Y Combinator’s Stake in OpenAI

Monday, 4 May 2026

Speaking of companies with valuable minority stakes in AI companies, there’s one thing that stuck in my craw about the blockbuster Ronan Farrow / Andrew Marantz investigative piece on Sam Altman and OpenAI last month for The New Yorker. It didn’t come up during Nilay Patel’s excellent interview with Farrow on Decoder, either.

Sam Altman was the president of Y Combinator for several years, and left to become the full-time CEO of OpenAI. The New Yorker quotes Y Combinator co-founder Paul Graham multiple times, in the context of Altman’s trustworthiness. (Some of those quotes are firsthand, others secondhand.) Graham’s role in the story — particularly his public remarks after publication — comprised an entire section in my own take on the New Yorker piece, wherein I concluded:

I would characterize Graham’s tweets re: Altman this week as emphasizing only that Altman was not fired or otherwise forced from YC, and could have stayed as CEO at YC if he’d found another CEO for OpenAI. But for all of Graham’s elucidating engagement on Twitter/X this week regarding this story, he’s dancing around the core question of the Farrow/Marantz investigation, the one right there in The New Yorker’s headline: Can Sam Altman be trusted? “We didn’t ‘remove’ Sam Altman” and “We didn’t want him to leave” are not the same things as saying, say, “I think Sam Altman is honest and trustworthy” or “Sam Altman is a man of integrity”. If Paul Graham were to say such things, clearly and unambiguously, those remarks would carry tremendous weight. But — rather conspicuously to my eyes — he’s not saying such things.

The thing that stuck in my craw is this: Does Y Combinator own a stake in OpenAI? And if they do, given OpenAI’s sky-high valuation, isn’t that stake worth billions of dollars?

OpenAI was seeded by an offshoot of Y Combinator called YC Research in 2016 — when Altman was running YC. In December 2023, the well-known AI expert (and AI-hype skeptic) Gary Marcus wrote the following, in a piece on Altman’s trustworthiness in the wake of the OpenAI board saga that saw Altman fired, re-hired, and the board purged in the course of a tumultuous week:

After poking around, I found out that “I have no equity in OpenAI” was only half the truth; while Altman to my knowledge holds no direct equity in OpenAI, he does have an indirect stake in OpenAI, and that fact should have been disclosed.

In particular, he own a stake of Y Combinator, and Y Combinator owns a stake in OpenAI. It may well be worth tens of millions of dollars; even for Altman, that’s not trivial. Since he was President of Y Combinator, and CEO of OpenAI; he surely was aware of this.

So it’s well known that Y Combinator owns some stake in OpenAI. But how big is that stake? This seems like devilishly difficult information to obtain. I asked around and a little birdie who knows several OpenAI investors came back with an answer: Y Combinator owns about 0.6 percent of OpenAI. At OpenAI’s current $852 billion valuation, that’s worth over $5 billion.

Graham and his wife Jessica Livingston are two of Y Combinator’s four founding partners. The fact that Paul Graham personally has billions of dollars at stake with OpenAI doesn’t mean that his public opinion on Sam Altman’s trustworthiness and leadership is invalid. But it certainly seems like the sort of thing that ought to be disclosed when quoting Graham as an Altman character reference. A billion dollars here, a billion there — that adds to up the sort of money that might skew a fellow’s opinion.