OpenAI boss Sam Altman has insisted he is an "honest and trustworthy businessperson", as he rejected Elon Musk's claim he moved to "steal" the company and turn it from a charity into a capitalist venture.
The two tech titans are at the centre of a California court battle over the firm behind ChatGPT.
Mr Musk, who gave evidence last month, has accused Mr Altman, OpenAI and its president, Greg Brockman, of wooing millions of dollars from him between 2015 and 2017, when it was a non-profit, and then in 2019 moving to transform it into a corporate entity to enrich themselves.
The launch of ChatGPT in 2022 transformed the company into one of the most powerful tech firms, and Mr Musk has suggested that the "not trustworthy" Mr Altman being in charge is "a very big danger for the whole world".
Read more: The Altman vs Musk battle explained
Under questioning in court on Tuesday, Mr Altman refuted the Tesla mogul's bid to paint him as unreliable.
"I believe I am an honest and trustworthy businessperson," he said.
Pressed on whether he had "misled people" while doing business, he replied: "I do not think so."
Mr Altman also denied the accusation that he had tried to "steal a charity" with his leadership of OpenAI, which is preparing for a possible initial public offering that could value it at $1trn (£739bn).
He said Mr Musk had not opposed the plan to create a for-profit arm of the firm in 2019, claiming the SpaceX boss knew about the plan before he quit the board the year before.
He claimed Mr Musk once demanded a 90% stake in OpenAI, which made him feel "extremely uncomfortable".
"I don't think Mr Musk understood how to run a good research lab," he added.
"He had demotivated some of our most key researchers."
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Testimony in the trial could conclude later this week, and jurors could begin deliberating whether the defendants are liable within days.
Mr Musk, the world's richest person, wants $150bn (£111bn) in damages from OpenAI and investor Microsoft, to be paid into a non-profit, and wants Mr Altman and Mr Brockman removed from their roles.
OpenAI claims he is only suing because he regrets leaving the board and missing out on potential riches.
(c) Sky News 2026: OpenAI trial: Sam Altman insists he's trustworthy in riposte to Elon Musk
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