PBC is relying more and more on Alphabet Inc.’s Google, Amazon.com Inc. and Microsoft Corp. to sell its artificial intelligence technology to customers, despite the three companies being rivals, investors and key suppliers of computing power.

Sales through the hyperscalers’ cloud marketplaces accounted for 48% of Anthropic’s revenue in the first half of 2026, up from 11% in 2023, according to the company’s Initial Public Offering filing published Monday. The cloud providers bill customers and pass the payments to Anthropic minus their fees. Levies Anthropic paid to channel partners, a category that includes the cloud providers, rose $2.7 billion in the first half from a year earlier.

The setup has fueled Anthropic’s fast growth. Sales hit $11.6 billion in the second quarter, when Anthropic posted a $974 million operating profit.

Anthropic’s IPO will be a key test of AI sentiment among public market investors, who already appear more sensitive to the high costs of AI buildouts. Reports of Anthropic’s third-quarter revenue growth slowing compounded a broader tech selloff earlier this month amid concerns that AI spending may be outpacing demand.

At the same time, the S-1 filing warns of risks. Anthropic describes the cloud providers as “investors, customers, distribution partners and competitors” all at once. It cautions that the companies have “visibility into our pricing and commercial terms.”The filing also says the cloud companies could favor their own AI models, and that Anthropic’s ties to them have attracted antitrust scrutiny and could draw more.

Anthropic has previously been criticized for “circular deals” in the tech ecosystem, with the same companies both putting cash into its balance sheet and taking it out. Anthropic is a significant Amazon Web Services customer, using Amazon data centers and chips to train and run its Claude models, while Amazon offers Claude through its Bedrock platform. Similarly, Anthropic uses Google’s custom AI chips, and Google sells Claude through its own cloud platform.

Anthropic depends on the same companies for computing power. It has committed to spend at least $114.5 billion with Google through 2033, $110 billion with Amazon through 2036 and $44.9 billion with Microsoft, whether or not it uses the capacity.

The figures add to the frenemy dynamics. When Anthropic struck its Amazon deal in April, it called AWS its “primary training and cloud provider for mission-critical workloads.”But its minimum commitment to Google is larger and runs over a shorter period. Anthropic also estimates it will pay another $125 billion to $150 billion for additional Tensor Processing Unit computing capacity from Google and other providers, to be delivered from 2028 to 2031.

Amazon and Google are major Anthropic shareholders, but the filing doesn’t disclose the size of their stakes. Their shares are non-voting, so they aren’t included in a table listing owners of more than 5% of Anthropic’s voting securities. Anthropic said elsewhere in the filing that Amazon and Google will each own more than 5% of the company after preferred shares and certain convertible notes are converted in connection with the offering.

Amazon has forged a deep investment and commercial relationship with Anthropic since agreeing in 2023 to invest as much as $4 billion. It’s since invested about $18 billion in Anthropic and committed up to an additional $15 billion, subject to certain conditions, according to the filing.

Amazon also holds convertible notes from purchase agreements in 2023 and 2024 that could convert into as many as 1.84 billion Anthropic shares, equivalent to about 10.9% of the company’s fully diluted shares as of June. That doesn’t include Amazon’s existing equity holdings, and is subject to a provision that prevents the notes from converting if doing so would push Amazon’s total ownership above 12%, unless Amazon waives that limit. Any portion of the notes that exceed the cap will be automatically rolled into a new note that can convert at the end of subsequent quarters, subject to the same cap.

Google has invested about $23 billion in Anthropic over multiple deals and committed to invest an additional $20 billion tied to performance targets. Its stake is capped at 14.99% under its latest financing deal, though Google can also waive that limit.

The filing spells out how Anthropic has entwined its own success with the cloud companies. Moving its workloads to other providers would be “costly, time-consuming” and could hurt its compute efficiency, the company says.

Anthropic’s dependence doesn’t end with the three cloud giants, however. It also leans on other suppliers. It has $161.2 billion in equipment leases with Broadcom Inc. and has agreed to spend up to $120.5 billion on computing power from SpaceXAI. The firm also says chipmaker Taiwan Semiconductor Manufacturing Co. has at times been unable to meet demand.