That's according to sources familiar with the matter, who told Reuters exclusively that the investors are working with legal advisers to study their options.

Altman's abrupt firing by the board of directors has triggered the threat of a mass exodus of OpenAI employees.

Investors worry that they could lose hundreds of millions of dollars they invested in OpenAI with the potential collapse of the hottest startup in the rapidly growing generative artificial intelligence sector.

OpenAI did not respond to a request for comment.

The board fired Altman on Friday after what an internal memo called a "breakdown of communications."

By Monday, most of OpenAI's more than 700 employees threatened to resign unless the company replaced the board.

Reuters spoke with legal experts who said the structure of OpenAI would make it hard for investors to win a lawsuit against the board.

Because OpenAI is controlled by a nonprofit parent company, experts said that gives the board a lot of leeway when it comes to leadership decisions.

Also, OpenAI used a limited liability company as its operating arm which makes it even harder to sue directors, according to one expert.