Real estate investment trusts that focus on investing in MBS held a combined $306.3 billion of mortgage securities in portfolio at the end of the third quarter, according to a new Inside MBS & ABS analysis. That total was down 6.4 percent from the end of June, as the industry has lost nearly all of the huge volume of MBS that were acquired in early 2012. At the end of 2011, REITs held $297.5 billion of MBS and over the next six months grew their combined portfolio by $76.7 billion, reaching a record $375.2 billion at the midway point in 2012. It’s been...[Includes one data chart]