Originations of jumbo mortgages increased in the third quarter of 2017 compared with the previous period, according to a new ranking and analysis by Inside Nonconforming Markets. But through nine months of the year, production was down compared with 2016 and the sector is losing market share as a handful of major lenders are seeing significant declines in their jumbo production. Demand for jumbo mortgages has declined somewhat, according to lenders ... [Includes one data chart]