I think it depends. If it's a really big bank, even when it's only $100 the police will probably follow up on it. But with the small competitor banks even big s

I think it depends. If it's a really big bank, even when it's only $100 the police will probably follow up on it. But with the small competitor banks even big sums like $40k will not get pursued. And you can't say $40k is not a big sum. It certainly is. As a bank one has other options besides the law, though. Lawyers, private detectives, even deals with gangs. It's not impossible to survive such things and defend against it. The only thing stopping the bank is the bank itself. Like most organisations a bank is probably barely able to achieve what it makes money with and everything else trailing off into nirvana in an unlimited amount of bureaucracy.