Elon Musk, the world's richest person, took the stand and testified over the course of three days in his trial against OpenAI CEO Sam Altman.

Elon Musk sued OpenAI, Sam Altman and Greg Brockman in 2024, claiming they reneged on their promise to keep the artificial intelligence lab a nonprofit.

Altman faces off against Musk, his OpenAI co-founder, in second day of high-stakes lawsuit