For most of the day, it appeared that the market had shaken off some of its worries about the slowdown in China, and at one point the Dow was up by as much as 441. But then sell orders began pouring in in the last 15 minutes of trading.
The Dow ended the day with a loss of 204.91 points, or 1.3 percent, at 15,666.44. The Standard & Poor's 500 index fell 25.59 points, or 1.4 percent, to 1,867.62. The Nasdaq composite declined 19.76 points, or 0.4 percent, to 4,506.49.