A bank is absolutely free to create the loan from nothing apart from your promise to pay it back. Loans are 'backed' by capital (paid up shares, retained earni

A bank is absolutely free to create the loan from nothing apart from your promise to pay it back. Loans are 'backed' by capital (paid up shares, retained earnings, etc). They have to have enough capital to cover at least 8% of the amount of the money they have created by lending with the recent Basel 3 rules. What the bank is doing is managing IOUs. You do not store money in the bank, and the bank does not loan stored money. When you deposit money in the bank, they take it and give you an IOU (bank credit). When you loan from the bank, you make an IOU to them (loan), and they give you an IOU (a new deposit in bank credit). When you make a withdrawal, you're exchanging one of those IOUs (credit) to cash. When you make a transfer, they reduce their IOU to you, and then either increase an IOU to someone else, or settle that transaction between banks with some asset (such as bank reserves). The bank does hold some of their assets at the central bank of their country (or ECB for Eurozone banks). But they actually try to keep as little as possible in there, and they don't need that much compared to the amount of bank credit on the bank's balance sheet.