Copper surged by the most in more than 16 years, after a wave of buying from Chinese investors triggered one of the most dramatic moves in the market’s history. Prices gained as much as 11% to trade above $14,500 a ton for the first time ever, before a sharp retracement on Thursday afternoon as the dollar jumped. Most Read from Bloomberg The industrial metal, which is used in almost every electrical application, has risen about 21% since the start of December, firing up copper bulls who have long been ...