A consortium led by Elon Musk said it has offered $97.4 billion to buy the nonprofit firm that controls ChatGPT maker OpenAI, months after the billionaire sued the artificial intelligence startup to block it from transitioning to a for-profit firm, Reuters reported.

The bid could heighten the longstanding tension between Musk and OpenAI CEO Sam Altman over the future of the startup, which has been at the heart of the boom in generative AI technology.

Altman replied on Twitter: “no thank you but we will buy twitter for $9.74 billion if you want.”

Musk and Altman, who together helped start OpenAI in 2015 and later competed over who should lead it, have been involved in a fight over the startup’s direction since Musk resigned from its board in 2018. The two are already embroiled in an ongoing lawsuit.

“It’s time for OpenAI to return to the open-source, safety-focused force for good it once was,” said Mus. “We will make sure that happens.”

The bid is supported by Musk’s AI company xAI, which could merge with OpenAI following a deal, according to the Wall Street Journal, which first reported Musk’s offer.

The bid is also being backed by investors including Valor Equity Partners, Baron Capital, Atreides Management, Vy Capital and 8VC, a venture firm led by Palantir co-founder Joe Lonsdale, and Ari Emanuel through his investment fund.

OpenAI was valued at $157 billion in its latest funding round in October.