The retained mortgage investment portfolios of Fannie Mae and Freddie Mac have been reliable generators of net income over the past few years, but the government-sponsored enterprises continue to shrink the profit centers under the terms of their federal bailout. Fannie and Freddie held a combined $1.310 trillion in mortgage-related investments at the end of the first quarter of 2012, down 3.8 percent from the previous quarter. The GSEs’ combined portfolios were down 9.6 percent from the same period in 2011; their agreements with the Treasury Department call for annual...(Includes one data chart)