The implied volatility smile describes the empirical observation that implied volatility for options with the same expiration date varies across different strike prices. This phenomenon deviates from the constant volatility assumption of the Black-Scholes model. The smile typically shows higher implied volatility for out-of-the-money options compared to at-the-money options.
Pricing
The smile indicates that market participants assign a higher probability to extreme price movements than a standard normal distribution would suggest. This results in out-of-the-money options being priced higher than theoretical models predict. The smile reflects market expectations of tail risk and potential large price swings in the underlying asset.
Risk
For quantitative analysts, the implied volatility smile is a critical input for accurate options pricing and risk management. It highlights the non-flat nature of the volatility surface, requiring adjustments to standard models to accurately calculate option Greeks. Ignoring the smile can lead to significant mispricing and ineffective hedging strategies.
