U.S. Markets closed in the red Tuesday after giving up small gains in midday trading. The Dow Jones Industrial dropped 100 points as investors weighed stronger-than-expected economic reports and a slight rebound in the U.S. dollar. Crude oil settled slightly higher, gaining $0.06 at $47.51 a barrel. Despite the modest rise in oil prices, Chevron (CVX) was still the worst performing blue chip in the session. But Chesapeake Energy (CHK) managed to gain on activist investor Carl Icahn adding his stake in the company to nearly 11% from around 10%. Twitter (TWTR) shares soared more than 6% on heavy volume. The social microblogging site is testing video feeds that play automatically. Amazon (AMZN) says the FAA approved the wrong drone last week to test-fly in the U.S. The e-commerce giant argued the government is too slow when it finally gave permission to a delivery aircraft that was already obsolete.