Banks and thrifts added some $67.2 billion in residential MBS to their investment portfolios during the first quarter of 2012, according to a new Inside MBS & ABS ranking and analysis. The increase amounted to a 4.3 percent gain from bank and thrift MBS holdings at the end of 2011, and raised the industry’s total investment to a record $1.634 trillion. It marked the first time since 2004 that banks and thrifts owned more than a quarter of the MBS market. The biggest increase was in holdings of agency pass-through securities, which rose 6.2 percent from the fourth quarter to $974.4...(Includes two data charts)