The euro fell to a two-month low as investors flocked to the safety of the dollar and U.S. Treasurys. Gold prices also rose.
Investors are worried that other weak European countries like Portugal and Spain will still need help even after the $90 billion bailout package for Ireland announced on Sunday.
Some of those worries faded late in the day as traders shifted their focus to positive economic news. The Federal Reserve Banks of Dallas and Chicago both reported higher manufacturing activity in their areas.
"The fundamentals are improving and there are several indications that the economy is picking up a little bit of steam here," said Peter Cardillo, chief market economist at Avalon Partners, a New York brokerage house. "There's a slew of numbers that are coming out later this week and the market is preparing for that."
The Dow Jones industrial average fell 39.51 points, or 0.4 percent, to close at 11,052.49. It had been down as many as 163 earlier.
The Standard & Poor's 500 index edged down 1.64, or 0.1 percent, to 1,187.76. The technology-heavy Nasdaq composite index dropped 9.34, or 0.4 percent, to 2,525.22.
Holiday retail sales also got off to a good start in the post-Thanksgiving weekend. The National Retail Federation, a trade group, estimated that 212 million shoppers visited stores and websites during the first weekend of the holiday season, up from 195 million last year.
Online spending rose more than 14 percent from Thanksgiving Day through Saturday, according to IBM's Coremetrics. Shares of online retailer Amazon.com rose 1.3 percent on expectations that shoppers were returning on what is known as "Cyber Monday," when retailers offer deals to lure people to buy items online while at work.
A fuller picture on spending will come Thursday when retailers report November sales. Investors have been hoping that consumers, who have generally been spending cautiously since the recession, would feel more comfortable about shopping during the holidays.
Bank stocks were some of the best performers. Wells Fargo & Co. rose 2 percent, Bank of America Corp. was up 1.7 percent, while JPMorgan Chase & Co. rose 1.7 percent.
Dick Bove, a banking analyst at Rochdale Securities, said investors realized that some U.S. banks had little exposure to European debt issues. He added that if European banks are subject to more stringent capital requirements, U.S. banks could benefit.
"When people sit down and think about the situation in Europe, it is clear that the American banks emerge in a much stronger position," he said.
In corporate news, Wal-Mart Stores Inc. rose 0.2 percent, after the company said it is buying a 51 percent stake in South African retailer Massmart. The transaction, worth about $2 billion, will cost Wal-Mart $20.71 per share. It gives the retailer access to the growing South African economy.
Oil prices rose $1.97 to $85.73 a barrel. Gold for February delivery rose $3.20, or 0.3 percent, to $1,367.50 an ounce.
The dollar rose 0.4 percent against an index of six other currencies.
Bond prices rose as investors shifted money out of riskier assets like stocks and commodities and into defensive investments. The yield on the 10-year Treasury note, which moves opposite its price, fell to 2.83 percent Monday from 2.87 percent Friday.
Investors were also cautious as they awaited the week's economic reports, including the government's monthly employment report due out on Friday. Also due this week are the Conference Board's survey of consumer confidence on Tuesday, and the Institute for Supply Management's assessments of the manufacturing and services industries.