U.S. stocks plummeted again Thursday, with the three major indexes losing more than 9 percent. The Dow Jones industrial average fell 2,352, or 10 percent, to 21,200.95. The broader Standard & Poor's 500 index fell 260.75, or 9.5 percent, to 2,480.63. The technology-heavy Nasdaq composite index fell 750.25, or 9.4 percent, to 7,201.80.