Energy drags Wall St. lower; S&P set to drop for third week

U.S. stocks slumped on Friday, putting the S&P 500 on track for its third straight weekly decline, as a robust dollar threatened to erode the profits of multinationals and tumbling crude oil prices pressured energy shares. Crude oil (CLc1) fell 4 percent to $45.15 a barrel, extending its losses throughout the morning, after the International Energy Agency said a global oil glut continued to build and U.S. oil production showed no signs of slowing. The S&P energy index (.SPNY) fell 1.4 pe