By Myra P. Saefong
SAN FRANCISCO (MarketWatch) - U.S. stocks dropped Monday after the Institute for Supply Management reported that conditions for the nation's manufacturers fell below 50% to 49.7% in June, into contraction territory, from 53.5% in May. A MarketWatch-compiled economist poll forecast a fall to 52.3%. "The ISM number confirms a slowdown moving below the 50 point measure," said David Pankiw, partner at Cubic Financial Advisors. "The U.S. economy will follow the global economic slowdown." The Dow Jones Industrial Average DJIA -0.45% fell 59 points, or 0.5%, to 12,820. It was trading around 12,878 shortly before the data. The S&P 500 SPX -0.33% shed 4 points, or 0.3%, to 1,358, while the Nasdaq Composite COMP -0.19% lost 4 points, or 0.2%, to 2,931. Separate data on construction spending showed a stronger-than-expected 0.9% climb in May.