What had sounded two years ago like a spat between billionaires over a business they both co-founded has now reached an actual courtroom and jury trial, with jury selection beginning Monday in the civil suit that Elon Musk brought against OpenAI.

We learned in January that this case was likely headed to trial, and now the trial begins. Elon Musk is suing OpenAI, CEO and co-founder Sam Altman, and the company's president and another co-founder Greg Brockman over the company's pivot to being a for-profit enterprise behind his back — something that Altman and Brockman say that Musk was well aware of many years before this legal wrangling began.

While OpenAI began as a purely nonprofit venture, with a mission to use artificial intelligence to benefit humanity, the company has grown into an $852 billion enterprise, and Musk has gone on to found his own competitive AI company, xAI. The need to generate massive investment as well as revenue in order to operate AI models at scale was something Musk appeared to sign off on in emails that date back to 2018.

OpenAI officially restructured itself in the fall of 2025 as a public benefit corporation, or PBC, with the nonprofit OpenAI Foundation in control of the for-profit enterprise. And while there was some tension earlier in the year about whether the state was going to give its blessing to this, all seemed to be resolved in October, with California Attorney General Rob Bonta saying that his office had conducted "extensive negotiations with OpenAI, and we secured concessions that ensure charitable assets are used for their intended purpose."

OpenAI's attorneys have argued that Musk's lawsuit amounts to nothing more than "sour grapes" over the success of ChatGPT, and Musk's decision to depart the OpenAI board in February 2018. The reason at the time, ostensibly, was to avoid future conflicts of interest with Tesla. which was also developing AI technology, but there have been suggestions that Musk also left because of a failed attempt to take over OpenAI and run it himself.

As evidence of the sour grapes narrative, Musk and xAI are separately suing OpenAI and Apple over what he claims was an anticompetitive scheme to promote ChatGPT at the expense of chatbots like his, Grok — with the specific complaint that Grok was consistently ranked lower in Apple's App Store.

And the personal feud between Musk and Altman has played out fairly publicly, in part because Musk can't stop himself from tweeting when he's in a bad mood.

Case in point: Musk was doing some angry tweeting on January 20, including this one in which he referred to a spate of suicide cases saying, "Don’t let your loved ones use ChatGPT." Altman then replied at length, saying in part, "Sometimes you complain about ChatGPT being too restrictive, and then in cases like this you claim it's too relaxed." And Altman pointed out that Grok has plenty of safety issues of its own already, including the whole deepfake porn problem.

This week's trial dates back to March 2024, when Musk originally filed this lawsuit. And open arguments could begin as early as Tuesday, as CBS News reports, following jury selection today. Musk is seeking unspecified damages, but he has been said to be seeking between $79 billion and $134 billion in comepensatory damages — claiming that his early financial backing of and contributions to OpenAI entitle him to a large share of the company's current value.

OpenAI's Newsroom account on X said Monday, "We can't wait to make our case in court where both the truth and the law are on our side. This lawsuit has always been a baseless and jealous bid to derail a competitor."

The company adds, "We'll also finally have the chance to question Mr. Musk under oath before a jury of Californians about this attempt to undermine our work to ensure that artificial general intelligence benefits all of humanity."

Federal Judge Yvonne Gonzalez Rogers will be deciding the outcome of the case, with the jury serving in an advisory role.

Previously: It Looks Like Elon Musk's Suit Against OpenAI Over Abandoned Nonprofit Mission Is Headed to Trial

Top image: Elon Musk arrives at federal court  on March 4, 2026 in San Francisco, California. Musk is on trial in a  civil case for allegedly manipulating Twitter's stock price prior to his  purchase of the company in 2022. (Photo by Josh Edelson/Getty Images)