Amazon Is the Biggest Winner in Anthropic's IPO — Not the Venture Funds

When a startup the size of Anthropic takes its shares public, you would expect venture capital funds to top the list of winners. But a close reading of the IPO filing (Form S-1) paints a different picture: the largest stakes and the biggest gains are flowing to a corporate giant and commercial partner, Amazon, which invested early in a company widely regarded as a potential rival, and then went on to sell it the computing power that runs its models.

The paradox of small stakes in a giant company

The documents indicate that none of the major venture funds backing Anthropic — among them Menlo Ventures, Sequoia, Sound Ventures and Spark Capital — holds a stake of 5% or more, the threshold that would require the company to list the holder in its table of principal shareholders. This is unusual in tech IPOs, where the lead investor typically retains a double-digit percentage.

The reason is not any decline in investor confidence, but the sheer size of the company itself. At a private valuation of roughly $965 billion, just 1% is equivalent to about $10 billion. According to figures attributed to Bloomberg, Menlo Ventures' position — valued at around $14 billion — represents only about 1.5% of the company. In other words, the absolute returns are enormous, even as the percentages look modest.

How Amazon shrewdly built its position

Amazon's relationship with Anthropic began in 2023 with an investment commitment of up to $4 billion, a figure that has since multiplied several times over. But the decisive element was the structure: instead of taking shares outright, Amazon channeled a large portion of its money through convertible notes — debt that converts into equity upon a public offering or sale.

• The principal of these notes stood at $6.2 billion outstanding as of June 30, representing the entirety of Anthropic's debt.
• As the valuation climbed through successive funding rounds, the carrying value of those notes on Amazon's books rose to $97.9 billion as of the same date.
• The notes could convert into as many as 1.84 billion shares, but a contractual cap limits Amazon's share to 12% of the "partially diluted" share count — a ceiling the company can waive.
• Whatever cannot be converted remains outstanding, to be converted in later quarters subject to the same restriction.

Alongside the notes, Amazon invested $10 billion in non-voting preferred shares during the second quarter, with $5 billion in each of the two most recent funding rounds. Adding the roughly $8 billion injected into the notes between 2023 and 2025, Amazon's total commitment comes to nearly $18 billion.

A multibillion-dollar accounting line that never leaves the treasury

The sharp rise in the value of the convertible notes shows up on Anthropic's books as a ballooning liability. The company recorded an income-statement line item titled "change in fair value of convertible notes, derivative liabilities and SAFE agreements" worth $72.4 billion in the first half of 2026. It is important to understand the nature of this figure: it is a non-cash charge, meaning no money actually leaves the company — it is an accounting revaluation of what it owes its partners.

Double gains: an ownership stake and a cloud bill

Amazon's gains do not stop at rising share value. Anthropic has committed to spending at least $110 billion on AWS services over the next ten years. That means a large share of the money the company raises will flow back to one of its biggest investors in the form of operating revenue.

The situation is similar for Google, which owned about 14% of Anthropic at the start of last year according to court filings, before that relative weight was diluted by subsequent massive funding rounds; PitchBook analyst Harrison Rolfes estimates the current stake at roughly 8%, following an additional $10 billion investment in April. Google also secured cloud commitments from Anthropic worth up to $114 billion through 2033.

A warning inside the IPO filing itself

Anthropic has not ignored the sensitivity of these relationships. Its filing flags an explicit risk factor: some of the cloud providers it relies on are simultaneously developing competing AI models, and their interests may not always align with the company's.

The takeaway is that the generative AI funding model has reshuffled the balance of power. Big Tech companies are no longer merely a potential eventual acquirer; they are now financier, supplier and competitor all at once — combining three channels of return: appreciation in the value of their stake, long-term compute contracts, and a strategic position in the large-model market. Venture funds, for their part, will book real billions — just not the seat of the biggest winner.

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