Leaked files expose OpenAI’s huge payments to Microsoft

OpenAI has come under fresh attention after leaked documents revealed new details about its income, spending and its financial relationship with Microsoft. The documents, obtained by tech blogger Ed Zitron, outline OpenAI’s revenue figures and the cost of running its models over the past two years.

Zitron said that Microsoft received $493.8 million from OpenAI in 2024 through revenue sharing. In the first three quarters of 2025, this amount rose to $865.8 million. According to unnamed sources quoted by TechCrunch, OpenAI gives Microsoft 20%t of its revenue under their large investment agreement.

The same sources said Microsoft also returns about 20% of revenue from Bing and Azure OpenAI Service to OpenAI. These payments are adjusted internally before Microsoft reports its final revenue share totals, which makes the full movement of money between the two companies difficult to follow.


CEO Sam Altman recently said that OpenAI’s yearly revenue is far higher than the figure of $13 billion often reported. He added that the company could reach an annualised revenue run rate of more than $20 billion by the end of 2025.

The leaked documents also suggest that OpenAI spent about 3.8 billion dollars on inference in 2024. Inference refers to the computing power required to run an already trained model and produce responses for users.

This rose to around $8.65 billion in the first nine months of 2025. Most of this compute comes from Microsoft Azure, although the company also has agreements with CoreWeave, Oracle, AWS and Google Cloud.

A source told TechCrunch that Microsoft often covers training costs through credits, but inference costs are mostly paid in cash. This creates a heavy financial load for OpenAI. The figures suggest that the company may be spending more on inference than it is earning in revenue.