Thinking Machines co-founder Lilian Weng left the company citing health reasons, then joined OpenAI

In Brief Posted: 2:07 PM PDT · July 29, 2026 Image Credits:Samuel Boivin/NurPhoto / Getty Images Amanda Silberling Thinking Machines co-founder Lilian Weng left the company citing health reasons, then joined OpenAI Lilian Weng, co-founder of Thinking Machines, announced this week that she would…

In Brief Posted: 2:07 PM PDT · July 29, 2026 Image Credits:Samuel Boivin/NurPhoto / Getty Images Amanda Silberling Thinking Machines co-founder Lilian Weng left the company citing health reasons, then joined OpenAI Lilian Weng, co-founder of Thinking Machines, announced this week that she would step down from her role, citing health issues. “I don’t feel I’m able to continue at the pace a startup requires,” she wrote in an internal Slack message, which she also shared on X. “After thinking about it for several months, I ultimately have to admit that the amount of consistent stress and workload have pushed me beyond what my health can sustain physically.” On Wednesday, OpenAI told TechCrunch that Weng would be rejoining the company, where she previously served as the VP of AI Safety Research. According to a company spokesperson, Weng will lead a top-level team focused on accelerating OpenAI’s internal research. This team will support cross-research work on recursive self-improvement, a process that would allow an AI system to iterate on itself to become more powerful. This move could be read as contradictory to Weng’s statements about the impact of working at a fast-paced startup on her health — however, she likely won’t face as much direct pressure while working at a company where she isn’t a co-founder. Still, in a time of fierce competition for talent among AI labs, this high-profile departure is notable. Thinking Machines co-founder and former OpenAI CTO Mira Murati replied to Weng’s X post earlier this week and expressed support for her decision to focus on her health. It is unclear if Murati was aware that Weng would rejoin OpenAI. It is a hard and sad decision. I shared this message with folks at Thinky. Thank you all for the time together♥️ Just as the last sentence in my message: The future worth building is human. pic.twitter.com/VGb5fM5chX— Lilian Weng (@lilianweng) July 27, 2026 “We’ll miss you, it’s been wonderful building Thinky together. I’m glad that you’re putting your health first. Thank you for everything,” Murati wrote in response to Weng’s post. Topics AI, In Brief, OpenAI, TC, Thinking Machines October 13 – 15 San Francisco Scale faster. Grow your portfolio. Gain practical expertise. No matter your goal, Disrupt can empower you.Save up to $330 today! REGISTER NOW Newsletters See More Subscribe for the industry’s biggest tech news Related Enterprise Microsoft is openly competing with OpenAI, Anthropic more than ever Julie Bort 4 hours ago AI The Hugging Face AI break-in explained Connie Loizos 9 hours ago AI Sam Altman is ready to decelerate Tim Fernholz 1 day ago Latest in AI Enterprise Microsoft is openly competing with OpenAI, Anthropic more than ever Julie Bort 4 hours ago AI Mark Zuckerberg predicts that billions of people will have personal AI agents in five years Amanda Silberling 6 hours ago In Brief Microsoft logs $3.2B from Anthropic investment, but OpenAI was a mixed bag Julie Bort 6 hours ago

Source: TechCrunch — Published July 29, 2026 at 21:07 UTC — Category: Business