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The Volatility Smile


Synopsis


Emanuel Derman, Michael B. Miller

Summary

Chapter 1: Introduction to the Volatility Smile

* Explanation: The volatility smile is a phenomenon where implied volatility increases with strike price for out-of-the-money options, and decreases with strike price for at-the-money options.
* Example: For a stock trading at $100, the implied volatility for an option with a strike price of $90 might be 30%, while the implied volatility for an option with a strike price of $110 might be 40%.

Chapter 2: Causes of the Volatility Smile

* Skewness Risk: Investors demand a premium for holding options that are exposed to skewness risk, which is the risk that the underlying asset will have extreme price movements.
* Kurtosis Risk: Investors also demand a premium for holding options that are exposed to kurtosis risk, which is the risk that the underlying asset will have more frequent than normal price spikes.
* Liquidity Risk: Out-of-the-money options are typically less liquid than at-the-money options, which can lead to a higher implied volatility for out-of-the-money options.

Chapter 3: Empirical Evidence for the Volatility Smile

* Historical Data: Empirical studies have shown that the volatility smile is a persistent phenomenon across different markets and time periods.
* Option Pricing Models: Option pricing models, such as the Black-Scholes model, cannot fully explain the volatility smile.
* Market Microstructure: Market microstructure factors, such as order flow and bid-ask spreads, can also contribute to the volatility smile.

Chapter 4: Trading Strategies Involving the Volatility Smile

* Skewness Trading: Investors can profit from the volatility smile by buying options that are exposed to skewness risk.
* Kurtosis Trading: Investors can also profit from the volatility smile by buying options that are exposed to kurtosis risk.
* Volatility Arbitrage: Investors can use the volatility smile to create volatility arbitrage strategies, which involve buying and selling options with different strike prices and expirations.

Chapter 5: The Volatility Smile in Risk Management

* Stress Testing: The volatility smile can be used to assess the risk of extreme market events.
* Portfolio Optimization: The volatility smile can be incorporated into portfolio optimization models to improve risk-adjusted returns.
* Risk Metrics: The volatility smile can be used to develop new risk metrics that capture the complex dynamics of market volatility.

Chapter 6: The Volatility Smile in Practice

* Case Study: A hedge fund manager uses the volatility smile to implement a successful skewness trading strategy.
* Interview with a Market Maker: A market maker explains how they manage the risk associated with the volatility smile.
* Regulatory Implications: The volatility smile has implications for financial regulation, such as the setting of margin requirements and risk capital standards.