Anthropic‘s S-1 paints an unusual IPO picture: several venture firms expect billions from their positions, yet none of the named VCs — Menlo Ventures, Sequoia, Sound Ventures, Spark Capital — owns even 5% of the company, the threshold for appearing in the principal stockholders’ table. That is highly unusual for a tech IPO, where lead investors typically hold double-digit percentages. The explanation is Anthropic‘s scale: at a $965 billion private valuation, a 1% stake is worth nearly $10 billion, so Menlo’s roughly $14 billion position amounts to about 1.5% of the company.

Instead, the large stakes belong to strategic partners. Amazon is likely the single largest financial beneficiary of the IPO. It first backed Anthropic in 2023 with a commitment to invest up to $4 billion, and has since poured billions more. Much of that investment was structured as convertible notes rather than upfront stock. According to the S-1, Amazon holds convertible notes with $6.2 billion in principal outstanding as of June 30 — Anthropic‘s entire debt load. As Anthropic‘s valuation jumped across funding rounds, those notes became far more valuable; Amazon‘s own filings valued its note holdings at $97.9 billion as of June 30.

Because the notes’ value grew, Anthropic recorded the growing obligation on its books. A line item — “change in fair value of convertible notes, derivative liabilities, and SAFEs” — totaled $72.4 billion for the first half of 2026. The charge is non-cash. The S-1 says Amazon‘s notes could convert into as many as 1.84 billion shares, but a cap limits Amazon to 12% of Anthropic‘s “partially diluted” share count. Amazon can waive the cap, and notes that cannot convert stay outstanding and convert in later quarters under the same limit.

Notes are not Amazon‘s only holding. Amazon invested another $10 billion in nonvoting preferred stock in the second quarter, $5 billion in each of Anthropic‘s last two funding rounds, according to Amazon‘s quarterly report. Combined with the $8 billion it put into notes from 2023 through 2025, Amazon‘s total investment comes to about $18 billion. Beyond equity gains, Amazon will keep earning significant revenue from Anthropic, which committed to spend at least $110 billion on AWS over the next 10 years.

Google is also positioned for a major windfall. It held about 14% of Anthropic as of early last year, per court filings reported by The New York Times, and has invested more since, including $10 billion in April. Subsequent massive funding rounds likely diluted that stake; PitchBook analyst Harrison Rolfes estimates it is closer to 5.6%. Google has also secured at least $114 billion in cloud commitments from Anthropic through 2033.

The S-1 makes clear the biggest winners may be tech giants rather than traditional VCs. Amazon backed a would-be rival early and now sells it much of the computing power it runs on. The filing itself warns that some of those cloud providers also build rival AI models and may not always want the same things that Anthropic does.