Mira Murati’s Thinking Machines Lab Takes Talent Hit, Two Cofounders & Researcher Rejoin OpenAI

Former OpenAI CTO Mira Murati’s high-profile startup, Thinking Machines Lab, lost two of its co-founders on Wednesday after OpenAI announced the rehiring of Barret Zoph and Luke Metz. OpenAI also confirmed the return of researcher Sam Schoenholz. The moves were confirmed publicly by OpenAI applications chief Fidji Simo and in posts from people close to the companies.

Murati posted on X that the company “has parted ways with Barret” and that Soumith Chintala, the PyTorch co-creator and long-time AI engineer, will step in as Thinking Machines’ new chief technology officer. Minutes after Murati’s message, Fidji Simo posted that Zoph, Metz and Schoenholz would be “welcome[d] back” to OpenAI, saying the hires had been in the works for weeks.

Talent Swing

The exits come as a striking development for a startup that raised a blockbuster seed round last year. Thinking Machines closed about $2 billion in funding in mid-2025 in a round led by Andreessen Horowitz and was reported at valuations in the $10–$12 billion range, underscoring how much investor capital and market attention the firm has attracted. Losing two co-founders, including the outgoing CTO, is likely to prompt questions about near-term execution and leadership continuity.

The episode highlights how fiercely contested senior AI talent remains between top labs. Thinking Machines was built around a roster of ex-OpenAI researchers and promises collaborative multimodal systems; OpenAI’s ability to re-secure experienced researchers strengthens its research bench while complicating Murati’s effort to scale a rival team. Industry analysts say rapid moves like these, hires, departures and quick returns, are now a common feature of the AI labour market and can shift project road maps and timelines.

Company Statement

OpenAI’s announcement came via Simo’s public post; Thinking Machines’ public comment was limited to Murati’s X post about Zoph and the naming of Chintala as CTO. Tech outlets report they have reached out to both companies for further comment. Observers will watch whether Thinking Machines fills the technical gap, how quickly Chintala assumes CTO duties, and whether any additional staff movement follows.