NEW YORK (MarketWatch) -- U.S. stocks opened modestly lower on Monday after Moody's Investors Service said the nation's credit risk had grown. The Dow Jones Industrial Average /quotes/comstock/10w!i:dji/delayed (INDU 10,615, -9.29, -0.09%) fell 8.61 points to 10,616.08. The S&P 500 Index /quotes/comstock/21z!i1:in\x (SPX 1,147, -2.76, -0.24%) dipped 3.45 points to 1,146.54. The Nasdaq Composite Index /quotes/comstock/10y!i:comp (COMP 2,361, -6.22, -0.26%) shed 7.27 points to 2,360.39