“Mr. Altman’s departure follows a deliberative review process by the board, which concluded that he was not consistently candid in his communications with the board, hindering its ability to exercise its responsibilities,” the company said in its blog post. “The board no longer has confidence in his ability to continue leading OpenAI.”

Chief technology officer Mira Murati will be the interim CEO, effective immediately. The company will be conducting a search for the permanent CEO successor. When contacted by The Verge, OpenAI’s communications department declined to comment beyond the blog post. Employees at OpenAI found out about the news when it was announced publicly, according to multiple sources.

“I loved my time at OpenAI,” Altman said in a post on X (formerly Twitter). “It was transformative for me personally, and hopefully the world a little bit. Most of all I loved working with such talented people. Will have more to say about what’s next later.”

Microsoft, which has invested billions in OpenAI, tells The Verge it will continue to partner with the company. “We have a long-term partnership with OpenAI and Microsoft remains committed to Mira and their team as we bring this next era of AI to our customers,” according to a statement sent by Microsoft spokesperson Frank Shaw.

OpenAI also announced that co-founder Greg Brockman will be stepping down as chairman of the board, though he will remain at the company.

Tom Warren and Alex Heath contributed reporting.

Update November 17th, 4:50PM ET: Added X post from Altman.