The seasonal surge in primary market mortgage originations stood in stark contrast to a slump in new residential MBS issuance during the second quarter of 2017. Mortgage lenders originated an estimated $455.0 billion of new first-lien loans during the April-June cycle, an 18.2 percent increase from the first three months of the year, according to estimates by Inside Mortgage Finance. But the secondary market generated just $294.7 billion in MBS backed by purchase and refinance loans – a 5.3 percent decline. The result was...[Includes one data table]