Musk’s testimony dominated the first week of the Musk v. Altman in Oakland

A week into the Musk v. Altman, which includes two high-profile figures in the technology industry facing a case that could have a major impact on OpenAI, the plaintiff made his central message clear in front of the judge.

“You can’t just steal from charity,” Elon Musk, the world’s richest man, said repeatedly during his arraignment in federal court in Oakland, California.

Musk’s testimony is central to the first week of the trial. It comes after two years Tesla and the CEO of SpaceX initially sued OpenAI CEO Sam Altman and Greg Brockman, the company’s president, saying they were going back on their promises to keep the artificial intelligence startup non-profit and follow its philanthropic mission.

Musk, who helped launch OpenAI in 2015 as a non-profit organization, says that the roughly $38 million he donated to the project was used for unauthorized commercial purposes. OpenAI, now valued at more than $850 billion by private investors, 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 on Monday where nine judges were seated. Attorneys for both sides presented opening arguments Tuesday. The main event was Musk’s testimony, which lasted three days, wrapped up on Thursday.

The courtroom was dark on Friday, and the trial will resume next week, as Judge Yvonne Gonzalez Rogers, who was appointed by former President Barack Obama, is presiding over the case. Altman and Brockman are expected to testify later this month.

After Musk left OpenAI, the AI ​​lab began to move toward sales, forming a for-profit subsidiary in 2018. The business started to grow after the launch of ChatGPT in late 2022, and the subsequent raising of 10 billion dollars Microsoft.

Musk testified that he was not completely opposed to OpenAI having a for-profit unit, but said it was “the tail wagging the dog.” He has repeatedly accused Altman and Brockman of enriching themselves through charity while favoring the good organizations that come from running a nonprofit.

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

Musk said he started OpenAI to act as a “counterweight” to him Googlehe considers there to be insufficient concern surrounding AI security. Musk said he clashed over the issue with Google co-founder Larry Page, a former friend of his, who called him “an expert on being human.”

Musk said OpenAI wouldn’t exist without him.

“I came up with the idea, the name, I hired important people, I taught them everything I know, I provided all the initial capital,” said Musk.

During his cross-examination, Musk clashed several times with OpenAI’s lead attorney William Savitt of Wachtell Lipton. He accused Savitt of lying and asking misleading questions “designed to deceive him”.

Savitt asked Musk about his involvement in discussions to establish OpenAI’s for-profit division, and what he knows about the nonprofit’s latest plans. He also asked about his competing AI company, xAI, which Musk passed off as a fraction of the size of OpenAI with a small market share, even though it cost $250 billion in a merger with SpaceX.

Musk pointed out that it is “partially” true that xAI used some OpenAI technology to train its models, a process known as distilling. He downplayed xAI’s reliance on OpenAI and said, “It’s common practice to use other AIs to validate your AI.”

Musk told the judge that while he grew “uncomfortable” with Altman and Brockman’s behavior around 2017, he didn’t think he had grounds to sue until later.

“I would quickly file a case in court if I thought they would quickly steal from charities,” said Musk.

In a January filing, Musk’s lawyers said 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 the OpenAI foundation.

Musk also wants Altman and Brockman to be removed from their roles and to “free up the transformation and restructuring of OpenAI that makes it profitable.”

All that’s happening while Musk and Altman are pushing their companies toward what could be the largest public offering in history. SpaceX has already filed confidentially with the SEC and is reportedly expected to launch its roadshow in mid-June with an IPO that could value the company in the billions of dollars.

After Musk’s testimony ended on Thursday, his lawyers called Jared Birchall, who runs Musk’s family office, as their next witness.

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

Before the trial began Monday, Gonzalez Rogers chose to divide the trial into two parts: a liability phase to determine whether wrongdoing occurred, and a remedial phase to determine appropriate consequences and next steps. Gonzalez Rogers expects the first one to end on May 21

The judge will weigh in on the credit phase only, and his decision will be advisory, meaning Gonzalez Rogers will make the final decision.

—CNBC’s Lora Kolodny contributed to this report.

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