A measure of the fluctuation in the market price of the underlying security. Mathematically, volatility is the annualized standard deviation of returns (annualized standard deviation of a stock's daily price changes). Volatility is a primary determinant in the valuation of options premiums and time value. There are two basic kinds of volatility, implied and historical (statistical). Implied volatility is calculated by using an option pricing model (Black-Scholes for stocks and indices and Black for futures). Historical volatility is calculated by using the standard deviation of underlying asset price changes from clos e to close trading going back 21 to 23 days.
See Also:
Historic Volatility: A measure of actual stock price changes over a specific period of time; usually calculated by taking a stand`ard deviation of price changes over a time period.
Implied Volatility: A measure of the volatility of the underlying stock, it is determined by using option prices currently existing in the market at the time rather than using historical data on the price changes of the underlying stock.
Individual Volatility: The volatility percentage that justifies an option's price, as opposed to historic or implied volatility. A theoretical option pricing model can be used to generate an option's individual volatility when the five remaining quantifiable factors (stock price, time until expiration, strike price, interest rates, and cash dividends) are entered along with the price of the option itself.
Volatility Skew: The theory that options that are deeply out-of-the-money tend to have higher implied volatility levels that at-the-money options. Volatility skew measures and accounts for the limitation found in most options pricing models and uses it to give the tra der an edge in estimating an option's worth.
