IV Rank
IV Rank (Implied Volatility Rank) is a metric that expresses the current implied volatility of an underlying as a percentile rank relative to its own historical range over a defined lookback period, commonly 52 weeks.
Implied volatility (IV) levels vary widely across stocks and over time, making it difficult to assess whether a given IV reading is high or low in isolation. A stock trading with 40% IV might be cheap for a biotech company that regularly sees 100% IV, but expensive for a blue-chip utility that rarely exceeds 25%. IV Rank solves this by normalizing the current IV reading against the stock's own historical range.
The calculation is straightforward: IV Rank = (Current IV - 52-week IV Low) / (52-week IV High - 52-week IV Low) x 100. If a stock has traded between 20% and 60% IV over the past year and is currently at 50%, its IV Rank is (50-20)/(60-20) x 100 = 75. This means the current IV is at the 75th percentile of its one-year range — historically elevated. A reading above 50 is generally considered high and may favor premium-selling strategies, while below 50 suggests IV is relatively low and may favor premium-buying strategies.
IV Rank is extensively used on platforms like Tastyworks (now Tastytrade), where the founders of that platform have promoted IV Rank as a cornerstone of systematic options trading. Their research suggests that selling premium when IV Rank is above 50 — particularly in strategies like strangles, iron condors, and credit spreads — has historically produced favorable outcomes over large samples because elevated IV tends to mean-revert toward lower levels.
One limitation of IV Rank is that it is sensitive to the lookback period. A 52-week high or low that was reached during an unusual spike (such as during an earnings announcement or a market crash) can compress or distort subsequent readings. A stock that saw 150% IV during a single earnings event will appear to have low IV Rank even at moderate IV levels for months afterward, potentially leading traders to underestimate how rich premium actually is.
IV Rank is distinct from IV Percentile, though the two are related and often confused. Understanding the precise mechanics of each metric — and when each is most appropriate — is important for traders who use volatility-based entry filters to systematically select options positions.