The staff had spent the day expecting to be told of the reinstatement of Altman as CEO. Another person familiar with the matter said that over a roughly 30-minute period on Sunday night, staff members were told internally that Altman was returning, then that he wasn't, and then that Shear had been appointed. The people asked for anonymity because they were not authorized to share internal matters. Their identities are known to Business Insider.

As the staff learned of Shear's appointment, most took the news "extremely poorly," one of the people said. It was yet another shock to employees, who had been on tenterhooks all weekend.

It was left to the chief scientist and cofounder Sutskever, who helped vote Altman out and did the actual firing of him over Google Meet, to deliver the news of Shear's arrival. Sutskever appeared "subdued" during the meeting, one of the people said.

The staff, along with tech-industry observers, had wondered for days what was behind the harshly worded statement from OpenAI that said Altman "was not consistently candid in his communications with the board."

Sutskever offered two explanations that he apparently received from the board, one of the people said. One explanation was that Altman was said to have given two people at OpenAI the same project.

The other was that Altman was said to have given two board members different opinions about a member of personnel. An OpenAI spokesperson did not respond to requests for comment.

These explanations didn't make sense to employees and were not received well, one of the people said. Internally, the going theory is that this was a straightforward "coup" by the board, as it's been called inside the company and out. The person said any reason being given by the board now held little to no sway with staff.

A few hours after that meeting, an open letter was drafted, circulated among staff overnight, and signed by OpenAI leadership, including Murati and Sutskever, in which they protested the board's decision not to bring Altman back. By midday Monday, it had been signed by over 90% of the employees, according to the latest count.

In the letter, employees said they would resign if the remaining members of the board did not, if new board members were not appointed, and if Altman was not returned to the company.

At the moment, Altman is said to still be negotiating a possible return while he has an interim position at Microsoft orchestrated by CEO Satya Nadella. Microsoft is OpenAI's largest investor, with at least $10 billion put into the company.

"People are raging mad, and mass quitting is imminent," one of the people familiar with the situation said.

The company's board is made up of Quora CEO Adam D'Angelo; Tasha McCauley, a tech entrepreneur; Helen Toner of the Georgetown Center for Security and Emerging Technology; and Sutskever. Though Sutskever also signed the open letter threatening to leave the company, he is said to still technically be a member of the board. Altman and Greg Brockman, OpenAI's president, were also previously on the board.

Though Murati was a source of anger for many employees soon after Altman's ouster, given that she was his initial replacement and was said to have known he was being removed the day prior, that sentiment has cooled.

The people familiar with the events said she had "deferred" constantly to Sutskever in the immediate aftermath of Friday. Now that she's said she will leave the company should Altman not return, along with Sutskever, who also publicly expressed his "regret" for taking part in the board's move against Altman, some wonder whether all these top players could continue to work with the OpenAI team and leadership elsewhere. Others, however, say Sutskever wouldn't be easily forgiven and wouldn't be invited to stay or join a new venture at Microsoft.

Are you an OpenAI employee or someone with a tip or insight to share? Contact Kali Hays at [email protected], on the secure messaging app Signal at 949-280-0267, or through X/Twitter DM at @hayskali. Reach out using a nonwork device.