Covariance is a statistical measure of the extent that 2 variables move in tandem relative to their respective mean (or average) values. In the investment world, it is important to be able to measure how different financial variables interact together.

The use of correlation analysis extends to numerous important fields. For example, in finance, correlation analysis can be used to measure the degree of linear relationships between interest rates and stock returns, money supply and inflation, stock and bond returns, and exchange rates.