The cloud infrastructure race has always been about scale. Now, however, it is increasingly about margin. A new report from Semianalysis shows that Amazon.com Inc. (NASDAQ:AMZN) has pulled measurably ahead of its cloud rivals, and the engine driving that gap is not simply raw compute capacity. It is the structural economics of how Claude operates on Amazon Bedrock.

AWS Margin Growth Is Not an Accident

In Q1 2026, AWS posted revenue of $37.6 billion, up 28% year-over-year. That growth rate marked the fastest expansion in 15 quarters. More importantly, AWS operating margin reached 37.7%, rising for three consecutive quarters. Meanwhile, Semianalysis research shows AWS EBIT margins expanded by 213 basis points quarter-over-quarter. Competitors, by contrast, are not keeping pace. Microsoft Corporation's (NASDAQ:MSFT) Intelligent Cloud gross margin percentage declined slightly in Q1, due to the cost of scaling AI infrastructure, per Microsoft's own investor disclosures. That is a meaningful contrast: AWS is expanding margins as AI spending rises, while Azure is compressing them.

The Bedrock Deal Structure Is the Key

Most coverage of Claude's success focuses on user growth and revenue milestones. However, the more consequential story for investors lies in how the AWS-Anthropic commercial structure actually works. According to Semianalysis, Anthropic acts as the seller of record when Claude tokens move through Amazon Bedrock. AWS, therefore, earns both an infrastructure fee and a distribution revenue share for every token sold.

This arrangement functions like a high-margin royalty stream layered on top of AWS's existing compute revenue. In other words, AWS gets paid twice, ...