what does a volatility smile tell you 
volatility smiles are created by implied volatility changing as the underlying asset moves more itm or otm the more an option is itm or otm the greater its implied volatility becomes implied volatility tends to be lowest with atm options the volatility smile is not predicted by the black scholes model which is one of the main formulas used to price options and other derivatives the black scholes model predicts that the implied volatility curve is flat when plotted against varying strike prices based on the model it would be expected that the implied volatility would be the same for all options expiring on the same date with the same underlying asset regardless of the strike price yet in the real world this is not the case volatility smiles started occurring in options pricing after the 1987 stock market crash they were not present in u s markets beforehand indicating a market structure more in line with what the black scholes model predicts after 1987 traders realized that extreme events could happen and that markets have a significant skew the possibility for extreme events needed to be factored into options pricing therefore in the real world implied volatility increases or decreases as options move more itm or otm 1also the volatility smile s existence shows that itm and otm options tend to be more in demand than atm options demand drives prices which affects implied volatility this could be partially due to the reason mentioned above extreme events can occur causing significant price shifts in options the potential for large shifts is factored into implied volatility example of how to use the volatility smilevolatility smiles can be seen when comparing various options with the same underlying asset and same expiration date but different strike prices if the implied volatility is plotted for each of the different strike prices then there may be a u shape the u shape is not always as perfectly formed as depicted in the graph above for a rough estimate of whether an option has a u shape pull up an options chain that lists the implied volatility of the various strike prices if the option has a u shape then options that are itm and otm by an equal amount should have roughly the same implied volatility the further itm or otm the greater the implied volatility with the lowest implied volatilities near the atm options if this is not the case then the option does not align with a volatility smile the implied volatility of a single option also could be plotted over time relative to the price of the underlying asset as the price moves in or out of the money the implied volatility may take on some form of a u shape this can be useful if seeking an option that has lower implied volatility in this case choose an option near the money if looking for greater implied volatility choose an option that is further itm or otm remember though as the underlying asset moves closer to or farther from the strike price this will affect the implied volatility therefore maintaining a portfolio of options with a specific implied volatility will require continual reshuffling not all options align with the volatility smile before using the volatility smile to aid in making trading decisions check to make sure that the option s implied volatility actually follows the smile model the difference between a volatility smile and a volatility skew smirkwhile near term equity options and forex options lean more toward aligning with a volatility smile index options and long term equity options tend to align more with a volatility skew the skew smirk shows that implied volatility may be higher for itm or otm options limitations of using the volatility smilefirst it is important to determine if the option being traded actually aligns with a volatility smile the volatility smile is one model that an option may align with but implied volatility could align more with a reverse or forward skew smirk also due to other market factors such as supply and demand the volatility smile if applicable may not be a clean u shape or smirk it may have a basic u shape but could be choppy with certain options showing more or less implied volatility than would be expected based on the model the volatility smile highlights where traders should look if they want more or less implied volatility yet there are many other factors to consider when making an options trading decision 