Manuel Kroiss has told people he is leaving artificial intelligence company xAI, according to people with knowledge of his exit. With Kroiss's departure, ten of the eleven engineers who helped launch xAI alongside Elon Musk in 2023 have now left the company.

Kroiss led pretraining at xAI, which helps train the company's AI models on large datasets. He reported directly to Musk and worked on improving xAI's coding models alongside Guodong Zhang, who left the company in March 2026.

Guodong Zhang, Zihang Dai, Toby Pohlen, Jimmy Ba, Tony Wu, and Greg Yang have stepped away from xAI since January. Ross Nordeen is the only remaining xAI cofounder besides Musk.

The departures have occurred as xAI's organizational structure has been in flux over the past few weeks, according to people with knowledge of the changes. Musk has taken over managing dozens of direct reports and has brought in employees from Tesla and SpaceX.

"xAI was not built right first time around, so is being rebuilt from the foundations up," Musk wrote on X. He also posted that "Many talented people over the past few years were declined an offer or even an interview @xAI."

xAI has shed dozens of employees in recent weeks, according to people with knowledge of the changes. Musk said at the Abundance Summit that xAI was behind in coding and working to exceed its competitors on coding.

Kroiss, also known by the nickname "Makro," previously worked at Google and DeepMind before joining xAI. Nordeen joined xAI from Tesla.

SpaceX acquired xAI in early 2026. The company is expected to file an initial public offering in 2026 that could value it at $1.5 trillion.