A measure of the potential loss in value of a specified asset or portfolio of assets over a defined period for a given confidence interval. For example, if the VaR on an asset is £10 million for a one-week 95 per cent confidence level, then there is a probability of 5 per cent that the value of the asset will fall by more than £10 million in any given week. VaR is used by banks to measure the potential loss in value of their portfolios. The loss can then be compared to available capital and cash reserves to assess the risk position of the bank.