After a year of frenzied trading and rumors of an upcoming IPO, financial scrutiny of OpenAI has intensified. Leaked documents obtained by technology blogger Ed Zitron shed more light on OpenAI’s financials, specifically its revenue and computing costs over the past few years.
Zitron reported this week that Microsoft will receive $493.8 million in revenue sharing from OpenAI in 2024. In the first three quarters of 2025, that number jumped to $865.8 million, according to documents he reviewed.
OpenAI is reportedly sharing 20% of its revenue with Microsoft as part of a previous deal in which the software giant invested more than $13 billion in the powerhouse AI startup. (Neither the startup nor the people in Redmond publicly acknowledge this percentage.)
But this is where things get a little tricky. That’s because Microsoft also shares revenue with OpenAI, kicking back about 20% of revenue from Bing and Azure OpenAI Service, people 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 enterprises.
The source also told TechCrunch that the leaked payments refer to Microsoft’s net revenue share, not its gross revenue share. In other words, it does not include what Microsoft paid to OpenAI from Bing and Azure OpenAI royalties. Microsoft subtracts these numbers from its internally reported revenue share numbers, the person said.
Microsoft doesn’t disclose revenue from Bing and Azure OpenAI in its financial statements, so it’s difficult to estimate how much kickbacks the tech giant is giving out.
Nevertheless, the leaked documents provide a window into the hottest companies in the private markets today, allowing us to see not only how much revenue they make, but also how much they spend relative to that revenue.
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So, based on the widely reported 20% revenue share statistic, we can assume 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 is very likely that it will exceed that. A previous report in The Information estimated OpenAI’s 2024 revenue at approximately $4 billion and the first half of 2025 revenue at $4.3 billion.
Altman also recently said that OpenAI’s revenue is “well above” the reported $13 billion per year, that the annual revenue run rate (this is a projection, not actual revenue guidance) will exceed $20 billion by the end of the year, and that the company could even reach $100 billion by 2027.
According to Zitron’s analysis, OpenAI could have spent approximately $3.8 billion on inference in 2024. That spending rose to about $8.65 billion in the first nine months of 2025. Inference is the computing used to run trained AI models and generate responses.
OpenAI has so far relied almost exclusively on Microsoft Azure to provide compute access, but it also has deals with CoreWeave, Oracle, and more recently AWS and Google Cloud.
Previous reports estimated OpenAI’s overall compute spending in 2024 to be approximately $5.6 billion, with a “cost of revenue” of $2.5 billion in the first half of 2025.
People familiar with the matter told TechCrunch that while most of OpenAI’s training costs are paid for in non-cash terms, i.e. in credits that Microsoft gave OpenAI as part of its investment, the company’s inference costs are mostly in cash. (Training refers to the computing resources required to initially train the model.)
Although not the complete picture, these numbers suggest that OpenAI may be spending more on inference costs than revenue.
And these effects promise to add to the constant AI bubble chatter that permeates every conversation from New York City to Silicon Valley. If modeling giant OpenAI is indeed still losing money on model runs, what does this mean for the rest of the AI world’s massive investments at staggering valuations?
OpenAI declined to comment. Microsoft did not respond to TechCrunch’s request for comment.
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