OAKLAND, California: A courtroom battle between Elon Musk and Sam Altman is set to put one of Silicon Valley's most influential partnerships under the spotlight, as a jury weighs claims of betrayal and competing visions for the future of artificial intelligence.

The trial that began on April 27, with its jury selection, focuses on the origins of OpenAI, which was founded in 2015 as a nonprofit backed in part by Musk before evolving into a for-profit powerhouse now valued at US$852 billion.

At its core, the case examines whether OpenAI's leadership abandoned its founding mission to develop AI for the broader good and instead shifted toward a commercial model. Musk, who filed the lawsuit in August 2024, argues that the change represents a breach of trust and a departure from the organization's original goals.

The civil complaint accuses Altman and co-founder Greg Brockman of double-crossing Musk by steering the company into a profit-driven direction without his consent. OpenAI has rejected the claims, describing them as an attempt to slow its growth while boosting Musk's rival venture, xAI.

The stakes extend beyond the individuals involved. The outcome could influence the balance of power in the rapidly evolving AI industry, which is increasingly seen as both transformative and potentially disruptive to jobs and society.

Musk, who invested about $38 million in OpenAI between 2015 and 2017, had initially sought more than $100 billion in damages. However, after a series of pre-trial rulings, he is no longer pursuing personal compensation and instead is seeking funds to support OpenAI's nonprofit arm. Any payments would likely come from the company's for-profit operations and its largest backer, Microsoft.

The lawsuit also calls for Altman's removal from OpenAI's board. The dispute traces back to Musk's decision to stop funding the company, which contributed to a falling-out between the former collaborators. Musk maintains that OpenAI's leadership engaged in deceptive conduct, citing the board's brief 2023 decision to remove Altman as CEO, only to reinstate him days later.

"Part of this is about whether a jury believes the people who will testify and whether they are credible," said Yvonne Gonzalez Rogers during a hearing earlier this year. The jury will play an advisory role, with the judge making the final ruling.

The trial is also expected to delve into the early days of the AI race, including the relationship between Musk and Altman, which began with a shared goal of developing AI more responsibly than rivals such as companies linked to Larry Page, Sergey Brin, and Mark Zuckerberg.

Evidence includes a February 2023 email exchange between the two men. After letting Musk know "you're my hero," Altman tells him: "I am tremendously thankful for everything you've done to help —I don't think OpenAI would have happened without you — and it really (expletive) hurts when you publicly attack OpenAI."

Musk's response: "I hear you, and it is certainly not my intention to be hurtful, for which I apologize, but the fate of civilization is at stake."

Beyond the legal arguments, the trial promises a rare look at the personalities and pressures shaping the global AI race, with testimony from two of its most prominent and polarizing figures.