OpenAI-Microsoft Deal: From 2019 to 2025, the making of one of the biggest tech partnership

In October 2025, OpenAI and Microsoft formalised a restructured partnership agreement, effectively rewriting the rules of the biggest alliances in the artificial intelligence (AI) sector. This new deal transitions OpenAI from its unique non-profit governed structure into a for-profit public benefit corporation, called OpenAI Group PBC. This entity will remain under the control of its non-profit arm, now dubbed the OpenAl Foundation. Meanwhile, Microsoft converted its massive profit-sharing rights into a 27% ownership stake in the new for-profit entity, valued at approximately $135 billion based on the company’s current $500 billion valuation.