The first phase of the Musk v. Altman trial concluded proceedings in federal court in Oakland, California, on Thursday after attorneys for Elon Musk and OpenAI presented their closing arguments to the jury.

The nine-person jury, which is made up of six women and three men, will begin deliberating on Monday. The jury’s verdict will be advisory, which means Judge Yvonne Gonzalez Rogers will make the final decision on liability.

“You must decide the case solely on the evidence before you,” Gonzalez Rogers told the jury Thursday morning, in reading out the formal instructions. “You will recall you took an oath to do so.”

Musk sued OpenAI, its CEO Sam Altman and Greg Brockman, the company’s president, in 2024, alleging they went back on their commitment to keep the artificial intelligence startup a nonprofit and for unjustly enriching themselves. Musk, who co-founded OpenAI alongside Altman and Brockman in 2015, claims the roughly $38 million he donated to the company was used for unauthorized commercial purposes. 

During Thursday’s proceedings, Musk’s lawyer, Steven Molo, reiterated his arguments that OpenAI failed to open source its technology, prioritize AI safety and follow nonprofit customs and practices. He also claimed that OpenAI insiders and investors, including Altman, Brockman and Microsoft, enriched themselves at Musk’s expense. 

Sarah Eddy and William Savitt, attorneys for OpenAI, pushed back on Molo’s statements on Thursday. They said Altman and Brockman never made commitments to Musk about OpenAI’s corporate structure, and that Musk’s donations were spent and used properly. They also noted that the Tesla and SpaceX CEO filed the lawsuit only after launching his competing AI startup, xAI.  

“He never cared about the nonprofit structure,” Eddy told the jury. “What he cared about was winning.” 

Microsoft is also named as a defendant in the lawsuit, and attorney Russell Cohen presented the company’s closing arguments to the jury. Musk accused Microsoft, OpenAI’s principal investor, of aiding and abetting the company’s purported breach of charitable trust. Cohen said Microsoft had no knowledge of those events and couldn’t have participated in them. 

As the jury starts deliberations on Monday, the second stage of the trial, known as the remedies phase, will also begin. 

Gonzalez Rogers will hear arguments about the potential damages and next steps that should be taken if OpenAI, Altman and Brockman are found liable. The jury will not weigh in on this phase.

Musk has asked for a range of outcomes in the lawsuit since it was first filed in 2024. Most recently, he asked the judge to consider removing Altman and Brockman from their roles at OpenAI, and to unwind the company’s 2025 recapitalization. 

In January, Musk’s lawyers said their client was entitled to up to $134 billion in damages from OpenAI and Microsoft, calling them “wrongful gains.” His team now says any “ill-gotten gains” should be returned to OpenAI’s foundation.

There will only be a decision in the remedies phase if there’s a finding of liability. 

Gonzalez Rogers has presided over prior high-profile technology cases, which could explain why she chose to enlist the help of an advisory jury.

“Judges normally empanel advisory juries when they either want the community judgment of the jurors or they want ‘cover’ in a highly visible case,” Steven Baicker-McKee, an associate law professor at Duquesne University, told CNBC. 

Former President Barack Obama appointed Gonzalez Rogers to U.S. District Court for the Northern District of California in 2011, and she previously oversaw the antitrust case between Epic Games and Apple.

Gonzalez Rogers showed little patience for any shenanigans from the lawyers during the first phase of the Musk v. Altman trial, repeatedly chiding representatives for both parties when they stepped out of line. 

“You do not want to be held in contempt I guarantee you,” she warned one lawyer on Tuesday.

With the jurors, however, Gonzalez Rogers has been warm and friendly, cracking jokes and even bringing them chocolates on one occasion. She concluded Thursday’s proceedings by reminding the jury that lunch will be provided during deliberations.

—CNBC’s Kate Rooney contributed to this report.

WATCH: It’s the final full day of testimony in the Musk vs. OpenAI trial: Here’s what to know

Microsoft CEO Satya Nadella took the stand to testify in the Musk v. Altman trial in federal court in Oakland, California, on Monday. 

Nadella, wearing a navy suit with a blue tie, began his testimony by answering questions about his role at Microsoft and the early days of the company’s strategic partnership with OpenAI.

In 2024, Elon Musk sued OpenAI, its CEO, Sam Altman, and its president, Greg Brockman, alleging that they went back on their vow to protect the artificial intelligence company’s nonprofit structure and follow its charitable mission. Microsoft is named as a defendant in the lawsuit, as Musk accuses the company of aiding and abetting OpenAI’s purported breach of charitable trust. 

Microsoft has been one of OpenAI’s major backers since 2019, years before the company rocketed into the mainstream with the launch of its ChatGPT chatbot in late 2022. Microsoft’s more than $13 billion worth of investments in OpenAI, including a $1 billion investment in 2019, a $2 billion investment in 2021 and $10 billion in 2023, have come up repeatedly over the course of the trial. 

Musk, who testified late last month, said Microsoft’s $10 billion investment was the key tipping point that made him believe OpenAI was violating its nonprofit mission. He testified that the scale of the investment bothered him, and it prompted him to open a legal investigation into OpenAI. 

“I was concerned they were really trying to steal the charity,” Musk said from the stand.

Musk co-founded OpenAI alongside Altman, Brockman and a handful of other executives and researchers in 2015. After a number of disagreements about OpenAI’s direction, including a failed effort to join it with his automaker Tesla, Musk left the OpenAI board in 2018. He went on to launch a competing AI startup, xAI, which he merged with SpaceX earlier this year. 

OpenAI established a for-profit subsidiary in the months following Musk’s departure, which allowed the company to raise outside funding more easily. Investors, including Microsoft, have since poured billions of dollars into OpenAI’s for-profit arm, and the company’s valuation has swelled to more than $850 billion. 

In October, OpenAI completed a recapitalization that cemented its structure as a nonprofit with an equity stake in its for-profit business. As part of that announcement, Microsoft disclosed that it held a roughly 27% stake in OpenAI’s for-profit unit that was valued at around $135 billion.

The relationship between OpenAI and Microsoft has shown signs of strain in recent months, even as both companies continue to tout it as strategic and core to their businesses. Late last month, the same day that jury selection kicked off in Musk v. Altman, the companies announced a revamped partnership agreement that allows OpenAI to cap revenue share payments and serve customers across any cloud provider.

OpenAI said in a release that the agreement aimed to “simplify our partnership and the way we work together.”

Musk testified that he is not entirely against OpenAI having a for-profit unit, but he said it became “the tail wagging the dog.” He repeatedly accused Altman and Brockman of enriching themselves from a charity while also reaping the positive associations that come from running a nonprofit.

“Microsoft has their own motivations, and that would be different from the motivations of the charity,” Musk said from the stand. “All due respect to Microsoft, do you really want Microsoft controlling digital superintelligence?”

During a videotaped deposition shown in court last week, former OpenAI director Tasha McCauley recalled a discussion with Nadella and her fellow board members after the 2023 decision to dismiss Altman as OpenAI’s CEO.

“To the best of my recollection, Satya wanted to restore things to as they had been,” McCauley said. The board members didn’t think that was the right move, she said.

— CNBC’s Jordan Novet contributed to this report.

WATCH: The Musk vs. OpenAI trial is underway — here’s where things stand

A week into the Musk v. Altman trial, which features two towering figures in the tech industry facing off in a case that could have major implications for OpenAI, the plaintiff has made his central message clear to the jury. 

“You can’t just steal a charity,” Elon Musk, the world’s richest person, said repeatedly during his time on the stand at a federal courthouse in Oakland, California. 

Musk’s testimony was the centerpiece of the trial’s first week. It comes two years after the Tesla and SpaceX CEO first sued OpenAI CEO Sam Altman and Greg Brockman, the company’s president, alleging they went back on their promises to keep the artificial intelligence startup a nonprofit and to follow its charitable mission.

Musk, who helped start OpenAI in 2015 as a nonprofit, claims that the roughly $38 million he donated to the project was used for unauthorized commercial purposes. OpenAI, now valued at over $850 billion by private investors, has 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 Monday with the seating of a nine-person jury. Attorneys for both parties presented opening arguments on Tuesday. The main event was Musk’s testimony, which stretched over the course of three days, wrapping up on Thursday. 

The courtroom was dark on Friday, and proceedings will resume next week, with Judge Yvonne Gonzalez Rogers, an appointee of former President Barack Obama, presiding over the case. Altman and Brockman are expected to testify later this month.

After Musk left OpenAI, the AI lab began moving more towards commercialization, creating a for-profit subsidiary in 2018. The business started booming after the launch of ChatGPT in late 2022, and the subsequent raising of $10 billion in equity from Microsoft. 

Musk testified that he is not entirely against OpenAI having a for-profit unit, but he said it became “the tail wagging the dog.” He repeatedly accused Altman and Brockman of enriching themselves from a charity while also reaping the positive associations that come from running a nonprofit.

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

Musk said he started OpenAI to serve as a “counterweight” to Google, which he viewed as having insufficient concerns surrounding AI safety. Musk said he got into an argument about the subject with Google co-founder Larry Page, a former friend, who called him a “speciesist for being pro-human.”

Musk said OpenAI wouldn’t exist without him. 

“I came up with the idea, the name, recruited the key people, taught them everything I know, provided all the initial funding,” Musk said.

In a January filing, Musk’s attorneys 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 OpenAI’s foundation.

Musk is also seeking to have Altman and Brockman removed from their roles and to “unwind OpenAI’s for-profit conversion and restructuring.” 

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

Following the end of Musk’s testimony on Thursday, his lawyers called Jared Birchall, who manages Musk’s family office, as their next witness.

Birchall testified about the specific donations Musk made to OpenAI, as well as his knowledge about 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 effort that Altman immediately rejected.

Before the proceedings kicked off on Monday, Gonzalez Rogers opted to split the trial into two parts: a liability phase to determine whether any wrongdoing occurred, and a remedies phase to decide the appropriate outcomes and next steps. Gonzalez Rogers expects the former to conclude by May 21

The jury will weigh in during the liability phase only, and its verdict will be advisory, which means Gonzalez Rogers will make the final decision.

—CNBC’s Lora Kolodny contributed to this report.

WATCH: Musk fires back at OpenAI attorney

The nine-person jury was seated on Monday in the high-stakes legal battle between longtime friends turned rivals Elon Musk and Sam Altman at a federal courthouse in Oakland, California.

Judge Yvonne Gonzalez Rogers is overseeing the proceedings between the world’s richest person and the CEO of OpenAI. Opening arguments are scheduled to begin on Tuesday, and CNBC is in the courtroom for the proceedings. 

Musk, who co-founded OpenAI in 2015, sued the company, Altman and Greg Brockman, OpenAI’s president, in 2024, alleging they reneged on their commitments to keep the artificial intelligence lab a nonprofit and follow its charitable mission. OpenAI has repeatedly dismissed Musk’s lawsuit as “baseless.” Musk left OpenAI’s board in 2018, and five years later started xAI as a rival, merging that company with SpaceX earlier this year.

Musk has sought a number of different remedies over the course of the case, including the removal of Altman and Brockman from their roles at OpenAI. Musk’s lawyers said in January that he should receive up to $134 billion in “wrongful gains,” though he has since asked to funnel those funds back into the OpenAI charity. 

Gonzalez Rogers opted to divide the trial into two parts: a liability phase to decide if any wrongdoing occurred, and a remedies phase to determine the appropriate damages and next steps. The jury will weigh in during the liability phase only, and its verdict will be advisory, which means Gonzalez Rogers will make the final decision in both sections of the trial. 

The liability phase of the trial is expected to wrap up by May 21, Gonzalez Rogers said Monday.

Gonzalez Rogers started the proceedings by welcoming the prospective jurors to the courtroom. She cracked some jokes as she explained the case laid out the trial’s schedule.

Lawyers grilled prospective jurors on their views on AI, Musk and Altman. Some confessed to holding negative views of Musk due to his political ideology.

“The reality is people don’t like him,” Gonzales Rogers said at one point. She expressed confidence that the jurors selected will respect the judicial process and the facts of the case.

Altman and Brockman were in the courtroom on Monday.

Musk alleges in his lawsuit that he was “assiduously manipulated” and “deceived” by OpenAI, Altman and Brockman and their promises to “chart a safer, more open course than profit-driven tech giants.” He has asked the judge to consider unwinding the company’s recent restructuring, which cemented its structure as a nonprofit with a controlling stake in its for-profit business.

Musk and Altman have been in a public war of words for months leading up to the trial. That continued on Monday, with Musk writing in a post on X, “Scam Altman and Greg Stockman stole a charity. Full stop.”

The comment followed a post from the OpenAI Newsroom account.

“We can’t wait to make our case in court where both the truth and the law are on our side,” OpenAI wrote. “This lawsuit has always been a baseless and jealous bid to derail a competitor.”

Of the 26 claims that Musk asserted in 2024, only two remain: unjust enrichment and breach of charitable trust. Musk’s lawyers dismissed two of the claims, fraud and constructive fraud, ahead of the trial in an effort to “streamline the case,” according to a filing

The trial lands as Musk prepares to take SpaceX public in what’s likely to be a record IPO and as OpenAI gears up for its own expect public offering later this year. The two companies combined are valued at over $2 trillion on the private market.

— CNBC’s Lora Kolodny contributed to this report.

WATCH: Elon Musk and Sam Altman go to court next week — here’s what to expect from the trial

Apple announced on Monday that CEO Tim Cook will be replaced by John Ternus. Executives across the tech industry and beyond began reacting to the transition shortly after the news broke.

Cook has served as the iPhone maker’s CEO for nearly 15 years, after late founder Steve Jobs resigned in 2011.

“Tim Cook is a legend,” OpenAI CEO Sam Altman posted on X. “I am very thankful for everything he has done and I am very thankful for Apple.”

Apple and OpenAI first partnered in 2024, integrating ChatGPT into Siri and Apple’s writing tools.

Palmer Luckey, founder of Oculus VR, also posted on X, writing “RIP Tim Apple,” referring to the famous White House incident with President Donald Trump in 2019.

Trump mistakenly addressed Cook as “Tim Apple” during his first term. Cook made light of the remark, replacing his last name with the Apple logo on his Twitter profile.

Luckey left Facebook in 2017 and founded defense contractor Anduril later that year.

Warren Buffett, chairman of Berkshire Hathaway, told CNBC’s Becky Quick that “Apple would not be the Apple of today without Tim Cook.”

“What he has done with Apple could not be done by anybody I’ve known,” Buffett said. Apple is Berkshire Hathaway’s largest shareholding.

“Covering the world and getting along with countries with all kinds of histories and doing right by the customer, people who worked for him, certainly the shareholders, which we were lucky enough to be one of… he’s one of a kind,” Buffett said.

Ternus, currently a senior vice president of hardware engineering, will become CEO effective Sept. 1. Cook will then assume the role of executive chairman.

Elon Musk is seeking to have OpenAI CEO Sam Altman and President Greg Brockman removed from their roles as officers in the company as part of a case that’s expected to go to trial later this month.

In a legal filing on Tuesday, Musk’s lawyers laid out specific remedies their client is seeking if a judge and jury determine that Altman and OpenAI defrauded Musk, the world’s richest person.

Musk sued Altman and OpenAI in 2024, claiming the artificial intelligence company that he helped start almost a decade earlier “assiduously manipulated” and “deceived” him into donating $38 million, based on promises that the entity would remain a nonprofit. The two sides have since been embroiled in a public war of words, in addition to their legal battle and budding business rivalry.

“Plaintiff will seek an order removing Altman as a director from the OpenAI nonprofit board and removing both Altman and Brockman as officers of the OpenAI for-profit,” Musk’s lawyers said in Tuesday’s filing. “Removal of a charity’s officers and directors is a common remedy where those individuals fail to protect or carry out the charity’s public mission.”

Musk is also asking the court to make OpenAI revert to operating as an actual nonprofit, according to the filing. The company completed a restructuring in October, and is now run as a nonprofit with a 26% stake in the for-profit arm, which includes ChatGPT.

Jury selection for the case is slated to begin on April 27, in a federal court in Oakland, California.

Following Tuesday’s filing, OpenAI said in a post on X that Musk is “pretending to change his tune about attacking the nonprofit OpenAI Foundation.”

“The truth is that this case has always been about Elon generating more power and more money for what he wants,” OpenAI said. “His lawsuit remains nothing more than a harassment campaign that’s driven by ego, jealousy and a desire to slow down a competitor.”

Musk, Altman and others co-founded OpenAI as a nonprofit AI lab in 2015. Musk left OpenAI in 2018, after trying to convince executives there to merge it with Tesla, his electric vehicle company.

In 2023, Musk launched a competing company called xAI, which developed the AI image generator and chatbot Grok. In February, Musk’s SpaceX acquired xAI, which also owns X (formerly Twitter) in a deal that valued the combined entity at $1.25 trillion. SpaceX recently filed confidential paperwork with the SEC for what will likely be a record IPO.

On Monday, OpenAI sent a letter to the California and Delaware attorneys general, urging them to investigate “improper and anti-competitive behavior” by Musk and his associates ahead of the trial. In the letter, OpenAI strategy chief Jason Kwon alleged that Musk has been working to undermine OpenAI through various “attacks” on the company, including by “coordinating his efforts” with Meta CEO Mark Zuckerberg.

Musk’s attorneys previously said, in a January filing, that their client should receive up to $134 billion in damages from OpenAI ⁠and lead investor Microsoft, calling them “wrongful gains” that the companies had received as a result of his early work with and financial support of OpenAI.

In Tuesday’s filing, Musk’s lawyers said their client is seeking “to return all ill-gotten gains, including Microsoft’s, to the OpenAI charity.”

— CNBC’s Ashley Capoot contributed to this report.

WATCH: OpenAI is chasing Anthropic

OpenAI CEO Sam Altman met with a handful of lawmakers in Washington, D.C. where Sen. Mark Kelly, D-Ariz., said he raised some “serious questions” about the company’s approach to warfare and its recent deal with the Department of Defense.

In an interview with CNBC’s Emily Wilkins, Kelly said the group talked “in detail” about surveillance and how artificial intelligence systems could be used within a kill chain. He called it a “good discussion.”

“There’s got to be guardrails in place, and we’ve got to make sure that we’re always thinking about the Constitution and making sure that we comply with it,” Kelly said.

OpenAI formed a deal with the DOD late last month just hours after rival Anthropic had been blacklisted by Defense Secretary Pete Hegseth, who declared the company a “Supply-Chain Risk to National Security.”

Anthropic had been trying to renegotiate its contract with the DOD, but the talks stalled over a disagreement about how the technology could be used. The DOD wanted Anthropic to grant the military unfettered access to its models for all lawful purposes, while Anthropic sought assurance that its models would not be used for fully autonomous weapons or domestic mass surveillance.

Altman said in a post on X the day the deal fell apart that prohibitions on domestic mass surveillance and human responsibility for the use of force, including for autonomous weapon systems, are two of the company’s “most important safety principles.” He said the DOD agreed and put them into the arrangement.

OpenAI published an excerpt of its contract with the DOD, which says that the agency “may use the AI System for all lawful purposes.” The company said it’s confident the DOD will not be able to use its AI systems for mass surveillance or fully autonomous weapons because of OpenAI’s safety stack, the contract language and existing laws.

“We think it’s very important to support the United States government and the democratic process,” Altman told CNBC on Thursday. He added that while OpenAI disagrees with the Pentagon’s decision to designate Anthropic a supply chain risk, he thinks the government needs to be able to make decisions about “how the most important things in the country are going to work.”

The clash between Anthropic and the DOD came as a shock to officials and technologists in Washington. Many had come to view Anthropic’s models as superior — they were the first to be deployed in the agency’s classified networks — and championed the company’s ability to integrate with existing defense contractors like Palantir. 

Kelly is working with other senators to draft legislation that would set guardrails around DOD contracts with AI organizations, and said that Congress “needs to have a role.”

“We need to have legislation on this that creates some of these boundaries, guardrails,” he said. “This is the United States Congress, things don’t move as fast as we would like, but this technology is moving very quickly.”

WATCH: Sam Altman on meeting with lawmakers: Economic impact on jobs will be a huge topic

OpenAI CEO Sam Altman told employees in an all-hands meeting on Tuesday that the company doesn’t “get to make operational decisions” regarding how its artificial intelligence technology is used by the Department of Defense.

“So maybe you think the Iran strike was good and the Venezuela invasion was bad,” Altman said Tuesday, according to a partial transcript of the meeting reviewed by CNBC. “You don’t get to weigh in on that.”

The meeting occurred four days after OpenAI announced its DOD arrangement, which landed just hours before the U.S. and Israel began carrying out strikes against Iran.

Altman told employees that the Pentagon respects OpenAI’s technical expertise, wants input about where its models are a good fit and will allow the company to build the safety stack it deems appropriate, according to a person familiar with the matter who asked not to be named because the meeting was private.

But Altman said the agency has also made it clear that operational decisions rest with Secretary Pete Hegseth. Altman has been vocally criticized, including by some OpenAI employees, since announcing the deal with the Pentagon shortly after rival Anthropic was blacklisted and labeled a “Supply-Chain Risk to National Security.” President Donald Trump also directed every federal agency in the U.S. to “immediately cease” all use of Anthropic’s technology.

Anthropic’s AI was reportedly used in the Iran strikes over the weekend as well as for the capturing of ousted Venezuelan leader Nicolás Maduro and his wife, Cilia Flores, in January.

Altman has defended OpenAI’s contract in various social media posts, though he conceded that it looked “looked opportunistic and sloppy” and that the company “shouldn’t have rushed to get this out on Friday.” He said in a post on X that day that the Pentagon “displayed a deep respect for safety and a desire to partner to achieve the best possible outcome.”

Anthropic was the first lab to deploy its models across the DOD’s classified network, and had been trying to negotiate the ongoing terms of its contract before talks collapsed. The company wanted assurance that its models would not be used for fully autonomous weapons or mass surveillance of Americans, while the DOD wanted Anthropic to agree to let the military deploy the models across all lawful use cases.

Last year, OpenAI was awarded a $200 million contract by the Pentagon, which allowed the agency to begin using the startup’s models in nonclassified use cases. The new arrangement will allow the company to deploy its models across the department’s classified networks.

Elon Musk’s xAI has also agreed to deploy its models across classified use cases.

“I believe we will hopefully have the best models that will encourage the government to be willing to work with us, even if our safety stack annoys them,” Altman said Tuesday. “But there will be at least one other actor, which I assume will be xAI, which effectively will say ‘We’ll do whatever you want.'”

Altman and Musk, two of the co-founders of OpenAI, are engaged in a heated legal battle that’s slated to go to trial next month.

XAI didn’t immediately respond to a request for comment.

— CNBC’s Kate Rooney contributed to this report.

WATCH: OpenAI could profit handsomely from Pentagon deal, says Big Technology’s Alex Kantrowitz