(Reuters) -OpenAI, the artificial intelligence startup behind ChatGPT, is talking to investors on a possible sale of existing shares, according to two sources familiar with the matter.

The deal could value Microsoft-backed OpenAI at between $80 billion to $90 billion, according to the Wall Street Journal, which first reported on the potential share sale.

In a sale of existing shares no new capital is raised, but insiders and investors are allowed to sell their shares.

The deal, which would make OpenAI one of the most valuable private companies in the world according to the WSJ report, also underscores the surging enthusiasm for AI startups after the launch of ChatGPT last year.

ChatGPT, a chatbot that can generate human-like responses based on user prompts, has helped AI's popularity erupt. The AI space has been hailed as the next frontier for technology and has become the latest buzzword in Silicon Valley.

Several other startups such as Inflection and Anthropic have raised funds from marquee investors in recent months.

OpenAI's new valuation would be almost triple of what the company was worth after a share sale earlier this year, the WSJ reported.

OpenAI did not immediately respond to a Reuters' request for comment.

(Reporting by Krystal Hu in San Francisco and Niket Nishant in Bengaluru; Editing by Shounak Dasgupta)