Banks will pursue these funds and call in collection agencies but in the end the majority will write-off the debt without understanding the root cause of the fraudulent loss. In many case banks don't even know about the problem so they don't have an incentive to fix the loss, ... Perhaps it's cynical to say this but banks would rather let people in and deal with fraudulent losses, which they pass on to retailers and customers anyway. There are many dedicated people in bank anti-fraud departments but institutionally they are not that motivated.