The world's richest person alleges OpenAI, its co-founder and CEO Sam Altman and its president Greg Brockman wooed his $US38 million ($A53 million) in donations and personal help by promising to build a nonprofit that would prioritise safe development of AI, before pivoting to create a for-profit entity to enrich themselves.
William Savitt - a lawyer for OpenAI, Altman and Brockman - pressed Musk on whether he had read a term sheet that Altman forwarded on August 31, 2017, relating to OpenAI's shift from a nonprofit to a for-profit overseen by a nonprofit.
"My testimony is I didn't read the fine print, just the headline," said Musk, wearing a dark suit, dark solid tie and white shirt.
OpenAI has said Musk, the CEO of Tesla and SpaceX, is driven by a compulsion to control OpenAI and is bitter about the company's success after he left its board in 2018. They have also said he did not prioritise safety issues while with the company, and that he is trying to bolster his own AI company, SpaceX unit xAI, which lags OpenAI in user adoption.
OpenAI spearheaded widespread use of AI with its ChatGPT chatbot and has been raising billions of dollars from investors to build out its computing power ahead of a potential trillion-dollar IPO. Musk is seeking fundamental changes to the governance of the company as well as $150 billion in damages.
At times, Musk expressed frustration with Savitt's cross-examination.
"Few answers are going to be complete, especially when you cut me off all the time," Musk said.
US District Judge Yvonne Gonzalez Rogers later admonished Savitt for not letting Musk answer a question, but rejected Musk's complaints that the lawyer was leading the questioning.
Musk was asked why he did not sue OpenAI earlier, as well as how and why he did not realise it was going to become a for-profit entity. Savitt repeatedly pointed to emails sent to Musk from other OpenAI founders that show them discussing making OpenAI's technology closed-source at some point or making money from it.
"I was reassured by Sam Altman and others that OpenAI would continue as a nonprofit," Musk said.
Under questioning, Musk also said his company xAI used OpenAI to train its own models, adding: "It is standard practice to use other AIs to validate your AI."
Altman and Brockman were in the courtroom for much of Musk's testimony, watching intently. Musk was dismissed after more than two hours of questioning, followed by his top aide Jared Birchall taking the stand.
OpenAI, founded in 2015, has evolved from a nonprofit research lab in Brockman's apartment to a company worth more than $US850 billion that is planning a potential initial public offering.
Musk is seeking the $US150 billion in damages from OpenAI and Microsoft, one of its largest investors, with proceeds going to OpenAI's charitable arm. Musk also wants OpenAI to revert to being a nonprofit, with Altman and Brockman removed as officers and Altman removed from its board. Musk's claims include breach of charitable trust and unjust enrichment.
The trial started on Monday and is expected to last several weeks.
