U.S. stocks fell slightly Thursday. The Dow Jones industrial average fell 68.95, or 0.2 percent, to 30,991.52. The broader Standard & Poor's 500 index fell 14.30, or 0.4 percent, to 3,795.54. The technology-heavy Nasdaq composite index fell 16.31, or 0.1 percent, to 13,112.64.