Market share for lenders whose loans were included in prime jumbo mortgage-backed securities was much more dispersed in 2017 than the previous year, according to a new ranking and analysis by Inside Nonconforming Markets. JPMorgan Chase – the top issuer of jumbo MBS – remained the lender with the most collateral for new deals. But the bank reduced its jumbo deliveries by a whopping 65.1 percent from 2016 to just $1.58 billion last year. That was still tops in the market, accounting for 14.5 percent of the loans pooled in $10.88 billion of ... [Includes two data charts]