V@R and minimal tick value
A Value-at-Risk (VaR) methodology is a technique to estimate the maximum loss at a given time horizon that is exceeded only at a certain probability level. Several methodologies are used to obtain those estimations and a lot of them are based on “scenarios”. They can be historical data inspired, stress tests or Monte Carlo. Those methodologies are often used to compute Initial Margin (IM) related to exchange traded portfolios. The instruments in exchange trades setup have standardized terms and conditions, including a “tick value” or “minimal increment” which indicates the precision of the price quotation mechanism. This is often one cent on prices and one basis point for interest rates. I have been involved in many VaR and IM methodologies over the past years: development, replication, validation. One question that I have been asked several times with different flavours is: How should the methodology account for tick value in the scenarios? Should the price generated by the scena...