Stocks edged lower on Monday after fears of a divided parliament in Italy, the euro zone's third-largest economy, rekindled worries about the currency union's stability.
The center-right coalition led by former prime minister Silvio Berlusconi was leading in the race for the Italian Senate, dashing hopes of a pro-reform, center-left victory seen as crucial to dig the euro zone out of a debt crisis.
The market had hoped for a center-left victory because it would continue the path to pay down Italian debt, said Art Hogan, managing director of Lazard Capital Markets in New York.
"What we don't want to hear is a renewed fear about a euro zone fracture," he said.
The S&P 500 was nonetheless near highs not seen in five years, and bets on a strong U.S. economy have given equities support. The S&P 500's slight fall last week was the first weekly drop after a seven-week string of gains.
Barnes & Noble Inc (BKS.N) climbed 9 percent to $14.73 after its chairman offered to buy the bookseller's declining retail business.
The Dow Jones industrial average .DJI fell 22.5 points or 0.16 percent, to 13,978.07, the S&P 500 .SPX lost 2.15 points or 0.14 percent, to 1,513.45 and the Nasdaq Composite .IXIC added 3.18 points or 0.1 percent, to 3,164.99.
The Nasdaq received support from Amgen Inc (AMGN.O), up 3.8 percent to $90.16 after a voluntary recall from a competitor to its top-selling red blood cell booster Epogen.
European shares .FTEU3 trimmed gains, edging up 0.1 percent and Italy's main FTSE MIB .FTMIB was up 0.7 percent after earlier gaining near 4 percent.
U.S. equities will face a test with the looming debate over the so-called sequestration, U.S. government budget cuts that will take effect starting Friday if lawmakers fail to reach an agreement over spending and taxes. The White House issued warnings about the harm the cuts are likely to inflict on the economy if enacted.
With 83 percent of the S&P 500 having reported results, 69 percent of beat profit expectations, compared with a 62 percent average since 1994 and 65 percent over the past four quarters, according to Thomson Reuters data.
Fourth-quarter earnings for S&P 500 companies are estimated to have risen 6 percent, according to the data, above a 1.9 percent forecast at the start of the earnings season.