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Glossary

Volatility Smile

A volatility smile is a U-shaped pattern in which options with the same expiration date have higher implied volatility at strike prices far from the market price than near it.

What Is a Volatility Smile?

A volatility smile is the shape that appears when you plot implied volatility against strike price for options that share the same expiration date. If the options were priced by a simple model with one constant volatility figure, the line would be flat. In real markets, the line usually curves upward at both ends, so options with strike prices far below or far above the current price carry higher implied volatility than options struck near the price. Traders call the shape a smile because the curve resembles one.

Why the Pattern Appears

Implied volatility is the volatility figure that, when placed into an option pricing formula, reproduces the price observed in the market. The most widely taught formula, the Black-Scholes model, assumes that an asset's volatility stays constant and that price changes follow a smooth, bell-shaped distribution. Real prices sometimes move sharply, producing what traders call "fat tails," meaning extreme moves happen more often than that distribution predicts. Investors who want protection against large moves are willing to pay more for options at distant strikes, and that demand lifts their implied volatility.

Smile Versus Skew

In some markets the curve is lopsided rather than symmetrical. In many equity index markets, lower strike prices carry higher implied volatility than higher ones. This tilted form is usually called a volatility skew. Currency options more often show a closer to symmetrical smile. Market participants compare these shapes to see how the market prices risk at different price levels, and to check whether an option model fits observed prices.

Why It Matters to Investors

The smile shows that observed option prices do not fully match the simplest pricing assumptions. For an individual investor, it is a reminder that implied volatility is not one fixed number for an asset. It can differ across strike prices and expiration dates, and it reflects the market's expectations about extreme outcomes as well as typical ones. Understanding the pattern helps explain why options with different strikes can be priced very differently even when they share the same expiration and underlying asset.

Updated October 27, 2026. For general education only; not financial, tax or legal advice.

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Related Terms

Implied Volatility (IV)

Implied volatility is the level of future price movement that the market expects for an asset, inferred backward from the current market price of its options.

Strike Price

The strike price is the fixed price at which the holder of an option can buy or sell the underlying asset, such as a stock, when the option is exercised.

Black-Scholes Model (BSM)

A mathematical model that estimates the theoretical fair price of a European-style option using the underlying stock price, strike price, time to expiration, risk-free interest rate, and volatility.

Volatility Skew

Volatility skew is the pattern in which options with the same expiration date carry different implied volatilities at different strike prices, showing how the market prices risk across outcomes.

Historical Volatility (HV)

Historical volatility is a measure of how much an asset's price has fluctuated over a past period, usually expressed as an annualized standard deviation of its returns.

Put Option

A put option is a contract that gives the buyer the right, but not the obligation, to sell a specified amount of an underlying asset at a set price before or on a set expiration date.