They might not have "loaned" their customers money but they don't have it anyhow. Because "their customers money" is just a number in their database. Imagine a

They might not have "loaned" their customers money but they don't have it anyhow. Because "their customers money" is just a number in their database. Imagine a new bank with no money and no customers. First customer walks in "Can I loan $100?". Bank: Sure. We make an account for you. Your account number is 1. Your balance is $100. Next day the customer walks in again. "I'd like to get my $100 in cash to go shopping". Bank: "Uh oh. Sorry, we have to file for bankruptcy."