Mira Murati’s startup, Thinking Machines Lab, is losing two of its co-founders to OpenAI

Former OpenAI director Mira Murati’s startup, Thinking Machines Lab, is saying goodbye to two of its co-founders, both returning to OpenAI. Another former OpenAI employee who went on to work for Murati’s startup is also returning to the company.

On social media, Murati announced the departure of Barret Zoph, the company’s co-founder and CTO, on Wednesday. “We said goodbye to Barret,” Murati said in a message on X. “Soumith Chintala will be the new CTO of Thinking Machines. He is a brilliant and seasoned leader who has made significant contributions to the AI ​​field for more than a decade, and he has been a key contributor to our team. We couldn’t be more excited to have him take on this new responsibility.”

Murati’s announcement made no mention of co-founder Luke Metz or other departures.

Just 58 minutes after Murati’s announcement of Zoph’s departure, OpenAI Applications CEO Fidji Simo announced that Zoph would be returning to OpenAI. “I’m happy to welcome Barret Zoph, Luke Metz and Sam Schoenholz back to OpenAI! This has been in the works for several weeks and we’re excited to have them join the team,” Simo wrote on X.

Metz, who is co-founder from Thinking Machines, previously worked for OpenAI several years on the company’s technical staff. Schönholz did that too, whose LinkedIn profile still mentions that he works for Thinking Machines.

Zoph previously worked for OpenAI as VP of research and previously spent six years at Google as a research scientist. Murati, who served as CTO of OpenAI until September 2024, left the company and co-founder of Thinking Machines with Zoph and Metz. The startup, where Murati is CEO, has since amassed significant funding, closing a $2 billion seed round last July, with participation from Andreessen Horowitz, who led the round, as well as Accel, Nvidia, AMD and Jane Street, among others. The round valued the company at $12 billion.

TechCrunch has reached out to both Thinking Machines and OpenAI for comment.

While talent changes between AI giants are common in Silicon Valley, the departure of a startup’s co-founders less than a year after its founding is particularly notable. Losing two co-founders at once – especially when one was serving as CTO – could be seen as a particularly meaningful setback for Thinking Machines, which had assembled a high-profile team of former OpenAI, Meta, and Mistral AI researchers.

The company has also lost other key staff, including co-founder Andrew Tulloch, who left for Meta in October. OpenAI itself has seen numerous co-founders leave to launch or join competing ventures, including John Schulman, who left for Anthropic in August 2024 before joining Thinking Machines Lab as Chief Scientist at its launch last February.