• The declaration came at the conclusion of an eventful weekend for OpenAI, following Mr. Altman’s efforts to retake his position as the company’s chief executive officer.

The board of directors of OpenAI, a rapidly growing artificial intelligence start-up, said in a message to staff on Sunday night that Sam Altman, the company’s previous CEO, would not be coming back to work. They also named Altman’s second temporary successor in as many days.

A few hours later, Microsoft made another shocking announcement: it was employing both Mr. Altman and Greg Brockman, the president of OpenAI and a co-founder of the business who resigned in support of Mr. Altman. The two guys will be in charge of Microsoft’s cutting-edge research center.

The board announced that Emmett Shear, a former Twitch CEO, will take Mira Murati’s position as acting CEO of OpenAI. Longtime OpenAI executive Ms. Murati was named to that position following Mr. Altman’s dismissal on Friday. As to the document obtained by The New York Times, the board stated that Mr. Shear had a “unique mix of skills, expertise, and relationships that will drive OpenAI forward.”

In apparent contrast to the OpenAI board’s call for prudence in the development of A.I. technology, Microsoft CEO Satya Nadella said that Mr. Altman will lead the new research facility and “set a new pace for innovation.” In a post on X, the old Twitter, Mr. Nadella stated that Mr. Altman’s new team will function independently within Microsoft.

Other anonymous coworkers who could join the two co-founders at Microsoft are allowed to join, according to Mr. Nadella. “We’re eager to get started on giving them the tools they need to succeed,” he remarked.

In a cryptic response, Mr. Altman wrote on X, “the mission continues.” By Monday morning, according to three individuals who saw the letter, over 550 of OpenAI’s 700 workers had signed it threatening to leave the start-up to work on Mr. Altman’s new project at Microsoft unless the board resigned.

Microsoft’s spokesperson declined to comment on anything more than Mr. Nadella’s tweets to X. Wired has previously reported on the letter.

The IT community, as well as investors in OpenAI including Microsoft, Sequoia Capital, and Thrive Capital, were taken aback by Mr. Altman’s dismissal. One minute before it was made public, Microsoft, which has invested over $13 billion in OpenAI, was unaware of Mr. Altman’s departure; other investors found out via social media that he had been ejected. Over the weekend, they received no updates or more information.

The message on Sunday made reference to Mr. Altman’s dismissal from the business on Friday, saying that “the board firmly stands by its decision as the only path to advance and defend the mission of OpenAI.” All four of the company’s directors—Adam D’Angelo, Helen Toner, Ilya Sutskever, and Tasha McCauley—signed it.

In other words, the board’s capacity to properly oversee the firm in the way it was required to do so was compromised by Sam’s activities and his lack of openness in his meetings with the board, the letter stated.

A divide in the artificial intelligence field has also been highlighted by the departure of Mr. Altman, 38. There are many who think that A.I. is the most significant technological advancement since web browsers, while others fear that developing the technology too quickly might be hazardous. Mr. Sutskever, in particular, was concerned that Mr. Altman was neglecting the risks associated with artificial intelligence in favor of expanding OpenAI’s company.

The board’s decision to fire Mr. Altman shocked supporters of the charismatic founder as well as industry friends. Tech executives and investors in Silicon Valley backed Mr. Brockman and Mr. Altman. By Friday night, Mr. Altman was selling investors on a new artificial intelligence start-up, which he intended to launch alongside Mr. Brockman.

Artificial intelligence has captivated the public’s attention since OpenAI debuted its popular ChatGPT chatbot over a year ago. People are hoping that AI will be utilized for meaningful tasks like medication research or to assist in teaching young people. However, some political figures and AI experts are concerned about the potential consequences of AI, such as the automation of labor and the escalation of autonomous conflict beyond human control.

Along with its previous CEO, who has done more than anybody in the past year to bring artificial intelligence into the public eye, OpenAI has been the focal point of that conversation.

The board removed Mr. Altman without mentioning any particular instances involving him. Rather, it stated that Mr. Altman was “necessary to preserve the board’s ability to execute its responsibilities and advance the mission of this organization” and that he had “lost the trust of the board of directors.”

The memo stated that “any C.E.O. must be honest and transparent with his or her board.”

Requests for response from OpenAI and Mr. Altman were not immediately answered.

Over the course of the weekend, venture capitalists, other tech CEOs, and staff members urged Mr. Altman and his allies to put pressure on the OpenAI board. According to three sources, Microsoft spearheaded the initiative, and smaller investors used Microsoft as a conduit for their grievances.

According to the sources, the purpose of the endeavor was to demonstrate to the board of the firm how well-liked Mr. Altman was among the staff at OpenAI and throughout Silicon Valley.

The absence of information on the grounds for Mr. Altman’s dismissal gave his followers more confidence. There were others who contended that the nonprofit board of OpenAI was unable to sustain the company that OpenAI had grown into, with 700 staff members, several clients, corporate alliances, and an estimated $1 billion in income each year.

In 2015, Mr. Altman, Mr. Brockman, and Mr. Sutskever founded OpenAI with nine other people, including Tesla CEO Elon Musk. In contrast to Google and other digital behemoths, the group said when they established the A.I. lab that it would not be motivated by financial gain.

Following Mr. Musk’s departure from OpenAI in 2018, Mr. Altman converted the lab into a for-profit business under the nonprofit’s and its board’s direction. He raised the billions of dollars the business needed to develop technologies like ChatGPT over the course of the following few years.

Prior to joining OpenAI, Mr. Shear oversaw Twitch’s growth from a fledgling website known as Justin.tv to a massive company that was bought by Amazon in 2014. He continued to work there after the internet giant acquired the company, leaving until early this year to announce the birth of his kid.

Although he had his detractors, Mr. Shear, a lifelong player of video games, was seen as a capable leader at Twitch. It was thought that he was overly preoccupied with reducing expenses and making the financially unsuccessful website viable.

The board wrote in its email, “We apologize for the abruptness of the process that we felt was required by the situation.” “We continue to believe that our actions were necessary, even in light of the questions it has raised.”

One name jumped out on Monday when OpenAI staff members signed the letter indicating they would quit to work on Mr. Altman’s new project at Microsoft: Mr. Sutskever. He sent X a message on social media expressing his great contrition for his part in the board’s decision.

He declared, “I never intended to harm OpenAI.” “I will stop at nothing to bring this company back together because I love everything we’ve built together.”