Broad selling in tech stocks pulled US markets lower Wednesday, cutting short a six-day streak of gains by the S&P 500. Boeing, Dow Chemical and Delta Air Lines registered strong gains on better than expected quarterly reports, but their impact was offset by poor performances from AT&T and biotech giant Amgen. At the closing bell the Dow Jones Industrial Average was down 11.82 points (0.07 percent) at 16,502.55. The S&P 500 fell 4.14 (0.22 percent) to 1,875.41, while the Nasdaq Composite lost 34.49 (0.83 percent) at 4,126.97.