A statistical measure that captures the dispersion of data points in a data series in relation to the mean. In finance, it is used by investors and analysts to determine the total risk per unit of return of an investment. Differently stated, it is a measure of volatility that a firm (or a fund/ portfolio, etc.) takes on in relation to the amount of its expected return.

The coefficient of variation is the ratio of the standard deviation (SD) of a data series to the expected mean.

It is also known as relative standard deviation or for short as CoV or CV.