Musk Takes the Stand in $134B OpenAI Trial

On April 28, 2026, inside a federal courthouse in Oakland, California, the most consequential technology trial in recent memory opened with a statement that cut right through the legal complexity. Elon Musk took the witness stand, looked at the nine-person advisory jury, and said: "It is not okay to steal a charity, that's my view."

Those words set the tone for a case that could reshape the entire structure of artificial intelligence in America, strip the leadership of the world's most valuable AI company, and determine whether a trillion-dollar IPO ever happens.

The backstory starts in 2015. Musk was a co-founder of OpenAI, a nonprofit research lab built on the premise that artificial intelligence was too dangerous to be controlled by any single corporation. The specific competitor Musk had in mind was Google, whose acquisition of DeepMind had alarmed him. OpenAI was supposed to be the counterweight, a publicly beneficial institution with no shareholders to answer to and no profit motive to corrupt its research. Musk contributed roughly $44 million in donations and in-kind support during the organization's early years. He says he did all of that on the explicit understanding that OpenAI would remain a nonprofit forever.

He told the jury: "I specifically chose to make it something for the benefit of all humanity."

OpenAI today is a very different organization. Its February 2026 funding round raised $110 billion and valued the company at approximately $852 billion, making it one of the most valuable private enterprises on Earth. The company is now converting from a nonprofit into a for-profit public benefit corporation, and it is targeting a $1 trillion valuation for a planned 2026 IPO. That transformation is what Musk sued to stop.

The lawsuit seeks $134 billion in what his legal team calls ill-gotten gains. But Musk renounced all personal monetary damages entirely. If he wins, any financial award goes directly to OpenAI's nonprofit foundation, not to Musk personally. What he actually wants from the court is structural: he wants Sam Altman and Greg Brockman removed from leadership, and he wants the for-profit conversion reversed.

He made the stakes explicit on the stand: "If we make it OK to loot a charity, the entire foundation of charitable giving in America will be destroyed."

That is a jury argument, and it tells you something about how Musk's team is approaching this case. They want the nine-person advisory jury to feel that a loss for Musk is a loss for every donor in America, not just a loss for a billionaire who regrets leaving a company that grew beyond him.

The trial opened before Judge Yvonne Gonzalez Rogers in the Northern District of California. The nine jurors advise on monetary damages, but Judge Gonzalez Rogers alone will decide on the structural remedies.

Both attorneys came to the podium with quotable lines. Musk's lead attorney, Steven Molo, told the jury: "The defendants stole a charity." OpenAI's lead counsel, William Savitt, offered the counter-argument: "We are here because Mr. Musk didn't get his way at OpenAI. That's what happened. He quit, saying they would fail for sure. But my clients had the nerve to go on and succeed without him."

That is the credibility contest this trial comes down to. Either the founders broke a foundational promise and Musk is exposing it, or Musk is a competitor using the legal system to attack a company he could not control.

Musk described his own founding role in sweeping terms while on the stand. He said he came up with the original idea, coined the name OpenAI, recruited the key early personnel, shared his technical knowledge with the team, and provided essentially all of the initial funding.

Musk originally filed 26 separate claims against OpenAI and its leadership. Before trial began, Judge Gonzalez Rogers dismissed the vast majority of them, including RICO charges, fraud, antitrust, and breach of contract. Only two claims survived: breach of charitable trust and unjust enrichment. That narrowing is significant. A judge who has spent years reviewing these filings found most of Musk's legal theories insufficient to take to a jury.

Nonprofit law professor Sam Brunson of Loyola University Chicago explained the core legal challenge: "As a general rule, the answer to that is no. If I donate to an organization, I've given up that money, and if it turns out that I don't like what they do subsequently, my recourse is to stop donating to them." Fortune magazine described this as "a trial almost no one thinks Musk can win."

But the evidence is not all running in OpenAI's direction. The most striking single exhibit entered so far did not come from Musk's lawyers. It came from the defense's own files. Greg Brockman's 2017 personal diary is Exhibit A in the case. The entries are candid in ways that create real problems for OpenAI. Brockman wrote that accepting Musk's terms would "nuke" their economics. More damaging still, he wrote that Musk's own account of the founding negotiations would correctly show that the founders were not honest with him. A co-defendant's private journal, acknowledging that Musk may have been misled, is now sitting in front of a federal jury.

OpenAI's defense has its own documentary answer. An email from Shivon Zilis, a former OpenAI board member, describes two restructuring options that were allegedly presented to Musk at some point: a B-corp or a C-corp structure alongside the existing nonprofit. OpenAI argues Musk was shown these paths and did not object. Musk's team disputes both the characterization and the timeline.

The financial stakes extend far beyond the two named parties. Microsoft holds approximately 27% equity in OpenAI Group PBC, currently valued at roughly $135 billion. Musk's lawsuit asks the court to require Microsoft to disgorge that position, which is why Microsoft CEO Satya Nadella is on the witness list. Combined investments from Amazon, Microsoft, SoftBank, and Nvidia total roughly $200 billion, all of which face serious uncertainty if a court orders OpenAI to revert to nonprofit status. The $110 billion funding round raised just weeks before trial would face clawback questions. The planned IPO targeting $1 trillion in valuation would be blocked entirely. This case is about whether the most powerful AI company in the world gets to go public.

Among the major witnesses scheduled are Sam Altman, Microsoft CEO Satya Nadella, OpenAI co-founder Ilya Sutskever, and former OpenAI CTO Mira Murati, who will appear via videotaped deposition. But the most anticipated appearance may be Shivon Zilis, the former OpenAI board member who is also the mother of four of Musk's fourteen children. Zilis is expected to be on the stand longer than any other witness. Musk's lawyers plan to use her testimony to corroborate the early nonprofit commitments he says were made. OpenAI's lawyers intend to argue she was passing company information back to Musk during her board tenure, a conflict-of-interest claim that attacks the credibility of both witnesses at once.

The personal dimensions of this case have already created friction inside the courtroom. Judge Gonzalez Rogers issued a warning to Musk about his ongoing "Scam Altman" posts on X during the active trial. OpenAI's lawyers have also secured court permission to question Musk about his attendance at Burning Man in 2017, where some of the most disputed restructuring conversations allegedly occurred.

There is also the matter of motive, and OpenAI's lawyers intend to press it hard. Musk now runs xAI, his own artificial intelligence company that competes directly with OpenAI for talent, customers, and investment. OpenAI's lead counsel told the jury that Musk's motivations in this lawsuit are driven by the fact that he is now a direct commercial competitor. The defense argument is that this lawsuit is a competitive strike dressed in the language of charitable trust law. Musk is betting that the Brockman diary makes that framing impossible to sustain.

The competitive dynamic matters beyond just this case. Anthropic, Google, and Amazon all stand to benefit asymmetrically if OpenAI is forced to revert to nonprofit status and its IPO is blocked. With the best-capitalized commercial AI competitor removed from the public market, the competitive landscape shifts significantly.

On the same day Musk took the stand, Sam Altman appeared virtually at an Amazon Web Services event and told the audience he wished he could be there in person. Whatever happens in Oakland, the company's commercial relationships are moving forward, and partners are not spooked.

Emails entered into evidence include an exchange from February 2023, well after OpenAI's commercial direction was set. Altman wrote to Musk expressing that the public attacks on OpenAI were deeply painful. Musk replied: "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." Two men who once shared a founding vision, now exchanging emails about hurt feelings and the fate of civilization while their companies compete for the same customers. That exchange tells you something about how this fell apart.

Did the founders of OpenAI commit to a permanent nonprofit structure, and then break that promise as the company became too valuable to remain one? Or did Musk invest in an idea, lose influence as the organization grew, quit when he could not take control, and now want the courts to punish the people who built something extraordinary without him?

The trial is expected to last four weeks. The Brockman diary will survive cross-examination, or it will not. That diary is the single piece of evidence most likely to determine whether Musk's case holds together. If it holds, and the jury comes away believing the founders were not honest with him, this case becomes something very different from the long-shot almost every legal expert predicted.

For the first time, the people who built the most powerful AI company in the world are being asked, under oath, to explain EXACTLY how it happened. And whether they can tell the same story now as they told each other in private.