70% of Microsoft's AI Revenue — $24B a Year — Comes From OpenAI

Bloomberg has done the math: 70% of Microsoft's AI revenue comes from OpenAI — $24.1 billion for the fiscal year ending June 2026. The company's total AI business runs at roughly $37 billion a year. Meanwhile, Satya Nadella is publicly beating the drum for open models and warning against a "monopoly of a few proprietary AIs" — the company that made vendor lock-in famous is now fighting a serious lock-in of its own.

When the largest AI infrastructure provider earns 70% of its AI revenue from a single supplier, that's not a partnership — it's a vulnerability. Microsoft is quietly replacing OpenAI models in Office with its own in-house alternatives: for this company, open models aren't about ideology. They're about de-risking a $24 billion bet.