Following the leak of internal documents, OpenAI and Microsoft have once again become the center of public attention. Tech commentator Ed Zitron, citing sources with direct access to OpenAI’s financial disclosures, has unveiled details about the financial flows between the two companies under their revenue-sharing and cloud computing agreements. The documents shed light on the fiscal framework behind one of AI’s most influential partnerships, revealing that the maker of ChatGPT paid Microsoft $493.8 million in 2024—a figure that surged to $865.8 million in the first three quarters of 2025 alone.
The leaked materials confirm that these payments stem primarily from a revenue-sharing arrangement granting Microsoft approximately 20% of OpenAI’s earnings, a clause tied to Microsoft’s multi-billion-dollar investment in the company. Additionally, the documents indicate that Microsoft returns a portion of its own AI-related revenue to OpenAI—particularly income generated from AI features in Bing and the Azure OpenAI Service.
Meanwhile, inference-related expenses reportedly reached around $3.8 billion in 2024 and skyrocketed to approximately $86.5 billion in the first nine months of 2025. These figures underscore the immense costs associated with operating large language models (LLMs) at a global scale. Based on the disclosed revenue-sharing terms, OpenAI’s total revenue in 2024 is estimated to have been at least $25 billion, with a substantial increase projected for 2025—supported by the $865.8 million already paid to Microsoft through Q3.
The leaks further highlight the deep interdependence between the two firms. Microsoft’s Azure cloud infrastructure supports the majority of OpenAI’s model training and day-to-day operations, positioning Microsoft as far more than just an investor. Conversely, OpenAI’s models are now deeply integrated into Microsoft’s product ecosystem—from Bing to new enterprise tools. To date, neither company has issued a detailed public response confirming or denying the specific figures revealed in the leak.
The timing of this disclosure is particularly significant: just last month, OpenAI completed its transition to a for-profit structure. The company has reorganized as a Public Benefit Corporation (PBC), with Microsoft acquiring a 27% stake valued at roughly $135 billion—based on OpenAI’s overall $500 billion valuation. Under the new agreement, OpenAI has committed to utilizing approximately $250 billion worth of Microsoft Azure cloud services over the coming years. Early reports also suggest that the AI powerhouse, led by Sam Altman and having raised nearly $58 billion in total funding to date, aims to achieve $125 billion in annual recurring revenue by 2029.
