Volatility is the measure of the state of instability.
Volatility (finance) frequently refers to the Standard Deviation of the change in value of a Financial Instrument with a specific time horizon. It is often used to quantify the Risk of the instrument over that time period. Volatility is typically expressed in annualized terms, and it may either be an absolute number (''$5'') or a fraction of the initial value (''5%'').
