Background
Samuel Harris Altman was born on 22 April 1985. He was president of Y Combinator before becoming chief executive of OpenAI, and his wealth has an unusual shape for someone in that position: it comes almost entirely from investments made alongside the job rather than from the company he runs.
No Equity in OpenAI
Altman holds no direct equity in OpenAI. This is not a technicality about vesting or structure – it is the position he has stated publicly and which a court filing has since documented. Where a founder-chief executive of a company of that scale would normally hold a stake worth tens of billions, his is nil.
The reason usually given is governance: OpenAI’s structure was designed so that the person running it would not have a personal financial interest in its returns. Whatever the merit of that argument, it means his fortune has to be found elsewhere.
What the Filing Showed
A May 2026 court filing disclosed his holdings in nine private companies that had dealings with OpenAI, together worth more than $2 billion as at a 31 December 2025 valuation date. Reuters The largest by a wide margin was the fusion company Helion Energy at about $1.7 billion, followed by Stripe at roughly $633 million and Retro Biosciences at about $258 million, with a small Cerebras position and several others.
One point deserves care, because the reporting has been inconsistent. Altman built a large Reddit position – about 12.2 million shares – and that holding has been described in 2026 coverage as still worth around a billion dollars. The Motley Fool The court filing, however, indicates the stake had been sold by the end of 2025. The two accounts cannot both be current, and the filing is the better-evidenced of the two.
How the Estimate Is Calculated
The arithmetic. Start from the $2 billion-plus disclosed in the filing (Reuters), which covers only those companies with an OpenAI relationship and is therefore a floor rather than a total. Add holdings with no OpenAI connection, which the filing had no reason to list, and any proceeds from the Reddit disposal. Published estimates put him around $4 billion, which implies roughly as much again outside the disclosed set. These are broad assumptions rather than accounting: private company valuations move sharply and are marked at a point in time, and a December 2025 valuation of a fusion startup is not a price anyone has been paid.
Estimated Net Worth
Disclosed floor: over $2 billion as at 31 December 2025. Commonly cited total: around $4 billion. His stake in OpenAI itself, the company that made him famous: none.