OpenAI and Microsoft have come under new discussion after leaked internal documents, released by technology blogger Ed Zitron (who obtained them from sources with direct access to OpenAIâs financial disclosures), revealed how much money has moved between the two companies under their revenue-share and cloud-compute agreements. The files provide an unusually detailed look at the financial structure behind one of the most influential partnerships in the AI domain, showing that the ChatGPT maker paid Microsoft $493.8 million in 2024, followed by a sharp rise to $865.8 million in the first three quarters of 2025.
The leaked material confirms that these payments originate primarily from a revenue-sharing agreement that entitles Microsoft to roughly 20% of OpenAIâs revenue, a term tied to Microsoftâs multi-billion-dollar investment in the company. The documents also show that Microsoft passes a portion of its own AI-related revenue back to OpenAI, particularly income from Bingâs AI-powered features and the Azure OpenAI Service.
Meanwhile, according to the leaks, inference spending reached about $3.8 billion in 2024 and surged to around $8.65 billion in just the first nine months of 2025. These figures underscore how expensive it is to operate large language models (LLMs) at a global scale. Using the revenue-share percentage described in the documents, estimates suggest that OpenAIâs revenue was at least around $2.5 billion in 2024, rising much higher in 2025 based on the $865.8 million paid to Microsoft by the third quarter.
The leak also shows how closely the two companies rely on each other. Microsoftâs Azure cloud powers most of OpenAIâs training and day-to-day model operations, making Microsoft more than just an investor. At the same time, OpenAIâs models now play a major role in Microsoftâs products, from Bing to new enterprise tools. In the meantime, neither company has issued a detailed public reply to the specific numbers disclosed in the leak.
The timing of this revelation is even more significant because last month, OpenAI completed its transition to a for-profit structure. The company has reorganized as a public benefit corporation (PBC), and Microsoft has taken a 27% ownership stake valued at an estimated $135 billion based on OpenAIâs $500 billion valuation. Under the new terms, OpenAI has committed to using around $250 billion worth of Microsoftâs Azure cloud services over the coming years. Some earlier reports also suggest that the Sam Altman-led AI giant (which has so far raised around $58 billion in total funding) is aiming for $125 billion in annual recurring revenue by 2029.
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