Stocks are moving lower in midday trading, led by declines in energy and mining companies as prices for oil, metals and other commodities weaken.
Several companies were also moving lower Wednesday after reporting disappointing results or outlooks.
Nike, one of the 30 stocks in the Dow Jones industrial average, sank 4 percent after reporting revenue that fell far short of what analysts were looking for.
Software maker Red Hat gave up 5 percent after delivering disappointing forecasts.
The Dow average was down 64 points, or 0.4 percent, to 17,518 as of 11:45 a.m. Eastern time.
The Standard & Poor's 500 index lost 10 points, or 0.5 percent, to 2,039. The Nasdaq composite gave up 40 points, or 0.8 percent, to 4,781.