Who is Jimmy Ba? xAI co-founder quits Elon Musk’s AI startup, thanks team and hints at what’s next

Jimmy Ba, one of the co-founders of Elon Musk’s AI startup xAI, says he’s stepping away. He shared the news on X, looking back at his time there and thanking Musk for pulling the early crew together. He also took a moment to thank his teammates. For Ba, the people mattered more than anything the company shipped.


In his goodbye post, he made it pretty clear that xAI was never just about code or big ideas. It was the late nights. The back-and-forth. The small wins that only the team would notice. And even though he’s leaving, he says he’s not disappearing. He’ll stay in touch and keep rooting for them from the outside.


So what’s next? Ba hinted that tech is moving at a crazy pace right now. The tools are getting better fast, and that’s going to change how people work. He thinks the year ahead could be a heavy one for AI. Busy. Messy. And kind of a big deal for where all this is headed.


But the timing is what caught people’s attention. His exit comes just two days after another xAI co-founder, Tony Wu, said he was also leaving. Two founders, back to back. That set off a lot of chatter online, with people wondering what’s going on inside Musk’s AI shop.

Who is Jimmy Ba?

Ba is a Canadian machine learning researcher and a professor at the University of Toronto. He did his PhD there in 2018 with Geoffrey Hinton, one of the big names in the field. In 2023, he teamed up with Musk and a small group of researchers to help start xAI, which is building advanced AI systems.

How did people react online?

The replies rolled in fast. Some folks were curious. Why are so many founders leaving so close together? Others were more personal. Teammates and people who’d worked with Ba thanked him, called him a steady presence, and wished him well for whatever comes next.

How many xAI co-founders have left?

With Ba gone, six out of the 12 original co-founders have now moved on. Over the past couple of years, a few key names have exited for different reasons. Kyle Kosic left in 2024 to join OpenAI. Christian Szegedy wrapped up his stint in 2025. Igor Babuschkin left to start a venture firm. Greg Yang stepped away in January 2026 because of health issues. And earlier this week, Tony Wu said he was starting a new chapter. Then Ba followed.


And yes, that’s a lot of change for a young company.


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