MW Is OpenAI outgrowing Microsoft? A new Amazon alliance raises the stakes.

By Christine Ji

A reported leaked memo from OpenAI's revenue chief signals a deepening rift with Microsoft, as the ChatGPT creator deepens its relationship with Amazon

Amazon invested $50 billion in OpenAI in February and provided the company with 2 gigawatts of Trainium capacity.

OpenAI and Microsoft's longstanding relationship might be coming under pressure as OpenAI turns to Amazon.com to fuel its growth, according to a CNBC report Monday.

In a Sunday memo, OpenAI Chief Revenue Officer Denise Dresser called OpenAI's partnership with Amazon (AMZN) as the key to unlocking artificial-intelligence monetization in the enterprise market - adding that Microsoft $(MSFT)$ has limited its ability to meet enterprises where they are, according to the CNBC report. Many of OpenAI's enterprise clients are accessing its models through a platform on Amazon Web Services called Bedrock, and Dresser called the demand "staggering."

The enterprise market has emerged as a key battleground for dominance among leading AI companies, as Anthropic wowed the market with its meteoric revenue growth in the first few months of 2026. Dresser wrote that Anthropic has made a "strategic misstep to not acquire enough compute," adding that "the market is ours to win, let's execute accordingly."

Dresser also criticized Anthropic's strategy for being built on "fear, restriction, and the idea that a small group of elites should control AI."

OpenAI and Anthropic did not immediately respond to MarketWatch requests for comment.

Read: Anthropic appears to have overtaken OpenAI on this key financial metric

Last October, OpenAI officially transitioned into a public benefit corporation, which has decreased Microsoft's influence on the AI company and allowed OpenAI to secure more access to compute through other cloud providers. While Microsoft has been an investor in OpenAI since 2019 - investing $13 billion in the company over the years - the relationship between the two parties has evolved into "frenemy" territory as Microsoft dedicates compute to its internal projects such as Copilot.

As Microsoft's control over OpenAI lessens, OpenAI has been strengthening its relationship with Amazon. Last November, OpenAI signed a $38 billion deal with Amazon to use Nvidia (NVDA) chips for ChatGPT training and inference workloads.

In February, Amazon announced plans to invest up to $50 billion in OpenAI and provide OpenAI with 2 gigawatts of Trainium capacity, referring to the AI chips developed by AWS. As part of the deal, AWS and OpenAI are collaborating to create exclusive agentic-AI environments and features for Bedrock customers.

Amazon's stock has gained 3.5% so far this year, while Microsoft shares have dropped 21.2%. By comparison, the S&P 500 SPX is little changed in 2026 to date.

Representatives from Amazon and Microsoft did not immediately respond to MarketWatch requests for comment.

See more: Amazon's CEO doubles down on AI spending: 'We are not going to be conservative'

Anthropic has also been actively signing more compute deals to service growing demand for its products. Last week, the company expanded its existing agreement with Broadcom $(AVGO)$ and Google $(GOOGL)$ $(GOOG)$ for 3.5 gigawatts of compute capacity. Anthropic also inked a deal with the neocloud company CoreWeave (CRWV) last Friday.

-Christine Ji

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April 13, 2026 13:20 ET (17:20 GMT)

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