OpenAI Accuses Anthropic of Inflating Revenue by $8 Billion in Internal Memo

The Accounting Clash

A four-page internal memo from OpenAI Chief Revenue Officer Denise Dresser, sent to staff on Sunday and obtained by CNBC and The Verge, has ignited a public accounting dispute between the two leading AI companies. Dresser accused Anthropic of inflating its widely cited $30 billion annualised revenue run rate by approximately $8 billion through its choice of revenue recognition method.

The disagreement centres on how each company books sales through cloud distribution partners. Anthropic records the full amount billed through AWS, Azure, and Google Cloud as top-line revenue on a gross basis, including the cloud providers' cut. OpenAI reports its Microsoft Azure revenue on a net basis, deducting the partner's share. Both approaches are permissible under US GAAP, but OpenAI's internal analysis places Anthropic's comparable figure closer to $22 billion.

The IPO Stakes

The timing is no accident. Both companies are preparing for potential initial public offerings, with Anthropic reportedly targeting October 2026 at a $380 billion valuation, while OpenAI is eyeing a window as early as Q4. On Polymarket, bettors currently give Anthropic a 66% chance of completing its IPO first. When Anthropic files its prospectus, auditors will scrutinise the $30 billion headline figure closely.

The Amazon Pivot

Perhaps the most striking element was Dresser's candid assessment of OpenAI's Microsoft partnership. While calling it 'foundational,' she acknowledged it has 'limited our ability to meet enterprises where they are,' with many preferring Amazon's Bedrock platform. Since the $50 billion Amazon deal was announced in late February, inbound enterprise demand has been described as 'staggering.' OpenAI's enterprise business currently accounts for 40% of revenue and is on track to reach parity with its consumer business by year-end.

The Competitive Landscape

Ramp data tracking corporate payments shows Anthropic at 30.6% of enterprise AI-paying customers versus OpenAI's 35.2%, with a projected crossover within two months. Dresser also took aim at Anthropic's compute strategy, claiming the company made a 'strategic misstep' by not acquiring enough capacity, pointing to throttling and unreliable uptime as consequences.