![]() ![]() It communicates risk in an intuitive way – an estimate of the potential loss and the probability of it occurring. So what are the key benefits of using VaR? In pole position is its simplicity and ease of interpretation. For the purpose of this piece we’ll focus on the Historical Simulation method when assessing the usefulness of VaR and its application across various hedge fund strategies. In order to avoid going down a technical ‘rabbit hole’, the key point to remember is that each of these different VaR methodologies rely – to a greater or lesser extent – on the observations of historic data. ![]() ![]() The key difference is how the distribution of potential returns is calculated, from which a level of confidence is then applied to reach the VaR. For example, a portfolio with a 1-day VaR of $10m at a 95% confidence level indicates that one can expect under normal market conditions to lose no more than $10m over a single day, 19 times out of 20 or put another way, it is the minimum loss that should be expected the remaining 5% of the time.Īt this juncture it’s important to note that whilst this is the overarching premise of VaR, there are predominantly three calculation methodologies with differing assumptions. The calculation requires a specified timeframe over which the potential loss is being measured (typically daily for hedge funds), along with the degree of confidence to be placed on that potential loss (a confidence level of 95 or 99% is typical). The purpose of this paper is not to be a detailed analysis of the various forms of VaR and their deep inner workings, however, it is worth taking a step back to briefly remind ourselves of the key components. The notion was simple – rather than looking at various metrics across individual trading desks, what single measure of risk could indicate the maximum potential daily loss across the firm, with a high degree of confidence? In simpler terms, what is my value at risk? Under the hood Dennis Weatherstone, the bank’s Chairman at the time, instituted a report known as the ‘4:15 report’ which called for an estimate of how much the trading portfolio could lose in the next 24 hours, to be distributed each day at 4:15pm. Whilst the origins of VaR can often be traced back to early in the 20 th century, it’s widely accepted that JP Morgan were the pioneers of the risk measure in the 1990s. ![]()
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