The Basle Committee’s standards require that
banks use a ten-day holding period – thus requiring banks to apply ten-day price
movements to their portfolios. The confidence level defines the proportion of trading
losses that are covered by the VaR amount. For example, if a bank calculates its
VaR assuming a one-day holding period and a 99 per cent confidence interval then
it is to be expected that, on average, trading losses will exceed the VaR figure on
one occasion in one hundred trading days.