The future of OpenAI is in jeopardy after more than 700 of its 770 employees signed a letter Monday saying they may leave the company for Microsoft if the ousted CEO, Sam Altman, is not reinstalled at the high-profile artificial intelligence startup.

One of the board members who pushed out Altman on Friday reversed course Monday and signed the letter, which was on an internal message board, according to three people familiar with the matter.

The board member, Ilya Sutskever, also posted on the social media platform X, formerly Twitter, that “I deeply regret my participation in the board’s actions.”

The ouster of Altman by the four-member board — which said he had not been candid with it but did not say how — set off a frantic weekend of corporate jockeying in which Altman wound up joining Microsoft to start a new AI project. Microsoft, which has invested $13 billion in OpenAI, essentially has a 49% stake in the company.

The staff’s letter demanding Altman’s reinstatement said Microsoft had assured OpenAI employees that there were positions for them all if they chose to join its new AI subsidiary.

OpenAI and Microsoft declined to comment. Emmett Shear, whom the OpenAI board named as interim CEO late Sunday, told a reporter Monday that he could not comment because he was on another call.

The upheaval leaves the future of one of the fastest-growing companies in Silicon Valley history in doubt. At a time when the industry was reeling in the wake of mass layoffs, OpenAI’s technology fueled the creation of hundreds of startups. Now, many of those businesses are concerned about their prospects.

“This is the debacle of the decade,” said Gaurav Oberoi, the founder of Lexion, a startup that relies on OpenAI to help companies streamline legal, sales and vendor contracts. “It’s a lesson in how to destroy a huge amount of value overnight and their own reputation.”

Early Monday, in a 530-word post on X, Shear said he planned to hire an independent investigator to review the details before and after Altman’s dismissal. He also committed to gathering insight from employees, partners and investors that he said would inform how he rebuilds the company’s leadership team.

“I believe it may take longer than a month to achieve true progress,” said Shear, the former CEO of the livestreaming site Twitch. Later that day, Shear spoke with Microsoft CEO Satya Nadella.

The New York Times News Service