The Dow Jones industrial average ended a particularly volatile day...

The Dow Jones industrial average ended a particularly volatile day with its biggest rally of the year, up 488.95 points, or 6.35%, to close at 8,191.29. The S&P 500 joined in the burst of enthusiasm, closing up 45.69 points, or 5.73%, at 843.39. The Nasdaq composite also closed in positive territory, up 60.96 points, or 4.96%, at 1,290.01. All numbers are preliminary.