Chipmaker Qualcomm Inc QCOM.O gained 2.1% on a new $10 billion stock buyback plan. Wall Street ended lower in choppy trading on Tuesday, as investors grew jittery in the run-up to earnings amid worries about supply chain problems and higher prices affecting businesses emerging from the pandemic. "A strong inflation will only reinforce the expectation that the Fed would start tapering its bond purchases by next month, that's already priced in," said Ipek Ozkardeskaya, senior analyst at Swissquote Bank.