xAI Cofounder Tony Wu Resigns, Fifth Founding Exit

Yuhuai Tony Wu, a cofounder of Elon Musk's artificial intelligence startup xAI, announced his resignation late Monday night in a post on the social media platform X, marking the fifth departure from the company's original 12-person founding team.

Wu, who previously worked at Google and interned at OpenAI, expressed gratitude for his time at xAI. "This company and the family we became will stay with me forever. I will deeply miss the people, the warrooms, and all those battles we have fought together," he wrote. "It's time for my next chapter. It is an era with full possibilities a small team armed with AIs can move mountains and redefine what's possible." He also thanked Musk personally for "believing in the mission and for the ride of a lifetime."

The departures have accelerated in recent months. Infrastructure lead Kyle Kosic left for OpenAI in mid-2024. Google veteran Christian Szegedy departed in February 2025. In August, Igor Babushkin exited to establish an AI safety-focused venture capital firm. Last month, Greg Yang stepped back from his role to address health complications from chronic Lyme disease. All accounts describe the separations as amicable, though they come...