xAI's Founding Team Shrinks as Another Co-Founder Steps Down
Another Founding Member Departs Elon Musk's AI Venture

The revolving door at Elon Musk's artificial intelligence company xAI continues to spin. Toby Pohlen, one of the original architects behind the ambitious AI startup, announced his resignation this week - becoming the seventh co-founder to depart since the company launched in mid-2023.
Pohlen broke the news himself on X (formerly Twitter), offering a surprisingly personal glimpse into life at Musk's notoriously demanding AI lab. "Three years, thousands of PRs (pull requests), and more sleepless nights than I can count," he wrote affectionately about his former colleagues. "Nobody outlasts you all pulling all-nighters." His first post-departure plan? "A full eight hours of sleep - then we'll see what comes next."
The Shrinking Core Team
When xAI debuted with much fanfare in July 2023, it boasted an all-star roster of twelve technical founders handpicked from top AI labs and academia. Today, that number has dwindled to just five remaining original members.
The exodus began quietly in 2024 when infrastructure head Kyle Kosic left for OpenAI. Since then, departures have accelerated:
- Jimi Ba (February 2026): University of Toronto professor who spearheaded Grok4 development
- Yu Huai Wu (February 2026): Ex-Google scientist focused on reasoning systems
- Yangge (January 2026): Stepped back citing Lyme disease complications
- Igor Babuschkin (August 2025): Pivoted to AI safety investing
- Christian Szegedy (February 2025): Former Google senior researcher
Pohlen had been leading Macrohard, xAI's experimental digital agent project. His departure leaves questions about that initiative's future direction.
What This Means for xAI
The steady attrition raises eyebrows in Silicon Valley circles where retaining top technical talent often makes or breaks AI startups. While some turnover is expected in fast-moving fields, losing over half your founding team in under three years suggests deeper challenges.
Industry analysts speculate whether these exits reflect:
- The grueling pace typical of Musk-led companies
- Strategic disagreements about technical direction
- Competitive poaching from better-funded rivals
The remaining founders now face increased pressure to deliver on xAI's ambitious mission - developing what Musk describes as "maximally curious" AI that seeks fundamental truths about the universe.
Key Points:
- Toby Pohlen becomes seventh xAI co-founder to depart since 2023 launch
- Only five original members remain from initial twelve-person founding team
- Departures span research leads and project managers across multiple initiatives
- Comes amid intense competition for elite AI talent industry-wide

