Mnuchin ran OneWest Bank from 2009 to 2015 in a manner so ruthless to mortgage holders that he has been dubbed the "Foreclosure King" by his critics.

The robo-signing scandal involved mortgage companies having their employees falsely sign hundreds of affidavits per week attesting that they had reviewed and verified all the business records associated with a foreclosure — when in fact they never read through the material and just blindly signed off. Those records, in many cases, were prepared improperly, but the foreclosures went ahead anyway because of the fraudulent affidavits.

"Did OneWest 'robo-sign' documents relating to foreclosures and evictions?" Sen. Bob Casey, D-Penn., asked Mnuchin as a "question for the record".