The issue focused on financial institutions that offer customers products or services they don't legally need. But federal law enforcement officials say illegal programs also include banks and credit unions that illegally charge legitimate borrowers fees for basic banking services.

Some criminal prosecutions have gone forward in recent years. For example, federal prosecutors charged Bank of America Corp with conspiracy to commit mail fraud and unlawful bank loan practices last year. And federal authorities accused Wells Fargo & Co of violating laws related to unfair lending practices after its employees opened millions of unauthorized accounts