U.S. stocks ended down slightly on Tuesday as a drop in healthcare and biotech stocks offset gains in United Technologies and Verizon. The Dow Jones industrial average fell 13.43 points, or 0.08 percent, to 17,217.11. The S&P 500 index lost 2.89 points, or 0.14 percent, to 2,030.77. The Nasdaq Composite dropped 24.50 points, or 0.5 percent, to 4,880.97.
