Thinking Machines CTO fired for 'unethical conduct' as co-founders defect back to OpenAI
Jan 14, 2026
Key Points
- Thinking Machines fires CTO Barrett Zof for alleged unethical conduct as multiple co-founders defect back to OpenAI, undermining the $12 billion startup's core leadership.
- The company's public blame-shifting via misconduct allegations draws skepticism from researchers who view it as retaliation for an impending defection.
- Thinking Machines faces a credibility crisis: talent exodus, unproven product beyond an API fine-tuning tool, and office gym equipment that signals instability to investors.
Summary
Thinking Machines terminated CTO Barrett Zof for alleged unethical conduct, CEO Mira Murati announced to staff today. Sumath Chentala will take over as CTO. Three co-founders departed yesterday to rejoin OpenAI, with additional employees following.
Thinking Machines raised roughly $12 billion and launched with six co-founders, including John Schulman from OpenAI's reinforcement learning team. The company has shipped mostly research blog posts. Its primary product to date is Tinker, an API for fine-tuning that users regard highly. The broader strategy centers on building reinforcement learning environments for enterprise use cases, work the team is theoretically well-positioned to execute given Schulman's background.
The timing and messaging create a credibility problem. The company is bleeding talent back to OpenAI while simultaneously rolling out branded gym equipment at its office, a signal that typically reads poorly to investors and observers when paired with organizational instability. The "unethical conduct" framing has drawn skepticism on social media. Susan Jang, a researcher at DeepMind, characterized it as "character assassination" of the type companies deploy when discovering that a co-founder might defect. Rune called it "snaky PR."
Thinking Machines faced immense expectations from day one given its funding, team pedigree, and OpenAI alumni returning to build a competitor. Those expectations remain unchanged. Losing multiple co-founders back to OpenAI makes near-term delivery harder. The company retains Schulman and other top talent according to people familiar with hiring there, but the exodus suggests either internal friction, a loss of confidence in the mission, or both. Public blame-shifting via misconduct allegations may accelerate rather than arrest the departures.