"The marketplace is a little too sanguine, and expectation levels might have to be tempered going forward," said Stephen Massocca, president of Pacific Growth Equities.

The Dow Jones industrial average closed down 69.93, or 0.7 percent, at 9,721.79, for a three-day loss of 91 points.

Broader stock indicators also finished lower today. The Standard & Poor’s 500 index fell 10.75, or 1 percent, to 1,039.32, and the Nasdaq composite index declined 37.78, or 1.9 percent, to 1,912.36.

For the week, the Dow rose 0.5 percent, the Nasdaq lost 0.2 percent, and the S&P edged up 0.1 percent.

Poor earnings reports from several companies late yesterday, including Sun Microsystems Inc. and DoubleClick Inc., weighed down technology shares in trading today.

EBay Inc. reported a 69 percent surge in profits, but analysts said the online auction house’s period of rapid growth may be fading. EBay’s shares dropped $2.64 to $54.86 on the Nasdaq Stock Market.

"I think a lot of the expectations are already priced in the numbers," said Neil Massa, equity trader at John Hancock Funds. "Companies not only have to do better, they have to guide higher. ... But earnings overall have been fine, and the economic numbers point to a recovery."

Sun fell 7 cents at $3.56 in heavy trading on the Nasdaq after reporting a wider-than-expected loss. The computer maker continues to struggle with weak demand and questions about its strategy.

DoubleClick plunged $2.98 to $9.26 after the online advertising company gave an outlook for its fourth quarter performance that missed Wall Street’s estimates.

Ahold, the Dutch-based global food retailer, saw its U.S.-listed shares drop 50 cents to $9.56 after the company offered a grim outlook for its business, the first time it has discussed performance since a recent accounting scandal.

Gainers included Micron Technology Inc., which edged up 2 cents to $12.85 despite a downgrade by a UBS analyst.

The disappointing corporate news outweighed several encouraging economic indicators. The Commerce Department reported that residential construction rose in September from the previous month, climbing to the second-highest level so far this year.

The report reinforced hopes that a strong housing market, which is being fueled in part by historically low interest rates, is helping to drive the economy out of its doldrums.

A separate survey from the National Association of Home Builders found that builders were optimistic about sales prospects for October and for the next six months, yet another positive sign for the sector.