The years-long legal battle between Elon Musk and OpenAI (OPAI.PVT) finally goes to court on Monday.

Jury selection in the lawsuit kicks off Monday in the US District Court for the Northern District of California, with opening arguments expected to begin Tuesday.

The witness list for both sides is a who’s who of tech heavyweights, including Musk, OpenAI CEO Sam Altman, and Microsoft CEO Satya Nadella. Depending on how the plaintiffs decide, Musk could take the witness stand as early as Tuesday.

The outcome of the case could have a significant impact on the AI industry and, if it goes Musk’s way, could derail OpenAI’s future IPO plans.

In his suit, Musk accuses Altman, OpenAI president Greg Brockman, and others of misleading him about the company’s plans to transition from a nonprofit to a for-profit business. Microsoft (MSFT), which has invested billions in OpenAI, is also named as a defendant in the case.

Turning OpenAI into a for-profit entity would allow it to issue shares in the business, enabling it to raise billions more in external funding that it could then use to purchase the computing power needed to develop and run increasingly powerful AI models.

Musk, who co-founded OpenAI in 2015 alongside Altman and Brockman, claims he donated more than $44 million to the company in its early years with the understanding that it would remain a nonprofit entity and says Altman and Brockman duped him when they moved to transition to a for-profit structure.

OpenAI has countered Musk’s claims, saying he was on board with the for-profit move but wanted to merge OpenAI with Tesla (TSLA) and become CEO. When Altman and Brockman balked at the suggestion, the company claims Musk decided to cut ties and form his own competing AI lab. Musk’s company, SpaceX (SPAX.PVT), recently acquired xAI in a deal ahead of its IPO.

OpenAI transitioned to a public benefit corporation (PBC) in October 2025. Microsoft, which Musk also names in his suit, received a 27% stake in the PBC, while OpenAI’s nonprofit arm, the OpenAI Foundation, received a stake valued at $130 billion. OpenAI’s most recent fundraising round valued the company at $852 billion.

The case is expected to run through mid-May. The jury’s verdict in the case will be advisory, leaving the ultimate decision up to US District Judge Yvonne Gonzalez Rogers.

If the defendants are found liable, Rogers will be tasked with ruling on potential remedies, which could include forcing OpenAI to roll back its for-profit transition.

The acrimonious relationship between Altman and Musk has frequently spilled into public view. Musk has repeatedly taken shots at the OpenAI CEO on his social platform X and offered to purchase OpenAI in February 2025 for $97.4 billion.