SecurityRatty: An Option with a Negative Implied Volatility?

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An Option with a Negative Implied Volatility?

2006-08-14 06:27:00 by Jomni in Risk Management Quant

Previously, we talked about cases when an option will have a negative value. This time, it was asked in Wilmott if there are real-life cases where options have negative implied vols.

Here's my take on the subject matter:

Since implied volatilities are derived values, based on observed market parameters and a model or formula, it is indeed possible to have negative results. But does it make sense? Intuitively, we would think that the volatility measure should only be positive and it does not make sense if negative. I think negative implied vols are a result of either a misspecification in the model, or mispricing by the market (an arbitrage opportunity, as mutley pointed out).