Tail Risk
Tail risk is the risk of extreme events occurring at the edges (tails) of return distributions — low probability but high impact outcomes.
Concept map
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Definition
Tail risk is the risk of extreme events occurring at the edges (tails) of return distributions — low probability but high impact outcomes.
Use case
Used in risk management workflows, analysis, and technical interviews.
Judgment check
Useful only when the assumptions and inputs behind the metric are understood.
Deep dive
How to think about Tail Risk
Normal distribution models underestimate tail risk (fat tails or leptokurtosis). Left tail events include market crashes, black swans, and contagion. Traditional VaR models often fail in crises as correlations spike to 1. Tail risk hedging uses options, volatility strategies, or alternative assets for protection.
Example: October 1987 crash: S&P 500 fell 20% in one day — a 20-sigma event under normal distribution (should occur once every trillion+ years). Yet it happened. Option strategies like buying deep out-of-the-money puts provide tail hedges.