Understanding downside put skew

Compare lower-strike volatility and premium with the loss exposure that the put creates.

By OptionsKing. Publisher and editorial methods.

Downside put skew describes a pattern in which lower-strike puts have higher implied volatility than comparable options near the stock price. It is a description of option prices expressed through a model. It does not make the lower strike a loss-free source of extra premium.

Describe the same-expiration comparison

Suppose fictional Harbor is $50. Its $50-strike options have IV of 25%, while a lower $40 put has IV of 35%, for the same expiration. The lower strike is priced 10 volatility points higher under the chosen convention.

The $40 put can still have a smaller dollar premium because it is farther out of the money. Comparing IV holds prices in volatility units; comparing cash receipts uses dollars. Both are useful when clearly distinguished.

Work through a put outcome

For a separate payoff illustration, suppose one standard $40 put sells for $0.50 per share, receiving $50. Reserve $4,000 for a possible purchase. Ignore costs, interest, and taxes.

If Harbor later gaps to $25 and the put is assigned, the investor pays $4,000 for shares worth $2,500. Subtract the $50 premium from the $1,500 shortfall: the economic loss is $1,450.

Even if the put had received $1.00 per share instead, the loss at the same share value would be $1,400. Another $50 of credit reduces the loss by $50; it does not change the $4,000 purchase obligation. These payoff quotes are illustrative, not prices derived from the earlier IV readings.

Understand why the shape may arise

Investors may value protection against large declines, and option sellers may require compensation for that exposure. The resulting prices can contain both beliefs about outcomes and compensation for bearing risk.

IV is not a direct event probability. Delta is a local price sensitivity, and using its magnitude as an exact probability also requires assumptions that generally do not hold. A model output cannot establish the real-world frequency or size of losses on its own.

Evaluate the whole position

Compare the potential purchase with current holdings, cash reserves, and a plausible adverse scenario. Check liquidity at the actual strike rather than relying on the appearance of the curve.

Skew can help explain why two contracts carry different model IVs. The decision to sell one still requires a forward-looking view of the exposure and the price actually available.

Sources

• Cboe, The Adventures of Volatility Markets
• OIC, Cash-Secured Put
• OIC, Understanding Options Greeks

Rules and thresholds above were checked against these documents on October 17, 2026. Exchange and broker rules change. Confirm anything you are about to act on with your own broker.

Keep reading

• Volatility smile and skew
• Choosing a put strike
• The wheel strategy explained

Do the math on your own trade

• Position size calculator calculate contract counts under stated account limits.
• Assignment probability calculator explore model estimates and their limits.
• Cash-secured put calculator purchase obligation, break-even, and expiration result.

Every price in this article is an illustrative worked example, not a quote. Read Volatility for the rest of the series, and the disclaimer before you act on any of it. Selling options carries real risk of loss, and the loss can be far larger than the premium you collected.