When Anthropic eventually makes its public market debut, a wide range of investors are positioned to walk away with extraordinary returns. Venture capital firms such as Menlo Ventures, Sequoia, Sound Ventures, and Spark Capital are each expected to see their holdings generate billions of dollars in value. Yet despite those headline-grabbing figures, the single entity standing to gain the most from Anthropic's IPO is not a traditional venture firm at all - it is Amazon.

A notable detail buried in Anthropic's S-1 filing reveals just how unusual the company's investor composition is. None of the prominent venture capital firms that backed the AI startup hold a stake large enough to appear in the principal stockholders' table, which requires at least a 5% ownership threshold. In most technology IPOs, lead venture investors typically hold double-digit percentage stakes in the companies they helped build from the ground up. Anthropic's case is different, and the explanation comes down to sheer scale. With the company carrying a private valuation approaching $965 billion, even a 1% stake represents close to $10 billion in value. Menlo Ventures, for instance, holds what has been reported as a roughly $14 billion position - yet that translates to only around 1.5% of the company's total equity.

Amazon's Unusual Investment Structure

Rather than traditional venture-style equity, Anthropic raised substantial capital from strategic partners - large technology companies that are simultaneously its investors and its business customers. Among those, Amazon occupies a position that dwarfs every other financial stakeholder in the company.

Amazon's relationship with Anthropic began in 2023, when the e-commerce and cloud giant committed to invest up to $4 billion in the AI startup. In the years since, that commitment has grown substantially. Crucially, Amazon structured a significant portion of its investment not as direct equity purchases but as convertible notes - a form of debt instrument that automatically converts into shares when a company undergoes an IPO or is acquired. This approach allowed Amazon to deploy large sums of capital while deferring the question of exactly how many shares it would receive until a liquidity event occurred.

According to Anthropic's S-1, Amazon held convertible notes with a principal balance of $6.2 billion as of June 30. That figure represents the entirety of Anthropic's outstanding debt. However, the true financial picture is far more striking. Because Anthropic's valuation climbed sharply across multiple successive funding rounds, the shares those notes are set to convert into became dramatically more valuable over time. Amazon's own financial disclosures placed the fair value of its note holdings at $97.9 billion as of the same date.

A Non-Cash Charge Reflecting Surging Value

The rapid appreciation of Amazon's convertible notes created an accounting obligation for Anthropic. As the value of what the company effectively owes Amazon grew, Anthropic was required to record those increases on its income statement. The relevant line item - described in the filing as "change in fair value of convertible notes, derivative liabilities, and SAFEs" - totaled $72.4 billion for the first half of 2026. It is important to note that this is a non-cash charge, meaning no actual funds left the company as a result of these accounting entries.

Under the terms outlined in the S-1, Amazon's convertible notes could ultimately convert into as many as 1.84 billion shares of Anthropic. A cap is in place, however, that limits Amazon's total ownership to 12% of Anthropic's partially diluted share count - a metric that includes certain shares not yet issued, such as those tied to employee stock options. Amazon retains the ability to waive this cap. Any portion of the notes that cannot convert in a given period due to this limitation will remain outstanding and convert in subsequent quarters, subject to the same ownership ceiling.

Equity Stakes on Top of Debt Holdings

The convertible notes represent only one layer of Amazon's exposure to Anthropic. According to Amazon's quarterly report for the period ending June 30, the company also invested $10 billion in nonvoting preferred stock during the second quarter of 2026. That investment was made in two equal tranches of $5 billion each, spread across Anthropic's two most recent funding rounds. When combined with the approximately $8 billion Amazon deployed into the convertible notes between 2023 and 2025, the company's total investment in Anthropic amounts to roughly $18 billion.

Beyond the financial returns that will flow from an eventual IPO, Amazon is also positioned to benefit commercially from its relationship with Anthropic for years to come. Anthropic has committed to spend a minimum of $110 billion on Amazon Web Services over the next decade, ensuring that Amazon's cloud division will continue to capture a significant portion of Anthropic's operating expenditure regardless of how the public markets value the AI company's stock.

Google Also Positioned for Significant Returns

Google is another major technology company set to benefit substantially from Anthropic's IPO. Court filings reported in the press indicated that Google held approximately 14% of Anthropic as of early last year, and the company has continued to invest since then, including a $10 billion contribution in April. Like Amazon, Google has likely seen its percentage stake diluted through subsequent large funding rounds. Independent analysts have estimated Google's current ownership at closer to 5.6%. In addition to its equity position, Google has secured cloud computing commitments from Anthropic totaling at least $114 billion through 2033, giving it a parallel commercial relationship of considerable scale.

Structural Tensions Acknowledged in the Filing

The venture capital firms that backed Anthropic in its earlier stages have little reason for dissatisfaction - their returns, while representing modest ownership percentages, translate into enormous absolute dollar gains given the company's valuation. Nevertheless, the picture that emerges from the S-1 is one in which the most consequential financial beneficiaries of Anthropic's public offering are the large technology companies that invested early and simultaneously became the company's most important infrastructure providers.

The filing itself does not shy away from acknowledging the tensions inherent in this arrangement. Anthropic's S-1 explicitly flags the risk that some of the same cloud providers supplying its computing infrastructure are also developing competing artificial intelligence models. The document notes that those providers may not always share Anthropic's strategic interests, raising questions about the long-term alignment between the AI company and the corporate giants on which it depends - and which stand to profit so significantly from its eventual market debut.