Microsoft holds 27% of OpenAI

Microsoft’s latest filings turned a long-rumored relationship into a much clearer one. The big takeaway is that Microsoft is no longer just OpenAI’s cloud partner and biggest commercial ally — it now appears to own roughly 27% of OpenAI on an as-converted basis. That matters because the Microsoft-OpenAI deal was already unusual. Now it looks less like a supplier contract with side perks and more like a deeply entangled financial structure. ### Where does the 27% number come from? It comes from Microsoft’s own disclosures. In its fiscal Q2 2026 10-Q, filed on January 28, 2026, Microsoft said it had “approximately 27 percent of OpenAI on an as-converted basis” and that the stake is accounted for under the equity method. That phrasing matters. It means Microsoft is treating OpenAI less like a passive bet and more like a large strategic holding whose gains and losses can flow through Microsoft’s own results. ### Why is “as-converted” doing so much work? Because this is not a simple common-stock ownership number. “As-converted” usually means you are counting preferred shares, convertible instruments, and other rights as if they had already turned into ordinary equity. Basically, it is the fully diluted view — the version investors use when they want to know what everyone would own if all the paper promises became actual shares. So the 27% figure is not just a casual estimate. It is the cap-table version that matters most for economics and control. ### Did something change recently? Yes — the partnership itself was rewritten on April 27, 2026. Microsoft and OpenAI jointly said they amended the deal to add “long-term clarity.” OpenAI can now sell its products across any cloud provider, while Microsoft remains the primary cloud partner and keeps a license to OpenAI IP through 2032. That license is now non-exclusive. Microsoft also no longer pays a revenue share to OpenAI, while OpenAI continues paying Microsoft through 2030 at the same percentage, now with a cap. ### So is Microsoft gaining or losing power? Both, in different ways. Microsoft lost exclusivity. That is real. OpenAI can now work more openly with Amazon Web Services and Google Cloud customers, which removes a major bottleneck in enterprise sales. But Microsoft gained predictability. It still gets first access on Azure in many cases, keeps long-dated IP rights, and sits inside OpenAI’s upside as a major shareholder. In other words, Microsoft gave up some control over distribution but locked in a cleaner claim on economics. ### Why would OpenAI agree to that? Because OpenAI needs two things at once — more freedom and absurd amounts of compute. The old arrangement helped it scale fast, but it also limited where it could sell and deploy. The amended deal loosens that constraint while preserving the infrastructure relationship that still matters most. Reuters also reported that OpenAI’s commitment to use at least $250 billion in Azure services by 2032 remains in place, which shows how dependent the company still is on Microsoft’s datacenter muscle even as it broadens distribution. ### Why are Microsoft investors paying attention now? Because OpenAI is starting to hit Microsoft’s income statement in a visible way. Microsoft’s January 28, 2026 earnings materials showed a $7.6 billion gain from its OpenAI investment in fiscal Q2, after a $3.1 billion hit in fiscal Q1. Once a stake this large moves under equity accounting, OpenAI stops being just a strategic story and starts becoming a material financial variable for Microsoft shareholders. ### What’s the real bottom line? The 27% stake does not mean Microsoft owns OpenAI in the normal sense. But it does mean the two companies are tied together more tightly than the old “partner and customer” framing suggested. OpenAI got room to breathe. Microsoft gave up exclusivity. Yet the revised structure still leaves Microsoft with a huge economic interest, durable product rights, and a central role in the compute stack. Basically, they loosened the marriage contract without actually separating.