• Liquidity and profitability
In a bank's balance sheet, the money a bank lends to its customers and other banks appears as assets because this money is a source of income and profits. The money deposited by customers appears as liabilities because this money is repayable to customers, either immediately on demand or on expiry of a notice period.
In accounting terms, liquidity is a measure of the ability of a debtor to pay their debts as they fall due. This suggests that the bank, which has effectively ‘borrowed’ the money its customers have deposited, must keep enough cash available to repay this money to customers who want to withdraw it. Yet, as a business, the bank needs to make a profit and if it were to keep enough cash available to meet all likely withdrawals, it wouldn't be able to invest it to make a profit.