It follows then that what enables banks to create credit and hence money is their exemption from the Client Money Rules. Thanks to this exemption they are allowed to keep customer deposits on their own balance sheet. This means that depositors who deposit their money with a bank are no longer the legal owners of this money. Instead, they are just one of the general creditors of the bank whom it owes money to. It also means that the bank is able to access the records of the customer deposits held with it and invent a new ‘customer deposit’ that had not actually been paid in, but instead is a re-classified accounts payable liability of the bank arising from a loan contract.
Whether the Client Money Rules were designed for this purpose, and whether it is indeed lawful for banks to reclassify general ‘accounts payable’ items as specific liabilities defined as ‘customer deposits’, without the act of depositing having been undertaken by anyone, is a matter that requires further legal scrutiny, beyond the scope of this paper.
from: “How do banks create money, and why can other firms not do the same? An explanation for the coexistence of lending and deposit-taking ” by Richard A. Werner