Impairment and revaluation are terms closely related to one another, with subtle
differences. Revaluation and impairment both require the company to evaluate the
assets for their fair value, and then take appropriate action in updating the
accounting books. The major difference between the two is that a revaluation can be
made upwards (to increase the value of the asset to market value) or downwards (to
decrease the value). An impairment, on the other hand, only refers to one of the two;
a fall in the market value which is then written down.