Wall Street tumbled in a volatile session on Tuesday after the Federal Reserve surprised investors with a half percentage-point cut in interest rates, amplifying fears about the magnitude of the coronavirus impact on the economy. Based on the latest available data, the Dow Jones Industrial Average fell 785.91 points, or 2.94%, to 25,917.41, the S&P 500 lost 86.86 points, or 2.81%, to 3,003.37 and the Nasdaq Composite dropped 268.08 points, or 2.99%, to 8,684.09.