Anthropic investors: S-1 caps Amazon at 12%, Google under 15%

Key takeaways

• Amazon and Google are Anthropic's largest strategic backers. Reuters counts at least $13 billion from Amazon and up to $40 billion committed by Google.
• The S-1 limits both tech giants: Amazon's remaining $6.2 billion of convertible notes stop converting at a 12% stake, and Google's holding is capped at just under 15%.
• Neither company controls the Claude maker. Google has no voting rights or board seat, and CNBC reports that Amazon's shares are nonvoting.
• Financial backers include Spark Capital, Lightspeed, ICONIQ, GIC, Coatue, Sequoia and Altimeter, plus individuals Jaan Tallinn and Eric Schmidt.
• Exact post-IPO ownership percentages for each investor have not been published. Price range and share count are still blank.

Anthropic investors are led by Amazon and Google, but the Claude maker's IPO filing caps both: Amazon's remaining $6.2 billion of convertible notes stop converting at a 12% stake, and Google's holding is capped at just under 15%. Neither controls the company.

What happened

Anthropic, the developer of the Claude AI models, made its Form S-1 registration statement public with the US Securities and Exchange Commission on Oct. 26, 2026, ahead of a planned Nasdaq listing under the ticker ANT. At about 13:34 UTC the same day, Reuters published a factbox listing the company's biggest investors, from Amazon and Alphabet's Google to Singapore's sovereign wealth fund GIC.

The filing also sets out, for the first time in an official document, how the two cloud giants' stakes are structured. Bullquill's earlier coverage covers the headline revenue and listing details and the compute costs and risk factors. This article focuses on the Anthropic investors and what each one holds.

Anthropic investors at a glance

Data as of Oct. 26, 2026, 18:00 UTC. Amounts are as reported; Bullquill has not independently totalled each investor's holdings.

What we know

Amazon's stake in Anthropic

Amazon began investing in 2023 through convertible notes. According to Reuters, it has put in at least $13 billion and agreed in April 2026 to invest up to $20 billion more, tied to commercial milestones. Under the S-1, $6.2 billion of those notes were still outstanding on June 30, 2026, and they convert at the IPO only until Amazon's total ownership would reach 12%, according to CNBC and Investing.com. CNBC also reported that Amazon's shares carry no vote and that it has no board or observer seat.

Google's stake in Anthropic

Google has committed up to $40 billion, including an initial $10 billion announced in April 2026, Reuters reported. Its ownership is capped at just under 15%, and it has no voting rights or board seat, according to reports on the filing by Investing.com and OfficeChai, consistent with Fortune's earlier reporting. CNBC said Anthropic agreed to let Google buy up to $10 billion of stock at the IPO price.

Partners, customers and rivals at once

The filing calls the cloud providers investors, customers, distribution partners and competitors simultaneously, Investing.com reported. Sales through the Google, Amazon and Microsoft cloud marketplaces made up 48% of Anthropic's revenue in the first half of 2026. Anthropic has committed to spend about $110 billion with Amazon through 2036 and at least $114.5 billion with Google through 2033. The S-1 warns that this overlap "may create complex situations that could lead to conflicts of interest," OfficeChai quoted.

What we don't know yet

• Final percentages. The S-1 does not yet show a price range or share count, so each investor's post-IPO percentage is unknown. Outside estimates vary widely and are not used here.
• Selling shareholders. It is not yet known whether any existing investor will sell shares in the offering.
• Lock-up terms. The length of any lock-up on early backers' shares has not been reported in detail.

Background

Anthropic's private valuation rose from $61.5 billion at the March 2025 Series E to $183 billion in September 2025, $380 billion in February 2026 and $965 billion after the $65 billion Series H in May 2026, according to Reuters. Before the filing went public, Bloomberg reported what some early backers' stakes were worth, led by Spark Capital's 2023 bet. The company's results also include a large accounting charge linked to those convertible notes, covered in our report on the first-half loss. More coverage is collected under Anthropic IPO.

What it means

The ownership caps and nonvoting structures matter for public buyers. They mean that Amazon and Google can profit heavily from Anthropic's growth without steering the company. Control stays with Anthropic's own governance. The same two companies also sell Anthropic its compute and resell its models. That makes their relationship central to how the market will judge the IPO, alongside the revenue and loss figures. The price range, due in a later amendment, will show what the stakes are actually worth.

This article is for information only and is not investment advice.