Sam Altman is to return as chief executive of OpenAI days after being fired from the ChatGPT creator.

OpenAI has also agreed to change the board that ousted him after the majority of employees threatened to quit over the decision unless Altman was reappointed.

The company said: “We have reached an agreement in principle for Sam Altman to return to OpenAI as chief executive with a new initial board of Bret Taylor (chairman), Larry Summers, and Adam D’Angelo.”

Bret Taylor is the former Salesforce co-chief executive and Larry Summers is the former US Treasury secretary. Adam D’Angelo, the chief executive of the answers site Quora, was part of the board that ousted Altman.

OpenAI announced the changes in a post on X, formerly Twitter, saying: “We are collaborating to figure out the details.”

Sam Altman, 38, said on X: “I love OpenAI, and everything I’ve done over the past few days has been in service of keeping this team and its mission together. When I decided to join Microsoft on Sunday evening, it was clear that was the best path for me and the team. With the new board and with Satya’s support, I’m looking forward to returning to OpenAI, and building on our strong partnership with Microsoft.”

Satya Nadella, the Microsoft chief executive, hired Altman to lead the software company’s new advanced AI research team, along with OpenAI’s former president Greg Brockman and other staff. The decision had been seen as a coup for Microsoft.

The loss of key staff and the petition signed by 700 of OpenAI’s 770 staff calling for the board to go and for Altman to be reinstated as its boss had left the company in a deep crisis.

Employees, investors and even the new interim chief executive Emmett Shear, the former chief executive of Twitch, spoke out against the way in which OpenAI’s executive committee had handled the situation, as the reason for ousting Altman remained a mystery.

When he was ousted on Friday, four board directors said in a blog post that Altman had not been “consistently candid” with board members, without elaborating.

The Verge, the technology news website, said that the new board would vet and appoint a board of up to nine people that would reset the governance of OpenAI. It added that Microsoft, which has invested more than $10 billion into OpenAI, wanted a seat on the expanded board, as did Altman himself.

The new website The Information reported that neither Altman nor Brockman would reclaim their seats on the board. It said that Altman had agreed to an internal investigation into alleged conduct that prompted the board to oust him.

Thrive Capital, an investor in OpenAI, said that the reinstatment of Altman was “the best outcome for the company, its employees, those who build on their technologies, and the world at large.”