The Dow Jones industrial average ended up 52 points following a report that European leaders are considering more aggressive programs to bail out weaker countries in the region.
Broader market indicators were mixed. The S&P 500 index rose 1 point and the Nasdaq composite edged lower. Materials and health care companies rose the most. Agricultural supplies company Monsanto Co. rose 2.8 percent and drug maker Pfizer Inc. rose 2 percent.
Stocks were stuck in neutral for most of the day after S&P said it might downgrade the AAA rating of Europe's bailout fund. A report in the Financial Times late in the afternoon sent the Dow up as many as 117 points. The newspaper reported that European leaders are considering making more financial aid available to struggling countries.
Investors remain cautious ahead of a summit of European leaders Thursday and Friday where the main task will be coming up with credible plans for preventing a simmering debt crisis from causing a breakup of the euro, the currency shared by 17 European nations.
"We are coming to a head in Europe, and it's no longer about the small countries like Greece," said Paul Zemsky, chief investment officer at ING Investment Management. He said current stock prices reflect traders' expectations of a rate cut from the European Central Bank on Thursday and strong political action on Friday. Any less that, he said, and "it's anyone's guess show bad things will get, but they'll get pretty bad."
The Dow Jones industrial average closed up 52.3 points, or 0.43 percent, at 12,150.13. Among its top performers was 3M Co., which rose 1.5 percent after the maker of Post-It notes forecast 2012 earnings that were stronger that many analysts expected.
The Standard & Poor's 500 index closed up 1.4 points, or 0.1 percent, to 1,258.5. The Nasdaq composite average closed down 6.2, or 0.23 percent, at 2,649.56.
U.S. stock indexes have risen sharply from the lows they hit during a Thanksgiving-week drubbing. The S&P 500 is up 8.6 percent since Nov. 25, when it closed at 1,158.67.
Late Monday S&P said it might downgrade the debt of 15 countries that use the euro. The announcement, and S&P's followup statement Tuesday about possibly downgrading the European bailout fund, halted a rally in European markets.
The impact on the market was muted, said Robert Tipp, chief investment strategist with Prudential Fixed Income, because investors are coming around to the view that the European debt crisis may be through its worst phase.
"There's going to be volatility going forward, and it's going to be difficult for countries to follow their commitments, but I think you finally crossed that point where they took enough steps that the markets will get the message" that there is a credible crisis-rescue plan in the works, Tipp said.
In corporate news:
— Homebuilder Toll Brothers Inc. rose 2.7 percent after it reported fiscal fourth-quarter earnings that beat analysts' expectations.
— Alpha Natural Resources Inc. fell 1.1 percent after the company agreed to pay more than $200 million to avoid being sued over a 2010 mine disaster that killed 29 men.
— Darden Restaurants Inc. fell 12.4 percent, the most in the S&P 500 index, after the company slashed its profit forecast for 2012. The company is trying to turn around its struggling Olive Garden restaurant chain and cope with rapidly rising food costs.