Pope Saint Callistus began as a slave who formed a bank with his Christian master's charity fund - donations to be given to poor widows. One day it was discovered that all the money was gone, and Callistus immediately fled Rome. Legend says that he was identified in Portus but that he jumped overboard the ship in order to escape. He was captured and brought back to Rome. Soon after he was imprisoned for fighting with Jews at a Synagogue - apparently over money lost through bad loans.
Taylor Marshall calls him the patron saint of "compromised financial services." That's an understatement.
He should be invoked for banks and other financial institutions seeking bailouts. And people who can't balance the books in general.