The first week of the Musk v. Altman trial concluded on Thursday, with proceedings set to resume next week.

Tesla and SpaceX CEO Musk testified over the course of three days, hammering home his argument that OpenAI’s Sam Altman and Greg Brockman were trying to “steal a charity.”

Musk sued OpenAI, Altman and Brockman in 2024, alleging they went back on their promises to keep the AI startup a nonprofit.

A week into the Musk v. Altman trial, which features two towering figures in the tech industry facing off in a case that could have major implications for OpenAI, the plaintiff has made his central message clear to the jury. 

“You can’t just steal a charity,” Elon Musk, the world’s richest person, noted repeatedly during his time on the stand at a federal courthouse in Oakland, California. 

Musk’s testimony was the centerpiece of the trial’s first week. It comes two years after the Tesla and SpaceX CEO first sued OpenAI CEO Sam Altman and Greg Brockman, the company’s president, alleging they went back on their promises to keep the artificial intelligence startup a nonprofit and to follow its charitable mission.

Musk, who helped start OpenAI in 2015 as a nonprofit, claims that the roughly $38 million he donated to the project was used for unauthorized commercial purposes. OpenAI, now valued at over $850 billion by private investors, has called Musk’s allegations “baseless.” Musk left OpenAI’s board in 2018, and five years later started xAI as a competitor, before merging that business with SpaceX in February. 

The trial began Monday with the seating of a nine-person jury. Attorneys for both parties presented opening arguments on Tuesday. The main event was Musk’s testimony, which stretched over the course of three days, wrapping up on Thursday. 

The courtroom was dark on Friday, and proceedings will resume next week, with Judge Yvonne Gonzalez Rogers, an appointee of former President Barack Obama, presiding over the case. Altman and Brockman are expected to testify later this month.

After Musk left OpenAI, the AI lab began moving more towards commercialization, creating a for-profit subsidiary in 2018. The business started booming after the launch of ChatGPT in late 2022, and the subsequent raising of $10 billion in equity from Microsoft. 

Musk testified that he is not entirely against OpenAI having a for-profit unit, but he commented it became “the tail wagging the dog.” He repeatedly accused Altman and Brockman of enriching themselves from a charity while also reaping the positive associations that come from running a nonprofit.

“What you can’t do is have your cake and eat it too,” Musk mentioned from the stand.

Musk commented he started OpenAI to serve as a “counterweight” to Google, which he viewed as having insufficient concerns surrounding AI safety. Musk remarked he got into an argument about the subject with Google co-founder Larry Page, a former friend, who called him a “speciesist for being pro-human.”

Musk noted OpenAI wouldn’t exist without him. 

“I came up with the idea, the name, recruited the key citizens, taught them everything I know, provided all the initial funding,” Musk noted.

Musk’s xAI interests

During cross-examination, Musk repeatedly clashed with OpenAI lead counsel William Savitt of Wachtell Lipton. He accused Savitt of lying and asking misleading questions that were “designed to trick” him.

Savitt asked Musk about his involvement in negotiations to establish OpenAI’s for-profit arm, as well as what he knew about the nonprofit’s recent initiatives. He also asked about his competing AI organization, xAI, which Musk passed off as being a fraction the size of OpenAI with minimal sector share, even though he valued it a $250 billion in the merger with SpaceX.

Musk revealed that it’s “partly” true that xAI used some of OpenAI’s digital systems to train its own models, a process known as distilling. He downplayed xAI’s reliance on OpenAI and noted, “It is standard practice to leverage other AIs to validate your AI.”

Musk told the jury that while he had been growing “uncomfortable” with Altman and Brockman’s behavior around 2017, he didn’t think he had a basis to sue until much later. 

“I would’ve filed a lawsuit sooner if I thought they’d stolen the charity sooner,” Musk said. 

In a January filing, Musk’s attorneys commented their client should receive up to $134 billion in damages from OpenAI and Microsoft, which is also named as a defendant. Musk’s team now says any “ill-gotten gains” should be returned to OpenAI’s foundation.

Musk is also seeking to have Altman and Brockman removed from their roles and to “unwind OpenAI’s for-profit conversion and restructuring.” 

All that’s happening while Musk and Altman are pushing their respective companies towards public offerings that could be the largest in history. SpaceX has already filed confidentially with the SEC and is reportedly expected to launch its roadshow in mid-June for an IPO that could value the firm in the trillions of dollars.

Following the end of Musk’s testimony on Thursday, his lawyers called Jared Birchall, who manages Musk’s family office, as their next witness. This also touches on aspects of investors.

Birchall testified about the specific donations Musk made to OpenAI, as well as his knowledge about Musk’s multibillion-dollar bid to acquire OpenAI last year. In February of 2025, Musk led a group of investors in offering to invest in control of OpenAI for $97.4 billion, an effort that Altman immediately rejected.

Before the proceedings kicked off on Monday, Gonzalez Rogers opted to split the trial into two parts: a liability phase to determine whether any wrongdoing occurred, and a remedies phase to decide the appropriate outcomes and next steps. Gonzalez Rogers expects the former to conclude by May 21

The jury will weigh in during the liability phase only, and its verdict will be advisory, which means Gonzalez Rogers will construct the final decision.

—CNBC’s Lora Kolodny contributed to this report.

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