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.

Musk’s consortium, which includes VCs like Joe Lonsdale’s 8VC and SpaceX investor Vy Capital, is offering exactly $97.375 billion to buy out OpenAI, and says in the letter 100% of the purchase price “would be paid in cash.”