Before trading opened, the Commerce Department reported a 0.3 percent dip in retail sales for January due to a sharp drop in auto sales — though without those sales, the retail figure would be up 0.9 percent for the month. Economists had been expecting a flat performance.

First-time unemployment claims for the first full week of February were at 363,000, more than the 345,000 expected by Wall Street and 6,000 higher than the previous week.

"What we’re seeing is a little profit-taking after what was a favorable response to the comments the Fed made," said Stuart Freeman, chief equity strategist for A.G. Edwards & Sons. "Some of the stocks that moved aggressively Wednesday were very cyclical companies, and now you’re seeing rotation back into more defensive positions."

According to preliminary calculations, the Dow Jones industrial average fell 43.63, or 0.4 percent, to 10,694.07, a day after the Dow gained 123 points on Greenspan’s economic report.

Broader stock indicators were also lower. The Standard & Poor’s 500 index was down 5.65, or 0.5 percent, at 1,152.11, and the Nasdaq composite index slid 16.06, or 0.8 percent, to 2,073.60.

Greenspan spent a second day on Capitol Hill, this time before a Senate committee. He continued the themes from yesterday’s House testimony — better-than-expected gross domestic product growth, a lowered inflation estimate for the year and a warning against mounting federal budget deficits. His outlook sent stocks sharply higher on Wednesday.

Investors were also continuing to weigh Comcast Corp.’s hostile takeover bid for The Walt Disney Co. Comcast was down $1.17 at $30.06, while Disney gained 40 cents to $28.00.

"Speaking broadly, more mergers can be a comforting indicator from an investor’s perspective," said Jack Caffrey, equities strategist at JP Morgan Private Bank. "It shows that companies are comfortable with their own operations, their own management and their own finances."

Trading of ImClone Systems Inc. was halted on the Nasdaq Stock Market this afternoon just before the Food and Drug Administration approved the company’s colon cancer drug, Erbitux. The last ImClone trade before the halt was at $34.00, down $9.10, after the stock had been trading narrowly between $42 and $44 for most of the day.

The halt, issued due to the pending news, was extended through the close of trade. The stock reopened for after-hours trading at 4:20 p.m., according to a Nasdaq spokeswoman.