Implied Volatility
Implied volatility (IV) is the market's forward-looking estimate of the magnitude of price fluctuations in an underlying, derived by back-solving an options pricing model from the observed market premium. Higher IV means the market expects larger price swings and results in higher option premiums on NSE.
Implied volatility is not directly observable; it is extracted from the market price of an option by solving the Black-Scholes equation in reverse. If all other inputs — underlying price, strike, time to expiry, risk-free rate, and dividends — are known, the IV is the volatility figure that makes the model price match the observed market price. This makes IV a consensus measure of the market's uncertainty about future price moves.
India VIX, published by NSE, measured the 30-day implied volatility of Nifty 50 options and served as the Indian equivalent of the CBOE VIX. Historically, India VIX spiked sharply around elections, budget announcements, and global risk events such as the COVID-19 outbreak in March 2020. A rising VIX corresponded to rising option premiums, even when the underlying had not yet moved significantly.
Implied volatility is quoted as an annualised percentage. A Nifty IV of 15% implied that the market expected roughly a 15% annualised standard deviation in Nifty's returns. To convert this to a daily expected move, the formula used was IV divided by the square root of 252 (trading days), yielding approximately 0.94% per day. This daily expected range was used by traders to assess whether option premiums were expensive or cheap relative to actual daily price movement.
A key misconception is that high IV is a straightforward signal for a large directional move. High IV reflects uncertainty, not direction. An underlying with high IV has elevated option premiums on both calls and puts, reflecting the market's expectation of large moves in either direction. Buying options when IV is high means paying elevated premiums, and any subsequent contraction in IV will reduce the option's value even if the directional move occurs.
IV rank and IV percentile are tools used to contextualise the current level of implied volatility relative to its historical range. A Nifty IV rank of 80 would indicate that current IV was higher than 80% of IV observations over the prior year, suggesting premiums were relatively elevated. This contextualisation was widely used by options traders on Indian desks to determine whether strategies should lean toward buying or selling premium.