xAI co-founder Jimmy Ba said Tuesday that he has left Elon Musk’s AI startup.
In a post on X, Ba wrote that it was time to “recalibrate” and said 2026 would be an important year for the future. Ba had reported directly to Musk and once managed large parts of the company. Over the past year, some of his duties were reassigned to other co-founders, including Tony Wu and Guodong Zhang. He also previously led a team of more than 1,000 AI tutors.
Ba is the second co-founder to leave in less than 48 hours. Tony Wu resigned Monday night, and some of his responsibilities were also shifted to Zhang. Musk launched xAI in 2023 with 11 other founders. Six have now left, most within the past year.
Ba is also an assistant professor of computer science at the University of Toronto, where he earned his Ph.D. under AI pioneer Geoffrey Hinton.
xAI has faced controversy in the past year, including criticism over its Grok chatbot generating offensive content and non-consensual images. The company later limited some of Grok’s features. Musk recently announced plans to merge xAI with SpaceX, which is reportedly preparing for a major public offering.
