UPS AND DOWNS: Stocks plunged at the opening of trading but recovered by midday. A rout overseas and in the early going on Wall Street was set off by a slowdown in China and worries that the Federal Reserve might slow down its bond purchases. By the afternoon the U.S. market had recouped nearly all of its loss.

BUCKING THE TREND: Hewlett-Packard surged $3.63, or 17.1 percent, to $24.86 after the company delivered second-quarter earnings that topped the estimates of both its own management and financial analysts.

BY THE NUMBERS: The Dow Jones industrial average ended the day down 12.67 points, or 0.1 percent, to 15,294.50. It fell as much as 127 points during the first hour of trading.