Elon Musk takes stand in trial vs. Sam Altman that could reshape AI's future

Elon Musk arrives at the U.S. District Court in Oakland, Calif., Tuesday, April 28, 2026.

OAKLAND, Calif. — Elon Musk, the Tesla CEO, world’s richest man and OpenAI cofounder, took the stand Tuesday in a high-stakes trial revolving around a bitter feud between himself and former friends Sam Altman and Greg Brockman that could reshape the future development of artificial intelligence.

The bickering billionaires’ appearances at the Oakland, California, federal courthouse foreshadow the start of a legal drama that is expected to brim with intrigue and potentially embarrassing details about the two tech moguls. Musk filed the lawsuit against Altman and Brockman along with Microsoft over its investments in OpenAI, in 2024.

“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.”

The jury was elected Monday and the trial is scheduled to take three weeks.

Opening arguments began with Musk’s attorney, Steven Molo, who quoted OpenAI’s mission statement when it was created as a nonprofit for the benefit of humanity as a whole and not constrained by the need to generate financial enrichment for anyone.

Altman and his top lieutenant Brockman, aided by Microsoft, “stole a charity,” Molo said, “a charity whose mission was the safe, open development of artificial intelligence.”

In the civil lawsuit, Musk accuses Altman and Brockman of double-crossing him by straying from the San Francisco company’s founding mission to be a steward of a revolutionary technology. He is seeking damages and to fund the altruistic efforts of OpenAI’s charitable arm and Altman’s ouster from OpenAI’s board.

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.

In his opening statement, OpenAI lawyer William Savitt told jurors “we are here because Mr. Musk didn’t get his way with OpenAI.”

Savitt said Musk used his promises to provide funding to bully OpenAI founding members and tried to take control of OpenAI and merge it with Tesla. In fact, he said Musk wanted to form a for-profit company and own more than 50% of it. In the middle of discussions about OpenAI’s future, he added, Musk pulled the plug on $5 million quarterly donations he was making.

There is no record, Savitt said, of promises made to Musk that OpenAI was going to remain a nonprofit forever, or open-source everything. What Musk ultimately cared about, he said, was not OpenAI’s nonprofit status but winning the AI race with Google.

Molo said the case is not about Musk, but rather Altman, Brockman and Microsoft.

By 2017, about two years after OpenAI’s founding, it became clear that OpenAI would need more money, and Molo said the founders eventually settled on the idea of creating a for-profit arm of OpenAI that would support the nonprofit. Terms were capped for investors so they “couldn’t make infinite profit.”

“There is nothing wrong with a nonprofit having a for-profit subsidiary, but (it) has to advance the mission,” Molo said.

Microsoft initially invested $2 billion in OpenAI. Then, in 2022, news spread that OpenAI had done a deal with Microsoft and “this was a horse of a completely different color,” he said. It was a “gamechanger,” Molo said, that violated “every commitment” OpenAI made not just to Musk but to the world. It was no longer open source, it became a for-profit company for the benefit of the defendants and Microsoft was going to have control, through licensing, of much of its intellectual property, Molo said.

After opening arguments wrap up, testimony will begin with Musk’s side presenting a tale chock full of alleged betrayal, deceit and ambition that caused OpenAI to pivot from its founding mission as an altruistic startup to a capitalistic venture now valued at $852 billion.

Musk, the world’s richest person with an estimated fortune of $778 billion, is among the witnesses who will testify during the trial.

Altman, OpenAI’s CEO, is also expected to testify, along with Microsoft CEO Satya Nadella, one of the technology leaders who helped fund the late 2022 release of ChatGPT, the chatbot that unleashed the current AI boom that has propelled the stock market to record heights.

Altman’s court appearance likely made him unavailable to attend an Amazon event across San Francisco Bay on Tuesday at which both companies announced an expanded partnership.

“I wish I could be there with you in person today,” Altman told attendees of Amazon’s event in San Francisco via a prerecorded video message. “My schedule got taken away from me today.”

AP Technology Writer Matt O’Brien contributed to this story from Providence, Rhode Island.

Barbara Ortutay, The Associated Press