Volatility is troublesome for many investors. Value changes in your stocks, your portfolio, or an index can keep you up at night -- or worse, push you to make emotional decisions you later regret.

Although there are several ways to measure the volatility of a given security, analysts typically look at historical volatility. Historical volatility is a measure of past performance; it is a ...

Annualized volatility is calculated as standard deviation times square root of periods. High annualized volatility indicates greater price variability and potential risk. Investors use annualized ...