OpenAI’s lawyers argue Musk’s lawsuit aims to undermine the company for his competing venture, xAI.

Tech billionaire Elon Musk has taken the stand for a second day in a landmark United States trial against Sam Altman, a fellow OpenAI co-founder whom he accuses of betraying promises to keep the company a nonprofit dedicated to humanity’s benefit.

The trial centres on OpenAI’s 2015 founding as a nonprofit that later evolved into a for-profit venture.

In the company’s early years, Musk invested about $38m between 2015 and 2017. The world’s richest man, Musk gave testimony in the case on Wednesday, telling jurors that he lost confidence that Altman would maintain the company’s nonprofit mission.

Musk, who left the company in 2018, said that by late 2022, he was concerned that Altman was trying to “steal the charity” and alleged that “it turned out to be true”.

Altman was present at the proceedings in a California federal court, but did not testify.

OpenAI’s lawyers pushed back on Musk’s claims. The artificial intelligence (AI) giant’s legal team said that there was never a commitment to remain a nonprofit.

OpenAI’s attorneys alleged that Musk’s lawsuit is an attempt to undermine the AI giant in favour of his own venture, xAI. This comes as OpenAI is poised for an initial public offering (IPO) that could value it at $1 trillion, according to Reuters.

OpenAI said it had created a for-profit arm of the company as part of efforts to fund its computing power ambitions and attract talent.

Musk pushed back on the remarks and claimed that the company had been “captured,” and described an offer from Altman to let him invest as feeling “like a bribe”.

Musk is seeking $150bn in damages from OpenAI and Microsoft, with any award directed to OpenAI’s charitable arm. He is also asking the court to force OpenAI to return to nonprofit status and remove Altman and co-founder Greg Brockman from leadership.

OpenAI, now structured as a public benefit corporation, says Musk’s claims are driven by competition, noting his AI company xAI trails OpenAI in user adoption.