New documents showing OpenAI’s money flow with Microsoft have surfaced, giving outsiders a rare look at the finances of one of the tech world’s most watched companies as it deals with growing questions about its business operations.

Tech writer Ed Zitron got his hands on internal papers that show how much money changed hands between the artificial intelligence company and its biggest backer as reported by Tech Crunch. The records reveal Microsoft pulled in $493.8 million from OpenAI in 2024 through their revenue-sharing agreement. That figure climbed to $865.8 million during the first nine months of 2025, Zitron wrote this week.

Two-way money flow between tech giants

The arrangement between the two companies works both ways. OpenAI hands over 20% of what it makes to Microsoft, part of the terms when the software company put more than $13 billion into the startup. Neither side has said publicly whether that percentage is accurate.

But the money doesn’t just flow in one direction. A person with direct knowledge of the deal told that Microsoft also gives OpenAI about 20% of what comes in from Bing and Azure OpenAI Service. Bing’s search engine runs on OpenAI technology, while Azure OpenAI Service lets other companies and programmers pay to use OpenAI’s tools through the cloud.

The numbers don’t tell the whole story

The payments Zitron saw represent what Microsoft keeps after subtracting what it owes OpenAI from Bing and Azure. That means the leaked numbers show the net amount, not the total before those deductions. Microsoft doesn’t list Bing or Azure OpenAI earnings separately in its public financial reports, making it hard to figure out the full picture.

Still, the leaked information offers a window into a company that private investors are watching closely. The papers show not just how much money OpenAI brings in, but also how much it spends to keep running.

Using the 20% revenue-sharing number, simple math suggests OpenAI made at least $2.5 billion in 2024. For the first three quarters of 2025, that figure was at least $4.33 billion, though the real numbers are probably higher.

OpenAI chief Sam Altman recently said the company’s revenue is “well more” than $13 billion yearly. He added that by year’s end, the annualized revenue run rate will top $20 billion and could reach $100 billion by 2027.

Computing costs climb fast

The spending side tells a different story. That number jumped to roughly $8.65 billion for the first nine months of 2025. Inference means the computer power needed to run trained AI systems when they respond to users.

Microsoft Azure has been OpenAI’s main source for computing resources, though the company has also signed deals with CoreWeave, Oracle, and more recently with AWS and Google Cloud.

A source close to the situation explained  that OpenAI pays for training mostly through credits Microsoft gave as part of its investment, not actual cash. Training means the computing work to build a model from scratch. But inference costs come mostly out of pocket as real money.

When you put these numbers together, they suggest OpenAI might be spending more on inference alone than it makes from selling its services.

That possibility is feeding ongoing debates about whether the artificial intelligence industry is overvalued. If OpenAI, the biggest name in AI models, is still losing money running its technology, people are asking what that means for all the other companies getting massive investments at sky-high valuations.

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