A benefactor to OpenAI's co-founders – to whom he gave $38 million from 2015 to 2017 – Elon Musk accuses CEO Sam Altman and his partner Greg Brockman of betraying the startup's charitable mission by transforming it into a commercial company valued at more than $850 billion and poised to go public.

Arguments in the trial over Elon Musk's lawsuit against OpenAI and CEO Sam Altman for becoming a for-profit company begin in California on Tuesday.

Trial is culmination of a years-long feud between Musk and Altman that has become increasingly vicious