T witter has said it's appointed Elon Musk to its board a day after the Tesla billionaire disclosed a 9.2pc stake in the company. The world's richest man will serve as a Class II director, with the term expiring at Twitter's 2024 annual meeting. Parag Agrawal, Twitter's chief executive, said: "He's both a passionate believer and intense critic of the service which is exactly what we need on Twitter, and in the boardroom, to make us stronger in the long-term. Welcome Elon!" Twitter shares rose 6pc in pre-market trading after closing up over 27pc on Monday.