Wells Fargo's huge increase in mortgage-banking income accounted for nearly all the gain reported by 19 publicly traded banks. Still, the second and third quarters of 2020 were incredibly lucrative for mortgage banking platforms. (Includes data chart.)

While AmeriHome, Caliber Home Loans and Guild Mortgage have noted strong profits and plans for growth, their business strategies differ widely.

The holding company of Fulton Bank was hit with a $1.5 million fine by the SEC for misleading disclosures regarding MSR valuations in 2016 and 2017.