Co-founder churn is continuing at the top AI labs with another major departure.
Yuhuai (Tony) Wu, a co-founder of Elon Musk’s xAI, announced his resignation today in a heartfelt post reflecting on his time at the company. “I resigned from xAI today. This company – and the family we became – will stay with me forever,” Wu wrote, adding that he would “deeply miss the people, the warrooms, and all those battles we have fought together.”
Wu’s departure marks the fifth co-founder to leave xAI since its founding, bringing the total co-founder count down to seven. The AI startup, launched with twelve co-founders , has now seen Igor Babuschkin, Kyle Kosic, Christian Szegedy and Greg Yang exit alongside Wu.
Babuschkin left in August 2025 to launch Babuschkin Ventures, a venture capital firm focused on safe AI development. Kosic departed in 2024 to join OpenAI, while Szegedy also left in 2024 for a position at Morph Labs. Greg Yang departed last month citing health issues after a Lupus diagnosis.
In his resignation announcement, Wu hinted at future plans, stating “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 thanked Musk directly, calling his time at xAI “the ride of a lifetime.”
Despite being one of the newest players in the AI race, xAI’s founder departures place it within a broader industry trend of leadership instability. OpenAI has experienced the most dramatic exodus, with eight of its eleven original co-founders having left the company. Departed founders include Elon Musk himself, Ilya Sutskever (who went on to found Safe Superintelligence Inc.), John Schulman (now at Thinking Machines), and Durk Kingma (now at Anthropic).
Thinking Machines, co-founded by former OpenAI CEO Mira Murati, has lost three of its six co-founders—Barrett Zoph, Andrew Tulloch, and Luke Metz. Safe Superintelligence Inc. has seen one of its three co-founders, Daniel Gross, depart for Meta in 2025. Even the more established Google DeepMind experienced founder attrition when Mustafa Suleyman left to lead AI initiatives at Microsoft.
Against this backdrop of widespread departures, Anthropic stands as the sole major AI laboratory to retain its entire founding team. All seven co-founders who established the company in 2021—including CEO Dario Amodei and President Daniela Amodei—continue to work at the organization, a rarity in an industry marked by volatility and competitive poaching.
As the race to develop advanced AI systems intensifies, the significance of founder stability remains an open question. Wu’s departure from xAI adds another data point to an industry-wide pattern that shows even the most ambitious AI ventures struggle to keep their founding teams intact.