The jumbo mortgage-backed security market was dormant for over two months, but within the past 14 days, Credit Suisse issued a $287.42 million deal and JPMorgan Chase started shopping a $356.39 million issuance. Thats not to say the jumbo MBS market is back to full strength. The two deals have some unique characteristics, and banks still maintain their dominance over nonbank aggregators of jumbos. Officials at American Capital Mortgage Investment said jumbo MBS issuance has plenty of potential ...