Musk, the world's richest man, was a co-founder of OpenAI, which launched in 2015 and went on to create ChatGPT. After investing $38 million in its first years, Musk accused OpenAI CEO Sam Altman and his top deputy of shifting into a moneymaking mode behind his back.
The nine-person jury found that Musk waited too long to file his lawsuit and missed the deadline for the statute of limitations. The jury had deliberated only two hours.
The jury served in an advisory role, but Judge Yvonne Gonzalez Rogers accepted the verdict Monday as the court's own and dismissed Musk's claims.
The three-week trial in Oakland, California shed light on the bitter falling-out between the two Silicon Valley titans and the beginnings of OpenAI, now a company valued at $852 billion and moving toward potentially one of the largest initial public offerings in history.
Altman and OpenAI claimed there was never a promise to keep OpenAI a nonprofit forever. In fact, they argued, Musk knew this and filed his lawsuit because he couldn't have unilateral control over the fast-growing AI developer.
WATCH: OpenAI attorney speaks after jury sides with company in feud with Elon Musk
OpenAI attorney speaks after jury sides with company in feud with Elon Musk
Musk was seeking damages to be paid to the altruistic efforts of OpenAI's charitable arm as well as Altman's ouster from OpenAI's board. Musk's decision to stop funding the company contributed to a bitter rift 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.
Musk did not immediately respond to a request for comment.
The three-week trial saw testimony from Musk, Altman and his top lieutenant Greg Brockman, along with Microsoft CEO Satya Nadella and a slew of others in the tech titans' orbit. Musk told jurors on his first of three days on the stand that, fundamentally, "I think they're going to try to make this lawsuit ... very complicated, but it's actually very simple," Musk said. "Which is that it's not OK to steal a charity."
Musk's lawsuit claimed that, in addition to "breach of charitable trust," Altman and Brockman unjustly enriched themselves from the windfall as the ChatGPT maker soared in valuation. Brockman revealed during the trial that his stake in OpenAI is worth about $30 billion.
OpenAI has brushed off Musk's allegations as an unfounded case of sour grapes aimed at undercutting its rapid growth and bolstering Musk's own xAI, which he launched in 2023 as a competitor. During cross-examination, Musk was sometimes combative with OpenAI lawyer William Savitt.
"Your questions are not simple," Musk said at one point. "They are designed to trick me essentially."
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Jurors also heard from witnesses including OpenAI ex-board members Helen Toner and Tasha McCauley, who spoke about the decision to fire Altman in 2023. They were ousted from the board themselves when Altman returned to his role a few days later.
Altman and Musk both vied to be OpenAI's CEO in its early years. In his testimony, Altman said he had concerns about Musk's attempts to gain more control over OpenAI, which was aiming to safely build a better-than-human form of AI called artificial general intelligence.
"Part of the reason we started OpenAI is we didn't think AGI could be under the control of any one person, no matter how good their intents are," Altman said.
Near the end of his testimony, Altman said that before things turned sour, he had thought very highly of Musk.
"I felt like he had abandoned us, not come through on his promises, put the company in a very difficult place, jeopardized the mission, didn't really care about the things I thought he cared about," Altman said. "It's been an extremely painful thing for me ... to have someone that I respected so much not acknowledge that and continue to publicly attack us."