Wal-Mart's comparable sales hurt by falling food prices

By Nandita Bose CHICAGO (Reuters) - Wal-Mart Stores Inc on Thursday reported lower-than-expected quarterly sales at established U.S. stores, hurt by declining food prices and unseasonably warm weather, and its shares fell nearly 3 percent. Investors shrugged off earnings that slightly exceeded analysts' estimates. Wal-Mart, the world's largest retailer, also raised the low end of its fiscal-year profit forecast, in line with Target Corp and other rivals that expressed optimism ahead of the holid