Stocks ended Tuesday modestly lower after another steep decline in crude prices and as a sudden drop in IBM (IBM) shares pressured the Dow. Trading was also choppy ahead of Wednesday's Fed announcement. Rite Aid (RAD) rocketed higher on reports Walgreens Boots Alliance (WBA) is considering an acquisition. A deal would see the second- and third-largest U.S. drugstore chains combine. IBM fell on news the SEC was conducting an investigation into revenue recognition. The hardware giant said it would fully cooperate with the agency. Starwood Hotels (HOT) spiked on reports at least three Chinese companies are exploring a potential bid. Any deal could be the largest Chinese purchase of a U.S. company.