U.S. stocks fell sharply Thursday, The Dow Jones industrial average fell 807.77, or 2.8 percent, to 28,292.73. The broader Standard & Poor's 50 index fell 125.78, or 3.5 percent, to 3,455.06. The technology sector fell more than 6 percent. The technology-heavy Nasdaq composite index fell 598.34, or 5 percent, to 11,458.10.