Anthropic's S-1: What Amazon, Google and Broadcom Hold and Can Sell

Why it matters

The cheapest holders of Anthropic are the ones with the clearest paths to sell. A secondary holder who bought at $589 pre-split, $58.90 now, sits above a strategic partner that paid a seventeenth of that and whose notes keep converting every quarter at the lowest of the fixed price, the IPO price and the 10-day trailing average. The lockup schedule in our October 26 note covers employees and investors. This is the other half of the supply calendar.

Amazon: $6.2 billion in, up to 1.84 billion shares out

Anthropic has issued $10.2 billion of convertible notes since November 2023 to two investors. What remains outstanding is Amazon's, all of it non-interest-bearing rollover paper that could not convert earlier without breaching the cap.

At the IPO the notes convert at the lower of those fixed prices and the IPO price, up to the point where Amazon would hold 12% of the company on a fully diluted basis. Whatever cannot convert is reissued as a rollover note and converts at the end of each following quarter at the lowest of the fixed price, the IPO price and the 10-day trailing average, again up to the cap. Amazon can waive the cap at its discretion. Anything still outstanding at maturity is repaid in cash or netted against what Amazon owes Anthropic under their commercial agreements.

At the Series H price, 1.84 billion shares are worth about $108 billion against $6.2 billion of notes. That gap is the $72.4 billion fair-value charge that produced the first-half GAAP loss.

The $77 billion that has not been drawn

None of it is expected to be drawn before the listing. The Google draws are triggered by compute agreements and trailing-revenue targets the company says it has already surpassed. The Amazon tranches unlock as Trainium capacity milestones are met. The Broadcom facility is different in kind: it exists solely to pay quarterly rent on TPU equipment under a 2026 lease, carries 9% interest paid in kind, rises to 13% with conversion at 85% of market if revenue conditions are missed, and on a change of control Broadcom can take 150% of principal in cash. Notes under it mature 57 to 63 months after the draw period starts and are secured, on a junior basis, by the leased equipment. The three facilities together could put another 1.3 billion shares into Class N at the Series H price, before any discount.

How the partners get out

Class N carries no vote. Economically it is Class A, and it becomes Class A on transfer to anyone unaffiliated. Google's registration agreement runs to February 2033: a single demand registration in the first year after listing for any shares not already saleable under Rule 144, then a shelf registration within 60 days of each quarterly closing. Broadcom has its own registration agreement for converted shares. The lockup tiers for holders above 0.5% of the company run up to 365 days, and the partners are in that tier. After that, the partners' stock sells like anyone else's.

What the S-1 leaves blank: the number of Class N shares Amazon actually receives at the IPO, and the rollover balance that stays outstanding. Both depend on the offering size and the price, and arrive with the amendment.

Sources

• Anthropic, PBC Form S-1, filed October 26, 2026 (SEC accession 0001628280-26-067168): Liquidity and Capital Resources, Convertible Notes; Description of Capital Stock, Registration Rights; Risk Factors.
• PMView: Anthropic, funding rounds, secondary market price.