Stocks ended their worst quarter since the depths of the 2008 credit crisis, crippled by Europe's debt debacle, a U.S. credit downgrade and a sputtering global economy.

Based on the latest available data, the Dow Jones industrial average was down 240.60 points, or 2.16 percent, at 10,913.38. The Standard & Poor's 500 Index was down 28.98 points, or 2.50 percent, at 1,131.42. The Nasdaq Composite Index was down 65.36 points, or 2.63 percent, at 2,415.40.