Columbia U.S. Government Mortgage Fund - Mutual Funds ... Barclays U.S. Mortgage-Backed Securities Index, -, 0.26, 2.41, 4.03, 4.66, 2.80, 3.92, 4.95, -. Lipper Category: U.S. Mortgage Funds, -, 0.22, 2.15, 3.79, 4.10, 3.13 ...