U.S. stocks fell sharply again Tuesday, The Dow Jones industrial average fell 631.56, or 2.7 percent, to 23,018.88. The broader Standard & Poor's 500 index fell 86.60, or 3.1 percent, to 2,736.56. The technology-heavy Nasdaq composite index fell 297.50, or 3.5 percent, to 8,263.23.