OpenAI's co-founder Ilya Sutskever and more than 500 other employees have threatened to quit the embattled company after its board dramatically fired CEO Sam Altman. In an open letter to the company's board, which voted to oust Altman on Friday, the group said it is obvious 'that you are incapable of overseeing OpenAI'. Sutskever is a member of the board and backed the decision to fire Altman, before tweeting his 'regret' on Monday and adding his name to the letter. Employees who signed the letter said that if the board does not step down, they 'may choose to resign' en masse and join 'the newly announced Microsoft subsidiary run by Sam Altman'.