There was a significant increase in deliveries to the GSEs of home loans with high debt-to-income ratios during the second half of 2017, according to a new Inside The GSEs analysis of Fannie Mae and Freddie Mac single-family mortgage-backed securities.The two GSEs securitized $52.90 billion of mortgages with DTI ratios ranging from 46 percent to 50 percent over the last six months of the year. That was up 72.6 percent from the first half of 2017, and the annual total was up 37.6 percent from 2016.