Business was booming at Fannie Mae and Freddie Mac during the just-completed fourth quarter of 2011, with total single-family mortgage securitization jumping 47.4 percent from the previous period, according to a new analysis and ranking by Inside Mortgage Finance. The two government-sponsored enterprises pumped out a combined $261.2 billion in single-family mortgage-backed securities during the final three months of the year. That was the highest quarterly production level of the year, but it still came up 21.2 percent short of the volume generated....(Includes three data charts)