The Nikkei average slid 620.14 points, or 4.2 percent, to 14,309.41, its lowest level in more than six years.

The Dow industrials slid 665.27 points, or 7.7 percent, to 8,019.26.

The Standard & Poor's 500 index slid 19.75 points, to 844.61.

The Nasdaq composite index slid 55.3 points, or 3.9 percent.

The Nasdaq composite index slid 38.15 points, or 2.1 percent, to 1,758.68.

The Nasdaq composite index slid 63.11 points, or 1.6 percent, to 3,877.23.

The Nasdaq slid 13 points, to 2,166.74, for its biggest decline in a month.

Within half an hour, the Dow industrials had slid 17 points, gaining it all back by 11:30.

The Dow Jones industrial average slid 29.74 points, or just a little less than 1 percent, to 2,983.23.

In the last four trading sessions, the Dow has slid almost 110 points.