OpenAI’s IPO talks put Microsoft’s stake back in focus, as markets weigh a potential $1 trillion valuation

OpenAI, the maker of ChatGPT, has reportedly taken steps toward going public, raising the stakes for Microsoft, which holds one of the largest financial positions in the AI firm. A recent report said OpenAI is headed toward an initial public offering that could reach a $1 trillion valuation, and pointed to Microsoft as the biggest listed-company beneficiary of the upside if the numbers hold.

The same reporting ties Microsoft’s exposure to the terms of OpenAI’s corporate restructuring and its relationship to Microsoft’s cloud services. When OpenAI reorganized into a public benefit corporation in 2025, Microsoft disclosed that its investment represented roughly 27% of OpenAI on an as-converted, diluted basis, valued at about $135 billion at the time the deal was described. The report also said the arrangement included extended rights to OpenAI’s technology through 2032 and an expectation that OpenAI would purchase an additional $250 billion of Azure services.

OpenAI has not, in the available reporting, provided details on timing or valuation directly in a public announcement. However, the report said OpenAI confirmed that it filed confidential IPO paperwork in June with the U.S. Securities and Exchange Commission. Separately, Reuters has reported that OpenAI filed for a U.S. IPO after Anthropic, framing the move as part of a broader wave of large AI companies preparing for public markets.

On valuation, the reporting described a potential target of a $1 trillion or higher market cap and suggested an IPO window that could stretch toward 2027. That matters for Microsoft because the firm’s stake would likely be marked to whatever the eventual public-market price implies. Even if Microsoft’s ownership percentage does not change, the dollar value of the position would, in effect, move with the IPO valuation.

Microsoft’s current market performance is also part of the story as investors compare its stock price to the private valuation implied by OpenAI. The coverage said Microsoft stock is down about 19% for the year and trades roughly 30% below its 52-week high, while the company continues to report revenue growth. The point in the reporting was not that Microsoft has already monetized OpenAI’s IPO, but that the market may be discounting Microsoft’s AI-linked optionality relative to the embedded value of its stake.

For readers, the key mechanics are straightforward. The IPO would create a public price for shares in OpenAI, turning a largely private valuation into an observable market figure. Microsoft’s roughly quarter-share economic interest means that a higher public-market valuation could boost the perceived value of that position, while any valuation weakness could do the opposite. The cloud-service commitment also remains relevant because it connects the companies’ economics beyond the IPO, linking OpenAI’s compute needs to Microsoft’s Azure revenue potential.

Still, significant uncertainty remains. Confidential filings are not the same as approved terms, and companies can change offering size, share structure, pricing range, or timing as regulators, underwriters, and markets respond. In addition, the $1 trillion valuation figure is presented in the reporting as a leaning target, not as a disclosed, finalized IPO term. Until OpenAI and its advisers issue clearer disclosures, the precise path to an IPO, as well as what portion of the company’s shares would be sold and at what price, is not verifiable from the available text.

Looking ahead, investors and industry watchers will likely focus on whether OpenAI makes its confidential filing public, what valuation range it indicates, and whether the IPO competes or coordinates with other major AI listings already in the pipeline. For Microsoft, the next checkpoint may be any additional disclosure tied to its OpenAI position, the Azure service commitment, and any changes in the pace of AI compute consumption that could influence how investors underwrite the relationship even before the IPO occurs.