Wall Street gave King Digital, the company behind the popular mobile game "Candy Crush Saga," the cold shoulder in its public trading debut. King priced its stock at $22.50 on Tuesday, valuing the company at $7.1 billion. But it opened Wednesday at $20.50 and closed down more than 15 percent at $19. King had $1.88 billion in revenue last year. That's more than 10 times its 2012 revenue of $164.4 million.