By Angel Au-Yeung

Elon Musk is suing OpenAI in federal court, alleging that the AI giant manipulated him into thinking he was contributing tens of millions of dollars to help launch a nonprofit.

Musk, currently the richest man in the world, is seeking between $79 billion to $134 billion in damages from OpenAI and Microsoft. A judge ruled this month that the case will go to trial. It is expected to start in April in Oakland, Calif.

Documents in the case have recently been unsealed, detailing the tangled web of relationships between Musk, OpenAI leaders and Microsoft. Here's what to know.

What's the trial about?

OpenAI was founded in 2015 by a group of individuals including Chief Executive Sam Altman and President Greg Brockman. Musk donated approximately $38 million to OpenAI in its early years to help the founders pursue its nonprofit mission "to benefit humanity," according to court filings.

Musk was the primary funder for the AI company's beginnings, but he and Altman soon had a power struggle over control of the venture. In 2018, Musk stepped down from the board and stopped giving money to OpenAI in 2020, the lawsuit said.

OpenAI has since exploded in growth. The company is now raising as much as $100 billion in a fundraising round that could value the giant at as much as $830 billion. Musk's early donations to OpenAI are central to his demands for up to $134 billion in damages.

Musk also accuses Microsoft of having "knowingly aided and abetted" OpenAI, while benefiting from Musk's early donations. Microsoft became an investor in OpenAI in 2019 and has contributed billions to the company. After OpenAI's conversion to a more traditional corporate structure last fall, Microsoft's 27% stake was reported to be worth $130 billion.

Lawyers for Microsoft have denied Musk's allegations in court filings.

What's come out about it recently?

In January, more than 100 documents were unsealed as part of the continuing legal battle. The documents include texts and emails between Musk and Altman; transcripts of depositions from Musk, Altman and Microsoft CEO Satya Nadella; and even private diary entries from Brockman.

The cache of documents offer a rare glimpse into the inner sanctum of the Silicon Valley elite, revealing how deals are made and even how they regard one another.

In one instance in 2016, Musk told Altman he should try to pursue a cloud computing deal with Microsoft rather than Amazon, in part because he prefers Nadella over Amazon's then CEO, Jeff Bezos. "I think Jeff is a bit of a tool and Satya is not, so I slightly prefer Microsoft," wrote Musk to Altman in an email.

During a recorded deposition in September, Musk was asked about that same email by attorneys. "Well, I didn't call Jeff, because, you know, he's a bit of a -- I'm not sure he's (sic) likes me to be favorable because he's got a rocket company that competes with mine," said Musk according to the transcript.

"And I think the word you used at the time was Jeff was a tool," said the attorney.

"He can be, you know...There's a redemption arc for all of us," replied Musk.

What does OpenAI say?

The company issued a public blog post in mid-January titled, "The truth Elon left out." In the post, OpenAI said its founders and Musk had actually agreed in 2017 that a for-profit structure would be the next phase for the company. But those talks fell apart after the founders refused Musk's request for full control of the venture.

The company also accused Musk of cherry-picking snippets from Brockman's journal entries. A fuller version of his diary entry appeared in the blog post, showing that while the founding team did have a preference for a for-profit company, they were still open to pursuing OpenAI's mission within the nonprofit structure if it could raise enough capital.

"Elon's latest variant of his lawsuit is his fourth attempt at these particular claims, and part of a broader strategy of harassment aimed at slowing us down and advantaging his own AI company, xAI," the company wrote in the blog post.

Musk founded xAI in 2023 to try to create a true rival to OpenAI. In early January, the company completed a fresh round of financing, raising $20 billion. The company didn't disclose its valuation.

What other evidence has been released?

Musk's attorneys also pointed to private journal entries written by OpenAI's Brockman in 2017, obtained as part of legal discovery, as proof that the OpenAI founders "secretly had other plans" about the company's corporate structure, according to a recent court filing.

"We've been thinking that maybe we should just flip to a for profit," Brockman allegedly wrote in a private journal entry. "Making the money for us sounds great and all."

During a recorded deposition in September, Brockman was asked about this journal entry. "I believe this was a reference to having some sort of a revenue plan...in order to pursue the mission," he said.

News Corp, owner of The Wall Street Journal, has a content-licensing partnership with OpenAI.

This explanatory article may be periodically updated.

Write to Angel Au-Yeung at angel.au-yeung@wsj.com

(END) Dow Jones Newswires

January 28, 2026 08:27 ET (13:27 GMT)

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