Mira Murati, chief technology officer at OpenAI, the San Francisco-based makers of ChatGPT, along with the company’s chief research officer Bob McGrew and vice president of research Barret Zoph, resigned on Wednesday afternoon.

Murati announced her resignation after six-and-a-half years with the leading artificial intelligence company, in a statement to Open AI staff that she also shared on X.

“I’m stepping away because I want to create the time and space to do my own exploration,” she said in the post. “This moment feels right.”

CEO Sam Altman replied to the post, thanking Murati and adding that the company will say more about its transition plans soon.

A few hours later, Altman announced, in a note to OpenAI staff shared on X, that McGrew and Zoph had also resigned. He said the departures of McGrew, Zoph, and Murati were amicable and were made independently of one another.

“The timing of Mira’s decision was such that it made sense to now do this all at once, so that we can work together for a smooth handover to the next generation of leadership,” Altman said.

Altman also named Mark Chen as the new senior vice president of research and Matt Knight as the chief information security officer, in a slew of new appointments in the company’s leadership roles.

Altman said he has spent most of his time in the past year on the non-technical side of the company but plans to shift his focus to the technical and production side.

“Leadership changes are a natural part of companies, especially companies that grow so quickly and are so demanding,” he said on X. “I obviously won’t pretend it’s natural for this one to be so abrupt, but we are not a normal company.”

In August, OpenAI co-founder John Schulman said on X that he had joined rival AI company Anthropic and another co-founder, Greg Brockman, also said on X he was taking a sabbatical through the end of the year. A third co-founder, chief scientist Ilya Sutskever, left OpenAI in May.

OpenAI ousted Altman in November 2023 over a breakdown in communication and loss of trust. He was reinstated five days later after Microsoft hired him. At the time, Microsoft had since 2018 invested more than $10 billion in OpenAI.

OpenAI was founded in 2015 as a nonprofit but added the for-profit OpenAI LP as a subsidiary in 2018, at which point OpenAI cofounder Elon Musk left the company.