Excess Kurtosis

Excess kurtosis is a metric that quantifies how much more peaked or flat a distribution is compared to a normal distribution. A value of zero represents a normal distribution, while positive values indicate a leptokurtic distribution with fatter tails.

In quantitative finance, calculating excess kurtosis is essential for determining the risk of extreme deviations from the mean. High excess kurtosis suggests that the asset is prone to sudden, violent price swings that can liquidate over-leveraged positions.

Traders use this to refine their value-at-risk models, ensuring that they are not underestimating the probability of ruin. It acts as a direct warning signal that the market is behaving in a non-linear, unpredictable fashion that defies standard statistical assumptions.