The credit window for Fannie Mae and Freddie Mac single-family mortgages opened a little wider during the third quarter of 2018 as competition intensified in the primary market. A new Inside Mortgage Trends analysis of mortgage-backed securities issued by the government-sponsored enterprises during the third quarter revealed modest increases in the shares of purchase mortgages with low credit scores, although trends in loan-to-value ratios were mixed ... [Includes two data charts]