UPDATE 1-U.S.-based stock funds attract $2.8 bln over week -Lipper

(Adds analyst comment, context, table, byline) By Luciana Lopez NEW YORK, Jan 29 (Reuters) - Investors in U.S.-based funds added a net $2.8 billion into stock funds in the week ended Jan. 28, data from Thomson Reuters' Lipper service showed on Thursday. Exchange-traded funds, thought to represent the behavior of institutional investors, attracted $917 million in new cash. Mutual funds, thought to represent retail investors, added a net $1.84 billion. U.S.-based taxable bond f