Originations of purchase mortgages declined in the fourth quarter of 2013, and applications for purchase mortgages have been tepid in early 2014. While tight underwriting requirements could have played a role in the downward trend, industry analysts suggest that a number of other factors are also suppressing originations of purchase mortgages. Loan-level data on agency mortgages show a decline in underwriting standards for purchase mortgages during 2013, including an increase in average debt-to-income ratios and a decrease in average credit scores. The looser underwriting wasn’t enough to stave off declines in originations. Mark Fleming, chief economist at CoreLogic, said originations of purchase mortgages have been constrained in part by a lack of supply, not of loans, but of homes...