The non-banks’ growth has been breathtaking. At the end of 2016, such unaffiliated mortgage companies accounted for more than 40 percent of new conventional mortgages (those eligible for sale to government-controlled guarantors Fannie Mae and Freddie Mac), twice the share they accounted for just eight years earlier. They’re also responsible for a decline in credit standards: The average FICO score at origination stood at 730 at the end of 2017, down from 750 five years earlier. For loans guaranteed by the Federal Housing Administration — an area where the non-banks’ share is greatest — the average FICO score has fallen to 680.