How IV Rank and IV Percentile Compare Historical Option Volatility
Summary
The document defines implied volatility rank (IVR) and implied volatility percentile (IVP) as measures of current implied volatility relative to an asset’s history, commonly a one-year window. IVR locates current IV within the historical high-to-low range; IVP measures the share of observations below the current level. Both can help contextualize whether options are relatively expensive or cheap for that underlying. The article gives formulas and a worked example using a short series of volatility readings.
The two measures can diverge because IVR is strongly affected by extreme highs or lows, while IVP can shift sharply when current IV crosses a cluster of past observations. The examples show how a single outlier leaving the lookback window changes IVR, and how small IV moves can change IVP substantially. The author cautions that neither metric predicts a reversal: volatility can cluster, remain at extremes, or set new highs or lows. Readings may inform context, but they do not guarantee mean reversion or establish a trading signal by themselves.
Key ideas
- IVR scales current implied volatility within its historical minimum-to-maximum range.
- IVP measures the percentage of historical observations below current implied volatility.
- Extreme observations can distort IVR until they leave the selected lookback period.
- IVP may move abruptly when current IV crosses a dense cluster of historical readings.
- Low or high IVR and IVP readings do not ensure that volatility will reverse.
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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.