Who's paying the EUR 21bn?

Let me get this right...  The banks are paying EUR 21,000,000,000 a year for payments not going STP?

Not likely! SEPA directives are quite clear in what information a customer must provide for a SEPA payment. If there's an error in STP due to data errors, it's likely the customer is at fault, or will at least take the blame. Almost all banks, if not all, have a very nice hefty fee for exceptions that prevent a payment from going STP. You can be be darn sure that the customer is picking up the tab for these EUR 21bn worth of exceptions.

With SEPA, the banks' normal payments fee revenue is supposed to decrease, or at least that's the plan from the politicians sitting in Brussels. However we bankers have been pretty good at finding a few loopholes to that. A SEPA payment that requires exception handling gets more fees than one going STP. Now ask yourself, how do we bankers protect our fee revenues in this area? You certainly don't need me to do the math here.