It really depends on how big the bank is. If a bank is really big, like HSBC, it can't/won't be penally prosecuted in real world, so the rational choice [1] is

It really depends on how big the bank is. If a bank is really big, like HSBC, it can't/won't be penally prosecuted in real world, so the rational choice [1] is actually to keep committing crimes, and settle the ones where they're caught. On the scale of such bank, even fines which would be astronomical from the perspective of a normal citizen, are peanuts (so to speak) for a large bank. [1] = in a logical, not moral, sense.