A nine-person jury is set to decide whether Elon Musk’s allegations of “stealing a charity” against Sam Altman and OpenAI are legitimate, with deliberations to begin in earnest on Monday. Whatever its outcome, the case has been an illuminating, at times exhausting, look behind the scenes at the history of OpenAI and how some of the most powerful figures in the tech industry operate.

Attorneys for both sides have introduced reams of private text messages, emails and even diary entries to support their arguments. A who’s who of Silicon Valley testified in the trial, including Microsoft CEO Satya Nadella and the mother of some of Musk’s children, Shivon Zilis. Both Altman and Musk also took the stand for hours, facing combative cross-examinations that painted them each as untrustworthy.

Over the course of three weeks in an Oakland, California, federal courthouse, the trial has pit the richest person in the world against the biggest names in artificial intelligence. It has provided moments of embarrassment for both tech moguls and underscored just how bitter the feud between them has become.

The core of Musk’s case revolves around allegations that Altman, OpenAI and its president, Greg Brockman, broke a founding agreement of the AI firm, established as a non-profit in 2015, when they later restructured it into a for-profit entity. Musk claims that he was swindled by Altman, who lured Musk in as a co-founder and took his financial backing, then twisted the company for personal gains. Musk’s suit claims a breach of charitable trust and unjust enrichment by Altman and Brockman.

As the trial progressed, a mix of academic experts and tech industry bigwigs all weighed-in on Musk’s allegations. Collectively, they presented two differing accounts of OpenAI’s history: one where an impatient Musk left the company he knew would eventually seek profit, and another where Altman pursued power while deceiving anyone necessary in order to attain it.

OpenAI has denied all of Musk’s allegations, arguing that not only was he aware of plans to create a for-profit entity but that he made a failed bid to take total control of the company, departed it in a huff in 2018, and founded a competitor, xAI. OpenAI has cast Musk as a sore loser in the AI race who is seeking revenge through the suit. The AI firm also maintains that its for-profit arm is still overseen by a non-profit, which its lawyers repeatedly described as one of the most well-resourced charitable organizations in the world.

Musk is seeking the removal of Altman and Brockman, the undoing of OpenAI’s for-profit restructuring and the redistribution of $134bn from its for-profit entity to its non-profit organization. If the jury finds OpenAI is liable, the verdict could present sizable difficulties for the company, which is seeking to go public later this year at a valuation of $1tn.

Musk blows up, takes off

The first marquee witness in the trial was Elon Musk himself, whose attorney called him to the stand in the opening week of proceedings. Musk testified for three consecutive days about his allegations against Altman, at times becoming combative and raising his voice during moments of frustration.

Musk’s testimony began with friendly questioning from the Tesla CEO’s lead attorney, Steven Molo, who allowed Musk to recap his career and present his story of OpenAI’s beginnings. In Musk’s retelling, he was the primary reason that the company ever got off the ground. He claimed the startup’s founding mission to better humanity was borne out of his fear that Google could not be trusted to develop artificial intelligence. He argued that his benevolent hopes for OpenAI were dashed by a conniving Altman, who seized control of the company and abandoned its charitable mission in pursuit of profit.

“They’re going to make this lawsuit very complicated, but it’s actually quite simple,” Musk said. “Which is: it’s not OK to steal a charity. That’s my view.”

The testimony took a turn as soon as Musk’s cross-examination began, with OpenAI’s lead attorney, William Savitt, prodding him with rapid-fire questions about what he knew about the AI firm’s for-profit plans and when he knew them. The judge cautioned Musk not to give meandering answers; at points, he became testy, once likening Savitt’s questions to being asked “have you stopped beating your wife”, eliciting a rebuke from the bench.

“Your questions are not simple. They are designed to trick me, essentially,” Musk said to Savitt.

Musk wasn’t present for remaining parts of the trial and, despite Judge Yvonne Gonzalez Rogers’s order that he remain ready to be recalled as a witness, he joined Donald Trump this week on a diplomatic trip to China.

“Mr Musk isn’t here today. My clients are,” OpenAI’s lawyer said during his closing arguments on Thursday. “Mr Musk came to this court for exactly one witness: Elon Musk. Now he’s in parts unknown.” Musk’s lawyer sheepishly apologized for his client’s absence.

A long list of people calling Sam Altman a liar

After Musk’s testimony at the start of the trial, the centibillionaire’s lawyers presented several video depositions and called a series of witnesses in an attempt to show that Altman was not trustworthy in his dealings at OpenAI. Several of the company’s former top executives took the stand, often being called on to rehash a five-day period in 2023 when Altman was fired by the OpenAI board before being reinstated amid a power struggle.

While it didn’t focus on the case’s granular questions of breaching a charitable trust, this portion of the trial repeatedly painted an unflattering portrait of Altman as a deceptive operator. Former chief technical officer Mira Murati described Altman as often “saying one thing to one person and completely the opposite to another person”, while former board member Natasha McCauley accused Altman of creating “repeated crisis events” through his leadership.

OpenAI co-founder and former chief scientist Ilya Sutskever was questioned by Musk’s lawyer Molo about statements in his deposition and his concerns about Altman’s dishonesty.

“You told the board that Altman ‘exhibits a consistent pattern of lying, undermining his execs and pitting his execs against one another’,” Molo asked.

“Yes,” Sutskever responded.

Sutskever, McCauley and Murati were all involved in the 2023 attempt to push out Altman and have since left the company.

When Altman took the stand in the final week of the trial, he first presented his own version of OpenAI’s history and Musk’s involvement. Altman argued that Musk was a difficult, erratic co-founder who demoralized staff with an aggressive management style and sought power for himself. At one point, Altman alleged, Musk wanted “total control” over the company and once suggested that power could be passed down to his children when he died.

Altman also took aim at Musk’s mantra that his rival stole a charity, claiming that OpenAI built one of the largest charities in the world and that it was Musk who was intent on destroying it.

“This whole ‘you can’t steal a charity’. I agree you can’t steal it. Mr Musk did try to kill it,” Altman said.

During cross-examination, Musk’s lawyer again pressed Altman on whether he was trustworthy and read out earlier testimony from former colleagues denigrating his character.

“You’ve repeatedly been called deceptive and a liar by people with whom you’ve done business, right?” Musk’s lawyer asked.

“I have heard people say that,” Altman responded.

‘Amateur city’, Musk’s partner and a personal diary

Beyond Musk and Altman, jurors heard from OpenAI president Brockman, Microsoft CEO Nadella and former OpenAI board member-turned Musk romantic partner Zilis. Each delivered some of the most memorable moments of the trial.

Nadella, who was called because Microsoft is OpenAI’s primary business partner and is also accused in the suit of aiding and abetting OpenAI’s breach of trust, took the stand on Monday. He discussed his own role in OpenAI’s development and in one remark took a dig at the board members who tried to oust Altman in 2023 – saying that they couldn’t communicate their rationale and threw the company into chaos.

“It was sort of amateur city, as far as I’m concerned,” Nadella testified. “I was very worried that the employees were going to leave en masse.”

Brockman, meanwhile, faced scrutiny over a personal diary he kept during the founding years of OpenAI and which contained entries like “financially, what will take me to $1bn?” Musk’s lawyers presented the diary as proof of a callous ambition and an intent to deceive their client, while OpenAI framed it as a cherry-picked, stream-of-consciousness document that proved nothing. Either way, Brockman did not seem happy about it becoming public.

“It’s very painful,” Brockman said. “It’s very deeply personal writings that weren’t meant for the world to see, but there’s nothing in there that I’m ashamed of.”

The trial became even more personal when Zilis, who is the mother of four of Musk’s children and an executive at Neuralink, took the stand. OpenAI’s lawyers accused her of acting as an insider source for Musk while she was on the board of OpenAI, funneling him information while hiding her romantic involvement with the billionaire. Zilis denied ever acting as a spy for Musk.

At one point in Zilis’s testimony, lawyers brought up a text exchange between her and a friend after it became public that Musk was starting his own AI company in 2023 and she left OpenAI’s board. Like much of the trial, it offered a glimpse of the strange reality that the world’s tech elite live within.

“E’s effort has become well known,” Zilis texted.

“Fuck,” the friend responded. “You ok.”

“When the father of your babies starts a competitive effort and will recruit out of openai there’s nothing to be done,” Zilis replied.