US stocks dipped during a shortened Christmas Eve session Monday amid pessimism about prospects for a \"fiscal cliff\" deal by the end of the year. The Dow Jones Industrial Average was down 51.76 points (0.39 percent) at 13,139.08 in closing trade. The broad-market S&P 500 lost 3.49 points (0.24 percent) at 1,426.66, while the tech-rich Nasdaq Composite shed 8.41 points (0.28 percent) at 3,012.59. The White House and lawmakers have until the end of the year to reach a deal to avert the so-called fiscal cliff, a combination of steep tax hikes and spending cuts due to take effect in January. With the clock ticking, no compromise appears imminent.