After starting 2015 with a net decline in supply of outstanding single-family mortgage securities, the market began to rally and ended the year with a modest gain. A new analysis by Inside MBS & ABS reveals that total residential MBS in the market reached $6.412 trillion at the end of last year, an 0.5 percent increase from the third quarter and up 1.0 percent from yearend 2014. The growing supply of residential MBS slightly outpaced the 0.3 percent increase in home mortgage debt outstanding, resulting in a 64.2 percent securitization rate in the fourth quarter. There are...[Includes two data tables]