The billionaire warned employees of his Elliott Management hedge fund two months ago that they should prepare for a monthlong quarantine — well before New York mandated a lockdown, Bloomberg’s Katia Porzecanski reported. Mr. Singer sent an internal memo on Feb. 1 that employees in the firm’s offices around the world should “try to make arrangements so that you do not have to leave your home for a month if that becomes necessary.” (The Elliott founder is known for being cautious about anything that could affect the markets, including solar storms.)