New issuance of single-family mortgage-backed securities by Fannie Mae and Freddie Mac fell 30.6 percent from January to February as the refinance business continued to weaken.The two GSEs issued a combined $63.67 billion of single-family MBS last month, according to a new Inside The GSEs analysis and ranking. Absent a heavy refi flow, February is typically the low point in the annual cycle. A year ago, combined Fannie/Freddie production totaled just $50.05 billion in February. Production in the first two months of 2017 was up 45.7 percent from the same period last year, with big gains in both purchase (up 42.7 percent) and refi business (up 57.7 percent). But while purchase-mortgage lending is...