Volatility Cone
A multi-window chart that shows whether implied volatility is genuinely elevated or cheap relative to its own historical distribution.
Definition
A volatility cone is a visual tool that plots the statistical distribution of historical volatility at multiple lookback horizons — typically 10, 20, 30, 60, and 90 calendar days — and superimposes current implied volatility on top. For each horizon, the cone draws the minimum, 25th percentile, median, 75th percentile, and maximum of realised volatility observed over a long sample period, producing a funnel shape that widens toward shorter tenors. The resulting "cone" lets traders instantly see where today's IV sits inside the range of everything the market has experienced before.
Why it matters
In Indian F&O markets, implied volatility can swing dramatically around events — Union Budget announcements, RBI monetary policy meetings, quarterly earnings, or sudden global shocks. A raw IV number like 18% tells you very little on its own; a volatility cone tells you that 18% sits at the 80th historical percentile for a 30-day window, making options meaningfully expensive relative to past realisations. This context is essential for strategy selection: high-percentile IV favours premium-selling approaches like short straddles or strangles, while low-percentile IV favours debit spreads or long options where the edge lies in cheap optionality. On NSE, where Nifty 50 and Bank Nifty weekly expiries create a dense calendar of short-dated contracts, the cone is especially useful for comparing IV across the 7-day versus 30-day tenor before choosing an expiry.
How it works
To build the cone, collect daily closing prices for the underlying over a long history (typically 2–5 years). For each lookback window N, compute the annualised realised volatility as the standard deviation of log returns over the trailing N trading days, scaled by √252. Roll this calculation forward in time to produce a time-series of realised volatilities for each window. Arrange the resulting distributions into percentile bands and plot them against days-to-expiry on the x-axis. Overlay today's term structure of implied volatility — one point per listed expiry — and read off the percentile rank at each tenor. When the IV curve pierces the upper band, the market is pricing in significantly more volatility than history suggests is warranted; when it dips below the median, options are below fair value relative to historical norms.
Example
Suppose it is three weeks before a major RBI rate decision. The 20-day realised volatility for Nifty 50 has been running around 12% annualised. However, the front-month implied volatility is reading 22%. Plotting these on the volatility cone, you notice that 22% sits at the 92nd historical percentile for the 20-day tenor — meaning options have been this expensive or more expensive only 8% of the time over the past four years. A trader observing this might consider a short strangle on Nifty weekly or monthly options, collecting elevated premium while targeting a reversion toward the median. The cone does not predict the future but quantifies the historical precedent for the current pricing.
See live IV across Nifty expiries
Compare implied volatility across weekly and monthly contracts on TradePulse's live option chain.