Biotech, Commodities Lead Dow Retreat
New York — U.S. stocks fell Friday, with the Dow Jones industrial average posting its worst week since January, as biotechnology shares slumped and raw-material producers sank amid fresh signs of a slowdown in China. Biogen lost 22 percent after cutting its 2015 earnings forecast. Raw-material and energy shares in the Standard & Poor’s 500 index fell at least 1.9 percent. Amazon surged 9.8 percent, while Visa Inc. gained 4.3...
