Tesla boss Elon Musk said on Monday he will serve as chief executive of Twitter, the social media company he just bought for $44 billion, a move that Wall Street analysts have said could stretch the billionaire thin.

Musk, who also runs rocket company SpaceX, brain-chip startup Neuralink and tunneling firm the Boring Company, fired Twitter's previous chief, Parag Agrawal, and other top company officials last week, and has proposed revisions to the platform's user verification process that has been free until now.

Responding to a tweet from author Stephen King that he would not be willing to pay $20 a month to keep the verified badge on Twitter, Musk replied: "How about $8?"