Microsoft holds roughly 27% of OpenAI

The Microsoft-OpenAI relationship just got a lot less fuzzy. Microsoft’s latest 10-Q, filed on April 29 for the quarter ended March 31, 2026, says the company has “approximately 27 percent” of OpenAI on an as-converted basis and accounts for the investment under the equity method. That is the clearest plain-English disclosure yet that Microsoft is not just a strategic partner or cloud vendor — it is a very large owner. (sec.gov) ### Where did the 27% number come from? It comes from Microsoft’s quarterly filing, not rumor. The filing says Microsoft has an investment of roughly 27% of OpenAI on an as-converted basis. “As-converted” basically means you count securities as if they had already turned into common equity, which gives a better picture of real diluted ownership than a simple common-share number would. (microsoft.gcs-web.com) ### Is this a new stake? Sort of. The 27% stake was set up in the October 28, 2025 recapitalization that turned OpenAI into a public benefit corporation structure, and both OpenAI and Microsoft described the holding then as worth about $135 billion on an as-converted diluted basis. What feels new now is that the number is showing up in Microsoft’s routine public-company reporting, which makes it harder to treat the relationship as vague or informal. (openai.com) ### Why does “equity method” matter? Because that accounting treatment usually means the investor has significant influence, even without outright control. Microsoft is not consolidating OpenAI as a subsidiary, but it is also not treating the position like a passive stock bet. In plain language — this is close enough to matter financially, strategically, and in governance conversations. (microsoft.gcs-web.com) ### How much money has Microsoft actually put in? The same disclosure says Microsoft’s total funding commitment is $13 billion, with $11.8 billion funded as of March 31, 2026. Earlier filings had shown $11.6 billion funded as of September 30, 2025, so the commitment has not changed, but the funded amount has moved up. That helps explain why Microsoft’s position keeps showing up as a serious line item rather than old venture history. (om.co) ### But didn’t the partnership just loosen up? Yes — and that is what makes this interesting. On April 27, 2026, the companies said OpenAI can now serve products across any cloud provider, Microsoft’s IP license is no longer exclusive, and OpenAI’s revenue-share payments to Microsoft are now capped, though they continue through 2030. So the operating relationship got more flexible right as the ownership picture became more explicit. (cnbc.com) ### Does Microsoft still have leverage? A lot. Microsoft remains OpenAI’s primary cloud provider, keeps important IP rights through 2032, and still gets revenue share under the revised deal. So even if OpenAI can sell more freely across clouds, Microsoft still sits in three valuable places at once — owner, infrastructure provider, and economic participant. (openai. ([cnbc.com)ld anyone outside tech care? Because this is what the AI market is turning into. The biggest model companies need giant amounts of compute, and the biggest cloud companies want privileged access to the best models. That creates relationships that are not clean supplier contracts and not clean acquisitions either. They are hybrids — part financing, part distri(openai.com)ignore. (openai.com) ### So what’s the bottom line? The real news is not just that Microsoft owns roughly 27% of OpenAI. It is that the number is now sitting in a standard SEC filing while the two companies rewrite the rules of their partnership in public. Basically, the alliance is becoming less exclusive on paper but more legible in economics — and that usually matters more. (sec.gov)