This is credit cards. I consulted at a major credit card company many years ago. Their main system was the usual: mainframes with three money buckets one for ch

This is credit cards. I consulted at a major credit card company many years ago. Their main system was the usual: mainframes with three money buckets one for charges, one for cash advance, and other. They tried to move the whole thing to UNIX so they could ditch cobol/mainframes and so that they could have N money buckets for cross selling deals. But that software project failed.