Jeffrey Gundlach, CEO of DoubleLine Capital LP, presents during the 2019 Sohn Investment Conference in New York Reuters The so-called “bond king” Jeffrey Gundlach said in a webcast Tuesday retail investor activity is “downright terrifying.”While stimulus has helped many survive the pandemic, it has provided other amateur investors capital to invest in stock markets. Online trading platform Robinhood has added more than 3 million accounts in 2020. Day-traders have piled into several worthless stocks such as Hertz and JCPenney despite the risks. Visit Business Insider’s homepage for more stories. Hedge fund billionaire Jeffrey Gundlach is sounding the alarm on a “downright terrifying” boom in