The trial centres on the 2015 birth of ChatGPT maker OpenAI as a nonprofit startup primarily funded by Musk before evolving into a capitalistic venture now valued at $US852 billion.
The trial's outcome could sway the balance of power in AI - breakthrough technology that is increasingly being feared as a potential job killer and an existential threat to humanity's survival.
Those perceived risks are among the reasons that Musk, the world's richest person, cites for filing an August 2024 lawsuit that will now be decided by a jury and US District Judge Yvonne Gonzalez Rogers in Oakland, California.
The civil lawsuit accuses Altman, OpenAI's CEO, and his top lieutenant, Greg Brockman, of double-crossing Musk by straying from the San Francisco company's founding mission to be an altruistic steward of a revolutionary technology. The lawsuit alleges they shifted into a money-making mode behind his back.
Musk initially presented 26 claims in 2024, which were ultimately reduced to two.
OpenAI has brushed off Musk's allegations as an unfounded case of sour grapes that's aimed at undercutting its rapid growth and bolstering Musk's own xAI, which he launched in 2023 as a competitor.
Gonzalez Rogers questioned potential jurors about their views on Musk, Altman and artificial intelligence. Both Altman, who was present on Monday, and Musk are expected to testify.
Musk, who invested about $US38 million in OpenAI from December 2015 through May 2017, initially was seeking more than $US100 billion in damages.
But any damages now are likely to be much smaller after a series of pre-trial rulings that went against Musk. Musk has since abandoned a bid for damages for himself and instead is seeking an unspecified amount of money to be paid to fund the altruistic efforts of OpenAI's charitable arm.
Musk's lawsuit also seeks Altman's ouster from OpenAI's board. Musk's decision to stop funding the company contributed to a bitter falling out between the former allies.
Musk says he was responding to deceptive conduct that OpenAI's board picked up on when it fired Altman as CEO in 2023 before he got his job back days later.
But the trial also carries risks for Musk, who last month was held liable by another jury for defrauding investors during his $US44 billion takeover of Twitter in 2022.
Any damaging details about Musk and his business tactics could be particularly hurtful because his rocket ship maker, SpaceX, plans to go public this year in an initial public offering that could make him the world's first trillionaire.
The trial is expected to provide riveting theatre, with contrasting testimony from two of technology's most influential and polarising figures in the 54-year-old Musk and the 41-year-old Altman.
"Part of this is about whether a jury believes the people who will testify and whether they are credible," Rogers said during a court hearing earlier this year.
The judge will make the final decision on the case, with the jury serving in an advisory role.
with EFE
