Bret Taylor, the chairman of OpenAI’s board, said the artificial intelligence company was “not for sale.” Mr. Musk is separately raising money for his A.I. start-up, xAI.

Sam Altman is leaving no room for doubt about his views on an Elon Musk-led bid to take control of OpenAI. In a letter to OpenAI staff Monday, the CEO put the words “bid” and “deal” in scare quotes and said the startup’s board has no interest in the offer.

Musk's bid is likely to ratchet up longstanding tensions with OpenAI CEO Sam Altman over the future of the startup at the heart of a boom in generative AI technology