huge sales networks to reach existing customers and achieve "a scale of market penetration that we believe would be difficult for any single institution to replicate directly."

But the prospectus also acknowledges that dependence on a small number of partners and suppliers "creates complex dynamics that may give rise to conflicts of interest and adversely affect our access to computing resources."

The document also points out that cloud service providers can see Anthropic's pricing and commercial terms, which may affect their decisions on computing allocation and the intensity of product promotion.

Two major customers each account for 12%, and there are no long-term contracts

Customer concentration is also a major risk.

The prospectus shows that two unnamed customers each contributed 12% of Anthropic's annual revenue.

Anthropic warns that most of its major customers are not bound by long-term contracts and may reduce or stop spending at any time.

At the accounts receivable level, as of the end of 2025, Anthropic had $909 million in uncollected customer accounts, 60% of which was collected on its behalf by Amazon and Google, up from 42% in 2024. Anthropic notes that if disputes or delays arise in this link, cash flow could still be affected even if the company has contracts directly with customers.

The dispute with OpenAI over revenue recognition

This prospectus also brings the dispute between Anthropic and OpenAI over revenue recognition back to the forefront.

Anthropic records the full amount of cloud platform marketplace contracts as revenue and treats platform commissions as marketing costs - on the basis that Anthropic is the "principal" in the transaction responsible for pricing and service delivery, in line with accounting standards.

But according to a Reuters report in June this year, OpenAI told investors and employees that this treatment inflated Anthropic's revenue by billions of dollars.

In response, Anthropic said the company follows established accounting standards and recognizes gross revenue because it is the "principal" in the transaction.