The market fluctuated for much of the day before turning lower in the final hours of trading, although some retailers, semiconductor issues and communications firms saw gains. Given relatively good news, Wall Street’s inability to advance after three days of declines was discouraging, said Richard Dickson, senior market strategist at Lowry’s Research Reports in Palm Beach, Fla.

"We’re struggling to make gains, and that could mean that we are looking at perhaps the most significant pullback since the market started to rally back in March. That’s the potential," Dickson said. "The market has been growing more vulnerable to bad news, and that becomes more obvious as it’s unable to rally on good news."

According to preliminary calculations, the Dow Jones industrial average closed down 86.67, or 0.9 percent, at 9,624.16, for a four-day loss of 224.67. Terrorism fears contributed to market losses around the world yesterday.

The broader gauges also closed lower today.

The Nasdaq composite index ended down 27.86, or 1.5 percent, at 1,881.75. The Standard & Poor’s 500 index lost 9.48, or 0.9 percent, to end the day at 1,034.15.

In Washington, the Labor Department reported consumer prices were flat in October as falling costs of gasoline and other energy products canceled out the biggest jump in beef and veal prices in 24 years.

The Consumer Price Index, the government’s most closely watched inflation barometer, showed overall prices eased in October, following four consecutive months of increases. Economists were expecting a tiny 0.1 percent increase in overall prices.

Some analysts said the markets were taking a natural pause ahead of the lighter-volume days associated with next week’s Thanksgiving holiday. Investors may simply be stepping back to take some profits, said Jay Suskind, head trader at Ryan Beck & Co.

"I’m not alarmed, I think it’s rather healthy," Suskind said. "It’s an organized selloff in that there’s no sense of panic. Hopefully this will build a new base so the market can rally before the end of the year."

Among today’s advancers, General Electric gained 63 cents to close at $28.44 after Merrill Lynch upgraded it to a "buy" from a "neutral," and set a $33 price target, citing a shift toward higher-growth, higher-return businesses.

But Home Depot closed down 52 cents at $34.95, despite beating Wall Street expectations with a 22 percent jump in third-quarter earnings.

Saks Inc. shed 21 cents to close at $14.79, even though it reported earnings well above expectations.