Commercial banks and savings institutions reported a modest decline in their aggregate investment in residential MBS during the fourth quarter of 2012, according to a new Inside MBS & ABS analysis of call report data. Banks and thrifts held $1.579 trillion of residential MBS at the end of last year, down 2.4 percent from the close of the third quarter. It was the industry’s lowest aggregate position since the end of 2011, but banks still held an historically high 25.0 percent of total MBS outstanding. Compared to the end of 2011, bank MBS holdings were...[Includes two data charts]