Nadella defends $135bn stake as Musk accuses OpenAI of mission betrayal Last updated: May 12, 2026 | 02:00 Microsoft CEO Satya Nadella arrives to court at the Ronald V. Dellums Federal Building on May 11, 2026 in Oakland, California. AFP Microsoft CEO Satya Nadella said Monday he was "very proud" of his company's profitable early investment in OpenAI, as he took the stand in Elon Musk's blockbuster lawsuit against the leaders of the AI giant behind ChatGPT. Musk — an early benefactor of the original nonprofit company — claims Microsoft knowingly helped OpenAI's creators betray their philanthropic mission and turn the firm into a cash cow. The trial has laid bare strife within a circle of elite Silicon Valley engineers, investors and executives in the years leading up to the high-profile launch of the ChatGPT chatbot in 2022.…