There's a sort of prisoner's dilemma here, where the banks that don't take the 80% now make out better in both cases - they get 100% now and 100% later, or 100%

There's a sort of prisoner's dilemma here, where the banks that don't take the 80% now make out better in both cases - they get 100% now and 100% later, or 100% now and 120% later, versus 80% now and 120% later.