Sam Altman, the Silicon Valley CEO behind the artificial intelligence-powered chatbots ChatGPT and GPT-4, has been abruptly fired by his company’s board of directors in a major shakeup for the tech industry.

Microsoft-backed OpenAI said on Friday that its board of directors decided on the “leadership transition” after losing confidence in Altman’s ability to lead the company.

“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 a statement on its blog.

The board of directors said they were grateful for Altman’s contributions but had decided that “new leadership is necessary as we move forward”.

The company or its board did not elaborate on the reason for Altman’s departure.

Chief Technology Officer Mira Murati was appointed interim CEO until a more permanent replacement is found to lead the $90bn company.

Altman represented the company just this week in a panel discussion at the Asia-Pacific Economic Cooperation forum in San Francisco.

In a post on X, formerly Twitter, shortly after the announcement, Altman said he “loved working with such talented people” and that leading the company had been “transformative to me personally”.

Altman said in later posts on X that his firing was a “weird experience” and “sorta like reading your own eulogy while you’re still alive,” and that “if I start going off, the OpenAI board should go after me for the full value of my shares.”

Unlike other tech founders such as Mark Zuckerberg, Altman did not have equity in OpenAI and could be fired at any time, the news site Semafor reported earlier this year.

Altman’s surprise departure prompted a flurry of reactions across the tech sector.

Former Google CEO Eric Shmidt on X described Altman as a “hero” who had “changed our collective world forever”.

OpenAI president Greg Brockman, who co-founded the start-up with Altman and Elon Musk, announced shortly after the news broke that he would also be leaving the company.

“We’ve been through tough and great times together, accomplishing much despite the reasons it should have been impossible, but based on today’s news, I quit,” he said on X.

Three senior researchers also resigned on Friday night, the tech news site The Information reported, citing several people with knowledge of the situation. Altman became a household name following last year’s release of ChatGPT, which captivated and alarmed the public in equal measure with its ability to provide lengthy and human-like – but not always accurate – answers to user queries.

In September, New York Magazine published a profile comparing the tech entrepreneur to J Robert Oppenheimer – known as the father of the atomic bomb – and Time Magazine included him on its list of the 100 most influential people in AI in 2023.