Elon Musk’s xAI has seen its second co-founder, Jimmy Ba, leave just two days after the first, Tony Wu left.

On Tuesday, influential researcher Ba announced his departure on X, expressing gratitude to Musk and saying he was “grateful to have helped cofound at the start.”

Ba’s exit follows that of fellow co-founder Wu, who left xAI just a day earlier.

The departures come shortly after xAI merged with Musk’s SpaceX, which is preparing for a public offering later this year.

The University of Toronto professor was credited with key research behind xAI’s Grok version 4 AI models.

Alongside Ba and Wu, other co-founders—including Igor Babuschkin, Kyle Kosic, and Christian Szegedy—have also departed Musk’s AI venture.

Last month, Greg Yang announced he would step back from his role to focus on managing Lyme disease.

The exits coincide with xAI coming under regulatory scrutiny across Europe, Asia, and the U.S.

The investigations were launched after the company’s Grok AI chatbot and image generator facilitated the widespread creation and sharing of non-consensual explicit content, often called deepfake pornography.