Microsoft holds about 27% of OpenAI's PBC after the 2025 restructure

When OpenAI completed its recapitalization on October 28, 2025, its for-profit arm became a public benefit corporation under continued nonprofit control. Microsoft said its stake in the new entity was worth approximately $135 billion, “representing roughly 27 percent on an as-converted diluted basis,” down from the 32.5 percent it had held before recent funding rounds. As part of the same agreement OpenAI committed to buying an incremental $250 billion of Azure services, and Microsoft gave up its right of first refusal to be OpenAI’s compute provider.