OAKLAND, April 29 -- Billionaire Elon Musk took the stand Tuesday to accuse OpenAI and its boss Sam Altman of betraying the AI company's altruistic origins, in a trial that could have far-reaching consequences for the industry and oblige the ChatGPT maker to profoundly revamp its business.

The legal clash across the bay from San Francisco is widely seen as a battle of egos pitting the world's richest person against a startup Musk once backed and now trails in the booming AI sector.

At the heart of the case is Musk's accusation that Altman drove OpenAI to become a profit-seeking juggernaut looking to dethrone the likes of Google, Apple and Microsoft, and betraying its non-profit mission.

"If a verdict comes up that effectively makes it ...