Anthropic's IPO is being framed as a venture-capital payday. The S-1 says something different: no VC firm holds 5% of the company. The largest financial winner sits in Seattle — and it also sells the company its data centers.

According to the prospectus published Monday, none of the firms that backed Anthropic — Menlo Ventures, Sequoia, Sound Ventures, Spark Capital — clears the 5% threshold required to appear in the principal stockholders' table. That is unusual for a tech IPO, where lead venture investors normally hold double-digit stakes. The reason is sheer size: at a $965 billion private valuation, a 1% stake is worth nearly $10 billion. Menlo's roughly $14 billion position is therefore about 1.5% of the company, according to Bloomberg figures reported by TechCrunch.

$6.2 billion of debt, valued at $97.9 billion

Amazon structured much of its investment as convertible notes instead of taking stock upfront — debt that converts into shares at an IPO or sale. Per the S-1, Amazon holds notes with $6.2 billion in principal outstanding as of June 30. That is Anthropic's entire debt load.

But as the company's valuation climbed across successive funding rounds, the shares those notes convert into became far more valuable. Amazon's own filings valued the note holdings at $97.9 billion as of June 30. They could convert into as many as 1.84 billion shares — roughly 10.9% of fully diluted shares — subject to a contractual cap of 12% of Anthropic's "partially diluted" share count, which Amazon can waive. Notes that cannot convert stay outstanding and convert in later quarters.

The climb was steep enough that Anthropic had to mark the growing obligation on its own books. The line item "change in fair value of convertible notes, derivative liabilities, and SAFEs" totalled $72.4 billion for the first half of 2026. The charge is non-cash: no money left the company.

Then there is equity. In the second quarter Amazon put $10 billion into nonvoting preferred stock — $5 billion into each of Anthropic's last two funding rounds. Combined with the $8 billion it put into the notes from 2023 through 2025, Amazon's total outlay is about $18 billion, with up to $15 billion more committed subject to conditions.

The supplier is also the customer

The bigger return may not come from the balance sheet but from the income statement. Anthropic has committed to spend at least $110 billion with AWS through 2036. Google has invested about $23 billion, with $20 billion more tied to performance targets and its stake capped at 14.99% — and Anthropic has promised it at least $114.5 billion of cloud spending through 2033. Microsoft holds a $44.9 billion compute commitment.

That dependency is already visible in the numbers. Some 48% of Anthropic's first-half 2026 revenue came through cloud marketplaces operated by Google, Amazon and Microsoft, up from 11% in 2023. The company paid $2.7 billion more to channel partners, including those clouds, than a year earlier; the clouds bill customers and pass payments on after deducting fees. In the second quarter Anthropic reported $11.6 billion in sales and $974 million in operating profit.

The filing describes those partners in a single phrase as "investors, customers, distribution partners and competitors," and warns they have "visibility into our pricing and commercial terms" and may prefer their own models.

Venture firms will do well out of the listing, just with smaller percentage stakes than is customary. The structural finding in the prospectus is different: the largest economic beneficiary is a company that funded an early rival, now sells it a large share of its computing, and takes a cut of every dollar the rival sells through its marketplace.

Sources