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 shake-up for the tech industry.

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

Open AI 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.