Nearly half of Anthropic's revenue arrives through Google, Amazon and Microsoft. Its filing lists that under risk factors.

Anthropic filed its S-1 on October 26 showing $16.286 billion of revenue for the first half of 2026, against $1.163 billion in the same period a year earlier. Nearly half of that revenue, 48%, came through cloud marketplaces run by Google, Amazon and Microsoft, up from 11% in 2023. Over the same six months, payments to its sales partners rose by about $2.7 billion.

The growth is the headline everywhere else, and it deserves to be. The more useful document is the invoice underneath it. This is the first audited account of how an AI company at this scale actually reaches its customers, and the answer is not outbound. It is shelf space, rented from three companies the filing itself files under concentration risk.

So the arrangement reads like this. You pay three companies to carry your product, commit $269.4 billion to buying computing power from the same three, and file the whole arrangement under concentration risk in your own prospectus. That is the go-to-market motion the industry spent 2026 trying to copy.

48% of revenue, and $2.7 billion more to the partners carrying it

The expense line is in the filing. “Sales, marketing, and partnerships” was $3,168 million for the six months ended June 30, 2026, against $120 million a year earlier. Filing coverage attributes about $2.7 billion of that increase to payments to sales partners. We could not retrieve the MD&A section explaining the line, so that split rests on reporting rather than on wording we read.

The rest of the picture is what B2B operators will misread. As of September 30, more than 11,900 customers were spending over $100,000 on a trailing basis, up from more than 950 a year earlier. Net revenue retention runs near 900%. Revenue per employee is above $6.6 million against roughly 5,300 staff.

Those are not numbers an outbound engine produces, and the people running outbound know it: sales leaders put AI-written email last of seven prospecting channels at 8%. The filing describes a product spreading inside accounts that were already buying, through a channel somebody else operates. The series ran 11% in 2023, 32% in 2024, 47% in 2025 and 48% in the first half of 2026, though the 2024 and 2025 figures exclude Microsoft, so the middle is not like for like.

The filing puts its own distributors in the risk factors

The sentence that matters is short. “A substantial portion of our revenue and accounts receivable is driven by a limited number of customers and distribution channels,” the risk factors summary says. The business section describes selling Claude across AWS, GCP and Azure through “a joint go-to-market approach with these CSPs,” and notes the company does this “while paying a fee to each CSP.” The fee percentages are not disclosed.

Reporting goes further, and should be read as reporting rather than quoted text: TipRanks says the filing warns that the three cloud partners can promote competing AI services and can see Anthropic's prices and customer agreements.

Strip the AI from that and it is the oldest commercial problem there is. A channel that moves volume for you also stands between you and the customer, learns your economics, and sells next to your competitors.

$269.4 billion of compute, owed to the same three companies

The dependency runs both ways, and two of the three are also among Anthropic's largest backers: Amazon's $53.4 billion of second-quarter non-operating income came mainly from its stake. Minimum compute commitments total about $269.4 billion: $114.5 billion to Google through 2033, $110 billion to Amazon through 2036, and $44.9 billion to Microsoft. Some of those payments are owed whether or not the capacity gets used.

One correction: the $80.748 billion first-half net loss is not an operating number. The operating loss was $693 million, Q2 produced $974 million of operating income, and $72.388 billion of the net figure is a fair-value change on convertible notes, derivatives and SAFEs, which the filing attributes to its own rising valuation.

The channels where nobody can see your prices

We have been writing variations of this for two months without the receipt. Private equity bought the trade show business and the organizer owns the meeting count. The venue operator running 20,000 events a year holds your attendee list. Meta published a conversion threshold B2B cannot clear and priced the shortfall at 28%. Each time, the channel worked and the company using it did not own the ledger.

The S-1 is the same story with audited numbers attached. Rented distribution is not cheap and not neutral. It charges in money, then charges again in information.

For the executive signing off a seven-figure GTM budget, the question is not which marketplace to join. It is which line buys a customer relationship that stays when the contract ends. The list does. The room does. A one-day event that produced a $2.4 million pipeline did, and nobody in that room could read the price list.

Every dollar moved this year from bought distribution into owned channels will look conservative in the planning meeting and correct by the second renewal, because the thing a rented channel never sells you is the relationship. Anthropic can afford both. Most companies reading its filing cannot, and will copy the half that shows up in the revenue chart rather than the half that shows up in the risk factors.

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