Purchase-mortgage lending has become increasingly critical to maintaining production volume throughout the year, and there are some indicators that lenders may be starting to stretch a little more to bring in new business, according to a new Inside Mortgage Finance analysis of Fannie Mae and Freddie Mac loan-level data. During September, purchase mortgages accounted for 42.4 percent of new business at the government-sponsored enterprises and may well surpass refinance volume by the end of the year. As recently as March 2013, purchase mortgages represented just 16.3 percent of single-family loans securitized by the two GSEs. After monthly activity peaked at $36.9 billion in August, the actual volume of purchase mortgages delivered to the GSEs did sputter...[Includes two data charts]