Microsoft has signed a new agreement with OpenAI, securing a 27% stake valued at approximately $135 billion. The deal includes OpenAI's commitment to purchase an additional $250 billion in Azure services. Microsoft shares rose 4.6% in pre-market trading following the announcement. The agreement also supports OpenAI's transition to a public benefit corporation (PBC) and grants Microsoft exclusive rights to the Azure API until the development of artificial general intelligence (AGI). OpenAI will now be able to offer API access to U.S. government national security clients and publish open-weight models that meet specific capability standards.