A time-honoured convention in accounting has been that accounts should be based on the principle of historic cost, namely that all items should be recorded in terms of the purchasing power of the pound at the date of each transaction. This convention has the virtue that the accounts are based largely on factual monetary transactions and fewer items need be determined subjectively. It is a valid convention so long as the value of money remains constant, but in a period of inflation, accounts drawn up on this basis become distorted, and the higher the rate of inflation the greater the distortion. For example, amounts based on historic cost which are set aside for depreciation of plant and machinery will, in a period of rapid inflation, be totally inadequate either to provide funds for the eventual replacement of those assets or to maintain the real value of the shareholders' original capital investment. Similarly profits are overstated by the inclusion of profits on stock which arise solely from a general increase in price levels. Again, no account is taken of the real cost of holding cash or other monetary assets when money is losing its purchasing power. Conversely, no credit is taken for the gain derived from having borrowed money, when the liability for repayment of the loan is in real terms reduced.
RATIONALITY: A CENTRAL POINT BETWEEN TRADITIONAL FINANCE AND BEHAVIOURAL FINANCE