The Federal Housing Finance Agencys official watchdog recommended in a report this week that the agency devise a way to measure how its guaranty fee hikes of the past two years have actually increased the participation of private investment in the mortgage-backed securities sector. As Fannie Maes and Freddie Macs conservator, the Finance Agency directed the GSEs to increase their guaranty fees as a means to encourage greater private-sector investment in mortgage credit risk, reduce their dominant position in housing finance and limit potential taxpayer losses, the FHFA Office of Inspector General report noted. The enterprises average combined guaranty fees have nearly doubled since 2011 due to legislation and FHFAs initiative and FHFA plans further gradual guaranty fee increases to spur private-sector mortgage investment, said the OIG. However, it is not yet clear how high FHFA must increase guaranty fees to achieve its objectives.