Leaked documents shed light into how much OpenAI pays Microsoft

After a year of crazy dealmaking and rumors of an upcoming IPOfinancial supervision of OpenAI is becoming increasingly intensive. Leaked documents obtained by tech blogger Ed Zitron provide further insight into OpenAI’s financial situation – specifically its revenues and computing costs over the past few years.

Zitron reported this week that Microsoft received $493.8 million in revenue share payments from OpenAI in 2024. In the first three quarters of 2025, that number rose to $865.8 million, according to documents he reviewed.

OpenAI reportedly will share 20% of its revenue with Microsoft as part of a previous deal that saw the software giant invest more than $13 billion in the powerful AI startup. (Neither the startup nor the people in Redmond have publicly confirmed this percentage.)

However, this is where things get a bit tricky, as Microsoft also shares revenue with OpenAI back about 20% of revenue from Bing and Azure OpenAI Service, a source familiar with the matter told TechCrunch. Bing is powered by OpenAI and the OpenAI Service sells cloud access to OpenAI’s models to developers and businesses.

The source also told TechCrunch that the leaked payments relate to Microsoft’s net revenue share, not gross revenue share. In other words, they don’t include what Microsoft paid to OpenAI from Bing and Azure OpenAI royalties. According to this person, Microsoft subtracts these numbers from internally reported revenue shares.

Microsoft doesn’t disclose in its financial statements how much it makes from Bing and Azure OpenAI, so it’s difficult to estimate how much the tech giant will recoup.

Still, the leaked documents offer insight into the hottest company in today’s private market — and not just how much it generates in revenue, but also how much it spends compared to those revenues.

So, based on the commonly reported 20% revenue share statistic, we can conclude that OpenAI’s revenue was at least $2.5 billion in 2024 and $4.33 billion in the first three quarters of 2025 – but very likely more. Previous messages from De Informatie posted OpenAI’s revenue in 2024 around $4 billion, and sales from the first half of 2025 $4.3 billion.

Altman also recently said that OpenAI’s revenues are “well more” than reported $13 billion per yearwill end the year above $20 billion in annualized sales (which is a projection, not an indication of actual sales), and that the company could even reach $100 billion by 2027.

According to Zitron’s analysis, OpenAI may have spent around $3.8 billion on inference by 2024. That spending increased to about $8.65 billion in the first nine months of 2025. Inference is the computing power used to run a trained AI model to generate responses.

OpenAI has historically relied almost exclusively on Microsoft Azure to provide compute access, although it has also signed deals with CoreWeave and Oracle, and more recently with AWS and Google Cloud.

Previous reports estimated OpenAI’s entire computing spend at approximately $5.6 billion by 2024 and the “cost of income”. $2.5 billion for the first half of 2025.

A source familiar with the matter told TechCrunch that while OpenAI’s training expenses are largely non-cash (that is, paid for with credits Microsoft granted to OpenAI as part of its investment), the company’s expenses are largely cash. (Training refers to the computational resources required to initially train a model.)

While not a complete picture, these numbers imply that OpenAI could spend more on inference costs than on revenue.

And these implications promise to add to the incessant AI chatter that has permeated every conversation from New York City to Silicon Valley. If modeling giant OpenAI really is still in the red running its models, what could this mean for the massive investments at staggering valuations for the rest of the AI ​​world?

OpenAI declined to comment. Microsoft did not respond to TechCrunch’s request for comment.

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