The supply of home mortgage debt outstanding started growing again during the second quarter of 2015, thanks to relatively strong growth in retained portfolios, according to an Inside Mortgage Finance analysis of new data from the Federal Reserve and other sources. The Fed reported late last week that $9.901 trillion of single-family mortgage debt was outstanding as of the end of June. That was up 0.4 percent from March and represented the biggest supply of mortgage servicing since the third quarter of 2013. The servicing market had been shrinking...[Includes two data tables]