After a year marked by a flurry of deals and anticipation of an IPO, OpenAI is facing increased financial scrutiny. Tech blogger Ed Zitron’s acquisition of leaked documents offers further insight into OpenAI’s financial situation, particularly its income and computing expenses, over the last couple of years.
Zitron reported this week that OpenAI paid Microsoft $493.8 million in revenue share during 2024. According to the documents he reviewed, this figure rose to $865.8 million in the first three quarters of 2025.
Reportedly, OpenAI gives Microsoft 20% of its income as part of a prior agreement in which the software giant invested more than $13 billion in the influential AI startup. (Neither the startup nor the Redmond-based company has officially verified this percentage.)
However, the situation becomes complicated because Microsoft also shares income with OpenAI, returning about 20% of revenues from Bing and Azure OpenAI Service, according to a TechCrunch source. OpenAI powers Bing, and the OpenAI Service provides cloud access to OpenAI’s models for developers and businesses.
According to the source, the leaked payments relate to Microsoft’s net revenue share, not the gross revenue share. In other words, they don’t reflect Microsoft’s payments to OpenAI from Bing and Azure OpenAI royalties. According to this person, Microsoft subtracts these amounts from its internally reported revenue share figures.
Microsoft’s financial statements do not detail its earnings from Bing and Azure OpenAI, making it difficult to estimate the tech giant’s kickback.
Nonetheless, the leaked documents offer a glimpse into today’s hottest private market company, revealing not only its income but also its spending in relation to that income.
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Therefore, using the widely cited 20% revenue-share statistic, we can deduce that OpenAI’s revenue was at least $2.5 billion in 2024 and $4.33 billion in the first three quarters of 2025, but it was most likely higher. According to earlier reports from The Information, OpenAI’s revenue was approximately $4 billion in 2024 and $4.3 billion in the first half of 2025.
Altman stated recently that OpenAI’s revenue is “well more” than the reported $13 billion annually, will exceed $20 billion in annualized revenue run rate by the end of the year (a projection, not real revenue guidance), and may even reach $100 billion by 2027.
According to Zitron’s analysis, OpenAI may have spent around $3.8 billion on inference in 2024. In the first nine months of 2025, that cost rose to about $8.65 billion. Inference refers to the processing power required to generate responses from a trained AI model.
OpenAI has historically relied almost exclusively on Microsoft Azure for compute access, but it has also made agreements with CoreWeave and Oracle, and more recently with AWS and Google Cloud.
According to previous reports, OpenAI’s total compute expenditure for 2024 was roughly $5.6 billion, and its “cost of revenue” for the first half of 2025 was $2.5 billion.
According to a source familiar with the situation, OpenAI’s training expenditure is largely non-cash, meaning it is paid for with credits Microsoft granted OpenAI as part of its investment, whereas the firm’s inference spending is primarily cash. (Training is the compute resources needed to initially train a model.)
These figures, while incomplete, indicate that OpenAI may be spending more on inference costs than it makes in revenue.
Those implications are expected to fuel the ongoing AI bubble discussion that has permeated every conversation from New York City to Silicon Valley. What might it mean for the massive investments at astounding valuations in the rest of the AI world if model giant OpenAI is still losing money running its models?
OpenAI made no comments. Microsoft did not answer TechCrunch’s request for comment.
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