Leaked Documents Reveal How Much OpenAI Pays Microsoft

Leaked documents are offering a closer look at OpenAI’s finances as the company faces growing attention around its revenue, expenses, and plans for an expected IPO. The documents, obtained by tech blogger Ed Zitron, outline how much OpenAI has paid Microsoft through their revenue-sharing agreement, as well as how much the company is spending on compute to run its models.

According to the leak, Microsoft received $493.8 million in revenue-share payments from OpenAI in 2024. In the first three quarters of 2025, that amount rose sharply to $865.8 million. OpenAI is widely reported to share about 20 percent of its revenue with Microsoft under a deal tied to Microsoft’s more than $13 billion investment, though neither company has confirmed this figure publicly.

The financial relationship runs both ways. A source told TechCrunch that Microsoft also sends about 20 percent of its earnings from Bing and Azure OpenAI Service back to OpenAI. Because Bing uses OpenAI technology and Azure OpenAI sells access to its models, part of Microsoft’s revenue is returned to the startup. The leaked figures reflect Microsoft’s net share, meaning they do not include the royalties paid to OpenAI from those services.

Microsoft does not break out revenue from Bing or Azure OpenAI, making it hard to determine exact payments. Still, the leaked numbers offer a rare look into OpenAI’s financial engine. Based on the commonly cited 20 percent revenue share, OpenAI’s revenue appears to be at least $2.5 billion in 2024 and $4.33 billion in the first three quarters of 2025, though other reports suggest it may be higher. CEO Sam Altman recently said OpenAI is generating well over $13 billion annually and could end the year with a revenue run rate above $20 billion. He also predicted the company could reach $100 billion by 2027.

The documents also indicate that OpenAI’s spending on inference — the compute needed to run AI models — is rising quickly. Zitron estimates the company spent around $3.8 billion on inference in 2024 and about $8.65 billion in the first nine months of 2025. While training costs are mostly covered by credits from Microsoft, inference expenses are largely paid in cash.

These numbers suggest OpenAI may be spending more on running its models than it earns, adding fuel to ongoing concerns about an AI bubble and raising questions about the long-term economics of the industry. Both OpenAI and Microsoft declined to comment.