What happened
Leaked documents detail OpenAI's financial relationship with Microsoft, revealing OpenAI paid $865.8 million in revenue sharing to Microsoft in Q1-Q3 2025, an increase from $493.8 million in 2024, while Microsoft returns approximately 20% of revenues from Bing and Azure OpenAI Service. OpenAI's inference spending on Microsoft Azure reached $8.67 billion in Q1-Q3 2025, more than doubling 2024's $3.7 billion. Microsoft's revenue share is projected to decrease from 20% to 8% by 2030. Microsoft holds a ~$135 billion investment in OpenAI Group PBC, representing ~27% diluted shares, with both Microsoft and OpenAI's non-profit each holding about one-third of shares.
Why it matters
The revealed financial structure highlights a significant operational constraint for OpenAI, demonstrating substantial dependency on Microsoft Azure for core AI inference workloads. The escalating inference costs, reaching $8.67 billion in Q1-Q3 2025, introduce a considerable financial oversight burden for procurement and financial planning teams. This tightens the dependency on a single cloud provider, increasing exposure to potential cost volatility and vendor lock-in risks, thereby raising due diligence requirements for strategic planning and resource allocation.
