Elon Musk’s xAI has lost its second co-founder in two days.

Influential researcher Jimmy Ba on Tuesday announced his departure in a post on X, thanking Musk and writing that he was, “Grateful to have helped cofound at the start.”

Ba’s departure comes just one day after fellow co-founder Tony Wu announced his own exit from xAI, which merged with Musk’s aerospace company SpaceX earlier this month. The xAI co-founder exodus comes as SpaceX prepares to go public sometime this year.

A University of Toronto professor, Ba was credited for critical research that influenced the company’s Grok version 4 AI models. Besides Ba and Wu, other co-founders including Igor Babuschkin, Kyle Kosic and Christian Szegedy, have also departed Musk’s artificial intelligence venture. Greg Yang announced last month that he would be stepping back from his role to focus on his battle with Lyme disease.

The record-setting, all-stock deal valued SpaceX at $1 trillion and xAI at $250 billion, according to documents viewed by CNBC. Musk previously used xAI to acquire his social network X, formerly Twitter, in another all-stock transaction announced in March 2025.

The departures also come as xAI faces regulatory probes in multiple jurisdictions across Europe, Asia and the U.S.

The probes were initiated after the company’s Grok AI chatbot and image generator allowed mass-creation and syndication of non-consensual, explicit images, colloquially known as deepfake porn. The images were based on photos of real people, including children.

Musk launched xAI in 2023 alongside 11 other people in an effort to compete against OpenAI and Google. The company’s stated goal was to “understand the true nature of the universe,” according to its website at the time.  

The company did not immediately respond to a request for comment.

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