Elon Musk's AI company xAI has once again seen significant personnel changes. Co-founder Toby Pohlen officially announced his departure. Pohlen expressed on the social platform X that during his three years at xAI, he experienced thousands of PRs (pull requests) and countless moments of laughter, and he praised the team's intense work: "No one is more capable of staying up late than you." The first thing he plans to do after leaving is to have a long sleep of more than eight hours, then think about the future.

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Pohlen's departure marks further fragmentation of xAI's founding team. Within less than three years, seven out of the original 12 co-founders have left successively, and the current retention rate is less than half.

xAI Co-founder Departure List:

  • Toby Pohlen (February 2026): The latest departee, previously in charge of the digital agent project Macrohard.

  • Jimi Ba (February 2026): Professor from the University of Toronto, who led the development of the Grok4 model.

  • Yu Huai Wu (February 2026): Former Google scientist, responsible for reasoning-related research.

  • Yangge (January 2026): Stepped back from operations due to health reasons (Lyme disease).

  • Igor Babuschkin (August 2025): Entered the AI safety venture capital field after leaving.

  • Christian Szegedy (February 2025): Former senior scientist at Google.

  • Kyle Kosic (2024): Head of infrastructure, the first co-founder to leave, now joined the competitor OpenAI.