A risk measure used to calculate the maximum loss a financial instrument, or portfolio, is expected to suffer over a defined period with a specific confidence level. For example, a 95% 10-day VaR of $5 million means that, with 95% confidence (i.e., 95 times out of 100), the portfolio will not lose more than $5 million over a 10-day period, assuming that the portfolio composition remains the same.