BCZ52 The purpose of discounting future cash flows is to reflect the time value of money and the uncertainties attached to those cash flows:

(a) assets that generate cash flows soon are worth more than those generating the same cash flows later. All rational economic transactions will take account of the time value of money. The cost of not receiving a cash inflow until some date in the future is an opportunity cost that can be measured by considering what income has been lost by not investing that money for the period. The time value of money, before consideration of risk, is given by the rate of return on a risk‑free investment, such as government bonds of the same duration.

(b) the value of the future cash flows is affected by the variability (ie the risks) associated with the cash flows. Therefore, all rational economic transactions will take risk into account.

BCZ53 As a consequence IASC decided:

(a) to reject a discount rate based on a historical rate - ie the effective rate implicit when an asset was acquired. A subsequent estimate of recoverable amount has to be based on prevailing interest rates because management’s decisions about whether to keep the asset are based on prevailing economic conditions. Historical rates do not reflect prevailing economic conditions.

(b) to reject a discount rate based on a risk‑free rate, unless the future cash flows have been adjusted for all the risks specific to the asset.