Bank and thrift holdings of first-lien mortgages took a relatively rare decline in the first quarter of 2017 as jumbo production stalled during the period, according to a new ranking and analysis by Inside Nonconforming Markets. Banks and thrifts held a total of $1.93 trillion of first-lien residential mortgages in portfolio as of the end of March, down 0.1 percent from December 2016. The holdings have increased relatively steadily in recent years ... [Includes one data chart]