Two co-founders of Elon Musk’s artificial intelligence start-up xAI have resigned this week, reducing the company’s original founding team by half less than three years after its launch.

Reuters reported on Monday that Tony Wu and Jimmy Ba confirmed their departures in separate posts on X, without giving detailed reasons for leaving. Their exits leave six of the 12 original co-founders still at the company, marking the latest in a series of senior departures.

Wu wrote: “It’s time for my next chapter. It is an era with full possibilities: a small team armed with AIs can move mountains and redefine what’s possible.” Ba said in a separate post that it was his final day at xAI, adding: “It’s time to recalibrate my gradient on the big picture.”

Bloomberg News reported that Wu announced his exit on Monday and Ba followed a day later, becoming the fifth and sixth founding members to leave in the past two years. Kyle Kosic departed in 2024, followed by Igor Babuschkin and Christian Szegedy last year. Greg Yang, another co-founder, said last month that he would step back after being diagnosed with Lyme disease.

The Financial Times reported that Ba’s resignation followed tensions within xAI’s technical team over pressure to improve model performance as Musk seeks to close the gap with rivals such as OpenAI and Anthropic. Ba did not respond to a request for comment on that report, according to the FT.

The departures come days after SpaceX said it would acquire xAI in a deal valuing the combined company at $1.25 trillion, according to Bloomberg News. The transaction values SpaceX at $1 trillion and xAI at $250 billion, based on documents seen by CNBC.

Wu previously worked at Alphabet’s Google, and both he and Ba studied at the University of Toronto, according to Bloomberg News. Neither outlined their next roles in their public statements.

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