Commercial banks and savings institutions boosted their holdings of residential MBS substantially during the third quarter, a new analysis of call-report data by Inside MBS & ABS reveals. Banks and thrifts held a record $1.732 trillion of residential MBS in their available-for-sale and held-to-maturity accounts at the end of September, a 2.9 percent increase from June, not including $46.3 billion in trading accounts. The emphasis was heavily on agency pass-through securities, with holdings of Fannie Mae and Freddie Mac MBS surging 6.6 percent higher. Ginnie Mae saw...[Includes two data tables]