The market fell on a late-morning report that a French railway worker had found a bomb under a passenger line between Paris and Basel, Switzerland, but prices recovered when it became clear that authorities had defused the device. Yet buyers remained scarce, and only the technology-heavy Nasdaq composite index, buoyed by a lift in semiconductor stocks, was able to stay in positive ground.

"I think the market is trying to price in terrorism right now," said Brian Williamson, an equity trader at the Boston Company Asset Management. "That has really been adding into the sell pressure that we’ve seen in the last few sessions."

According to preliminary calculations, the Dow Jones industrial average lost 15.41, or 0.2 percent, to close at 10,048.23, after drifting in and out of positive territory for much of the day.

Broader stock indicators were mixed. The Standard & Poor’s 500 index shed 2.62, or 0.2 percent, to 1,091.33. The Nasdaq added 7.68, or 0.4 percent, to 1,909.48.

The European Union fined Microsoft $613 million for abusing its "near monopoly" on the Windows operating system by bundling other software with it in an attempt to thwart competitors. The company also must provide European users with a version of the software without its digital media player, and release its closely guarded code to rivals in the office server market so their products can work more smoothly with Windows.

Microsoft plans to appeal the decision. Its shares advanced 26 cents to $24.41, as some investors welcomed an end to the uncertainty surrounding the case.

Investors were also pleased with an upbeat report from the Commerce Department, which said orders for durable goods rose 2.5 percent last month, more than double what economists expected. The reading far outpaced January’s 2.7 percent decline.

AT&T Corp. said it plans to increase voice-over-Internet technology offerings for businesses. AT&T rose 5 cents to $19.42.