i find this a good example of banking:
Graham Hodgson January 2012
Reserve ratios and capital-adequacy ratios serve separate purposes and are not interchangeable. Reserve ratios were designed to ensure that banks always had enough cash to meet customer demand for withdrawals. These requirements have largely been abandoned as regulatory constraints. Banks are free to make their own prudential provisions and make full use of inter-bank borrowing to make up any shortfall. This was considered possible because reserves form a closed pool of money held by the clearing banks, those with accounts at the Bank of England. If one bank has a shortage, another must necessarily have a surplus so there should always be money available to borrow to cover the shortage. This is the reason for the regulatory angst at banks' refusal to lend to each other. However, the Bank of England does require that the larger banks deposit securities to the value of 0.11% of their customer deposits and other short-term borrowing. These cash-ratio reserves are not available to finance the banks' operations but are intended to provide an income for the Bank of England (the revenue stream from the securities).
Capital adequacy ratios are designed to ensure that banks are able to absorb losses in the event that loans default or the market price of financial assets falls. In such events, the reported value of total assets falls and there must also be a corresponding fall, therefore, on the liabilities side, and that is the function of capital. Capital is the record of the funding made available to the bank by shareholders and bondholders, and it includes the accumulated balances of the retained earnings, provisions for bad debts and depreciation and other contingency accounts. When assets decline in value, the corresponding amount is written off against one of these capital accounts. The Basel Accords defines how banks are to calculate adequate levels of capital based on the risk that the value of their assets may prove to have been overstated.
v.positivemoney.org.uk/discussion/442/qu...irement-in-the-uk/p1