The Foundation Still Controls the Board
OpenAI is not a normal company. It started as a nonprofit in 2015, reorganized into a capped-profit hybrid in 2019, and completed its latest transformation in October 2025 when it became a public benefit corporation called OpenAI Group PBC.
At the time of recapitalization, the OpenAI Foundation held roughly 26% of the PBC. Later financing rounds may have diluted that percentage, but the Foundation retained special governance rights. It appoints every board member and can remove any of them at any time. That governance structure survived the restructuring. It means no single investor, including Microsoft, controls strategic direction.
Sam Altman, the CEO, owns 0% equity. For a founder running a company valued north of $800 billion, that is virtually unprecedented in tech history.
Microsoft Is the Largest Single Investor
According to reported cap-table estimates, Microsoft holds roughly 26.79% of OpenAI on a fully diluted basis. The company invested roughly $13 billion starting in 2019 and that stake would be worth approximately $228 billion at the March 2026 valuation. That is a 17.6x return on paper.
Microsoft trades at around $419 per share with a market cap near $3.1 trillion and a forward P/E of roughly 25. The OpenAI stake represents about 7.4% of Microsoft's total market value. It is meaningful but not existential. Microsoft's Azure cloud business generates its own AI revenue through the OpenAI partnership, which adds another layer of value beyond the equity stake itself.
The conversion from profit-capped interest to straight equity happened during the PBC restructuring. Microsoft now holds conventional shares, the same kind any public market investor would own after the IPO.
SoftBank Built the Biggest Position in One Year
SoftBank committed $64.4 billion to OpenAI across multiple tranches, giving it a reported 13% ownership stake. The Vision Fund reported the fair value of its OpenAI holdings at $79.6 billion by the end of fiscal year 2025, representing a $45 billion gain within a single year as OpenAI's valuation climbed from $157 billion to $852 billion.
SoftBank trades on the Tokyo Stock Exchange under ticker 9984 and over-the-counter in the US as SFTBY. SoftBank is also reportedly seeking a $10 billion margin loan backed by its OpenAI shares. That tells you how central this single position has become to the entire SoftBank portfolio.
Amazon and Nvidia Paid for Access, Not Just Equity
Amazon invested $50 billion in the February 2026 funding round, with $15 billion upfront and another $35 billion conditional on milestones. The deal came paired with an expanded $100 billion cloud infrastructure agreement through AWS over eight years. Amazon is buying a relationship, not just shares.
Nvidia put in $30 billion. OpenAI committed to using 3 gigawatts of dedicated inference capacity and 2 gigawatts of training on Nvidia's Vera Rubin systems as part of the arrangement. Nvidia's investment guarantees its hardware stays at the center of OpenAI's compute stack.
Neither company disclosed an exact ownership percentage, but at the $852 billion valuation their combined $80 billion would represent roughly 9-10% before dilution.
Early Investors Are Sitting on Generational Returns
The earliest backers of OpenAI's for-profit division in 2019, including Khosla Ventures, Reid Hoffman, and Y Combinator, collectively put in $194 million. That pool is now worth an estimated $5 billion, roughly a 25x return.
Thrive Capital led the October 2024 Series E with about $1.2 billion at a $157 billion valuation. At the current $852 billion figure, that position has more than quintupled in under two years.
Peter Thiel's Founders Fund, one of the earliest investors, is reportedly looking at projected returns exceeding 140x on its initial stake. Andreessen Horowitz co-led the $122 billion March 2026 round alongside Amazon, SoftBank, and Nvidia.
Employees reportedly hold a combined 19% through stock grants and options, according to leaked cap-table estimates. That block will be significant once the IPO creates liquidity.
The IPO Math Is Brutal
OpenAI is reportedly preparing to file confidential IPO paperwork with the SEC, with Goldman Sachs and Morgan Stanley working on the draft prospectus. The company is targeting a potential September 2026 listing at a valuation between $852 billion and $1 trillion, though timing could still change.
The revenue numbers are real. OpenAI exited 2025 above a $20 billion annualized run rate. By early 2026, monthly revenue was running around $2 billion. The company counts 50 million consumer subscribers and 9 million business users.
The losses are also real. Reported estimates suggest OpenAI remains deeply loss-making, with compute and infrastructure spending scaling faster than revenue. Projected 2026 losses are estimated around $14 billion. That is the tradeoff of building out AI infrastructure at a pace that dwarfs anything the tech industry has attempted before.
At an $852 billion valuation on roughly $25 billion in annualized revenue, the price-to-sales ratio is about 34x. For context, Nvidia posted $81.6 billion in revenue in a single quarter, generates net margins above 50%, and trades at a trailing price-to-sales ratio of roughly 27x. OpenAI is asking for a higher multiple while burning cash.
How Retail Investors Can Get Exposure Now
OpenAI is not publicly traded yet. The September listing is still months away and the S-1 details remain sealed until roughly 15 days before the roadshow.
The most direct publicly traded exposure is Microsoft, which holds the largest stake at roughly 27%. Every dollar OpenAI gains in value adds roughly 27 cents to Microsoft's balance sheet. At a P/E of 25 and a yield on Azure's AI revenue stream, Microsoft offers the cleanest proxy.
Beyond individual stocks, the Fundrise Innovation Fund (ticker VCX) holds a 9.9% allocation to OpenAI and is available to non-accredited investors with a $10 minimum. ARK Venture Fund also holds a position across a portfolio of 68 private and public companies. These are not clean OpenAI proxies. They carry fund-level fees, limited liquidity, valuation lag on private holdings, and exposure to many other companies besides OpenAI. For accredited investors, secondary platforms like Forge Global and Hiive facilitate pre-IPO share purchases from existing shareholders.
The other major investors, Amazon and Nvidia, both own meaningful stakes but their OpenAI positions represent a small fraction of their total market caps. Amazon's $50 billion commitment is under 2% of its roughly $2.8 trillion valuation. Nvidia's $30 billion is well under 1% of its roughly $5.4 trillion market cap.
What Changes When the S-1 Goes Public
The sealed S-1 will eventually reveal the full cap table, exact revenue trajectory, cost structure, and risk factors. Until then, the ownership picture described here is based on the leaked cap table and disclosed funding round terms.
Three things to watch. First, whether Microsoft's 27% stake gets diluted by the IPO itself, and by how much. Second, whether SoftBank's margin loan against its shares creates forced selling risk if the stock drops post-listing. And third, whether the employee 19% block creates immediate selling pressure once the lockup expires, typically 90 to 180 days after the IPO.
OpenAI is racing toward the public markets at a trillion-dollar valuation, losing money on every dollar of revenue, and backed by the largest single-company investor syndicate ever assembled. The ownership structure will matter as much as the product once public shareholders have a vote.
