Standard Deviation Three Year

This is a measure of the range of a stock's monthly return performance. A high standard deviation indicates that a stock's range of performance has been wide--that is, relatively volatile--and a low figure indicates less historical volatility. It is an annualized statistic based on the trailing 36 monthly returns.


When a stock has a high deviation figure, the range of performance is very wide, indicating a greater potential for volatility.


Morningstar calculates this figure in-house using the trailing monthly total returns to derive the monthly standard deviations, which are then annualized.