A simple explanation of how money moves around the banking system (2013)
>First, we need to acknowledge that SWIFT is not cheap. If Barclays had to send a SWIFT message to HSBC every time you wanted to pay £10 to Charlie, you would soon notice some hefty charges on your statement.<p>Why is this so? Sure in decades past it might have been expensive to send so many messages, but today it should be easily accomplished with moderate hardware. Wikipedia says SWIFT did about 15M tx/day in Sept 2010. That seems pretty miniscule as far as hardware load goes.