Stocks posted a weak start to 2014 on Thursday, as investors were cautious amid worries about slowing economic growth in China. It was the first time the three major stock markets began the year negatively since 2008. Data showed that China's factories lost some momentum in December, adding to concerns the world's second-largest economy may slow this year. In U.S. economic news, construction spending rose in November to near a 5-year high, manufacturing activity slowed but still expanded for the seventh consecutive month, and jobless claims declined for the second week. The U.S. dollar rose versus the euro and fell versus the yen. Benchmark light sweet crude futures were little changed near $98.50 a barrel on the New York Mercantile Exchange. Gold futures fell slightly to around $1,222 an ounce. The Dow Jones industrial average fell 135.31, or 0.8 percent, to 16,441.35. Twenty-seven of the index's 30 components fell, led by DuPont, General Electric, and Coca-Cola, which each fell between 1.9 and 1.6 percent. The broader Standard & Poor's 500 index fell 16.38, or 0.9 percent, to 1,831.98. The technology-heavy Nasdaq composite index fell 32.52, or 0.8 percent, to 4,143.07. Shares of Apple fell 1.4 percent after the iPhone maker's stock was downgraded by an analyst.