The strong growth in issuance of jumbo mortgage-backed securities seen since 2010 stumbled in 2014, according to a new ranking and analysis by Inside Nonconforming Markets. Some $9.79 billion in jumbo MBS were issued last year, down 25.4 percent from activity in 2013. Issuance has been constrained by bank portfolio demand for jumbo mortgages. The spike in interest rates in 2013 led to nine months of very low issuance. Rates have since fallen and a number of new jumbo MBS issuers have entered the market, but quarterly volume has struggled to reach the levels seen in early 2013. Those looking for a silver lining could...[Includes one data chart]