The chief executive of ChatGPT-owner OpenAI says it is "not for sale" after a $97.4bn (£78.4bn) takeover bid from a consortium of investors led by Elon Musk.

Sam Altman, who co-founded OpenAI with Musk before a public falling out led to Musk's departure, was speaking at the AI Action Summit in Paris.

"We are an unusual organisation and we have this mission of making AGI (artificial general intelligence) benefit all of humanity, and we are here to do that," Altman said in an on-stage interview.

When asked to define AGI, Altman said "Most people use it to mean, like, really strong, powerful AI systems".

Musk's attorney, Marc Toberoff, confirmed he had submitted the bid for all OpenAI's assets to its board on Monday.

Earlier, in response to the move, Altman posted on Musk's social media platform X: "no thank you but we will buy Twitter for $9.74 billion if you want".

Who owns OpenAI?

Unlike many tech giants, such as Meta or Microsoft, OpenAI is not a publicly traded company.

Instead, it has a complicated structure with involves a partnership between non-profit and for-profit arms.

Musk says he wants to return it to its non-profit roots and original mission of developing AI for the benefit of humanity.

However, Musk also owns a rival firm, xAI.

Christie Pitts, a tech investor in San Francisco, told the BBC she was sceptical about Musk's motives.

"I think it's fair to be pretty suspicious of this considering that he has a competitor himself... which is structured as a for-profit company, so I think there's more than meets the eye here," she said.

Altman has suggested something similar telling Axios Musk was "a competitor who is not able to beat us in the market and you know, instead is just trying to say, like, 'I'm gonna buy this' with total disregard for the mission".

Altman is chief executive of OpenAI and sits on the board of the nonprofit.

He said in May last year that he does not own any stock in the organisation.

Altman wants to transform the organisation into a fully for-profit company, which he says will allow it to raise more money to put into AI research.

However, the decision over OpenAI's future is not Altman's alone - the board will have a say on the company's future and may favour a sale, especially if the offer is increased.

The offer tabled at $97.4bn is much lower than the $157bn OpenAI was valued at in its latest funding round in October last year. Talks over a further funding round reportedly value it now at $300bn.

In a statement, Mr Toberoff said the consortium would be "prepared to consider matching or exceeding" any potential higher bid.

"As the co-founder of OpenAI and the most innovative and successful tech industry leader in history, Musk is the person best positioned to protect and grow OpenAI's technology," Musk's attorney added on his behalf and other investors.

The creator of ChatGPT is also teaming up with another US tech giant, Oracle, along with a Japanese investment firm and an Emirati sovereign wealth fund to build $500bn of artificial intelligence infrastructure in the US.

The new company, called The Stargate Project, was announced at the White House by President Donald Trump who billed it as "the largest AI infrastructure project by far in history" and said it would help keep "the future of technology" in the US.

Musk, despite being a top advisor to Trump, has claimed the venture does not "actually have the money" it has pledged to invest, though he has also not provided any details or substantiation for the comments.