New single-family MBS issuance accounted for a record 90.1 percent of home loan originations during the first quarter of 2013, according to a new Inside MBS & ABS analysis. An estimated $500.0 billion of new home mortgages were originated during the first three months of the year, down 4.8 percent from the fourth quarter of 2012, as refinance activity began to weaken. But mortgage securitization activity declined at a slower pace, falling just 0.6 percent in the first quarter. That pushed...[Includes one data chart]