Elon Musk took the stand this week in his lawsuit against OpenAI, arguing that Sam Altman violated the company's nonprofit charter by converting it to a for-profit structure. Court filings reveal emails, texts, and tweets that Musk plans to use as evidence of betrayal.

Musk, a cofounder of OpenAI in 2015, alleges that Altman broke the original mission to develop artificial intelligence for humanity's benefit rather than shareholder returns. The lawsuit centers on whether a nonprofit can legally transition to a for-profit without breaching its founding obligations to donors and stakeholders.

The case marks a rare public split between two of tech's most prominent figures. Multiple witnesses remain on the docket, signaling this dispute will play out fully in court rather than settling quietly.

OpenAI's pivot to for-profit status happened as the company scaled rapidly, securing billions in funding from investors like Microsoft. Musk left the board in 2018 but maintained public interest in the company's direction. His lawsuit challenges whether transforming governance structures invalidates founding commitments, a question that extends beyond OpenAI to other nonprofits considering similar shifts.