Elon Musk sued OpenAI, the company he helped launch in 2015 alongside Sam Altman and others, claiming that Altman and fellow co-founder Greg Brockman cut him out and steered the nonprofit toward a for-profit model without his OK. Musk’s team says OpenAI’s board, dominated by Altman and Brockman, violated their fiduciary duties when they raised more than $10 billion from Microsoft and others and handed those investors control over key technology. He’s demanding “billions of dollars” in damages and a seat back on the board. OpenAI responds that Musk left the board in 2018, long before the company inked its deals or launched its most lucrative products. Their lawyers insist he had no right to block the shift to a capped-profit structure or the sale of so-called “super-voting” shares to Microsoft. They argue Musk is really upset about losing the chance to capitalize on ChatGPT’s success and is trying to rewrite history in court. Over the past year, both sides have dug through emails and board minutes. Musk’s lawyers point to messages in which Altman and Brockman said they’d keep Musk “at arm’s length” and suggested he shouldn’t learn too much about their fundraising plans. OpenAI counters that those were off-hand remarks, not binding decisions. The trial, set to begin Monday in San Francisco, will hinge on whether the jury sees those exchanges as proof of bad faith or just workplace banter. At stake is more than money. A verdict for Musk could slow OpenAI’s partnerships and shake investor confidence across the A.I. sector. A win for OpenAI would be a green light for other startups to shift their governance away from founders and toward deep-pocketed backers. Either way, the result could reshape how emerging tech companies balance mission statements with fundraising demands.