Overlapping area represents the amount of risk that can be diversified away by holding All Ords and SPTSX Comp in the same portfolio assuming nothing else is changed. The correlation between historical prices or returns on SPTSX Comp and All Ords is a relative statistical measure of the degree to which these equity instruments tend to move together. The correlation coefficient measures the extent to which returns on All Ords are associated (or correlated) with SPTSX Comp. Values of the correlation coefficient range from -1 to +1, where. The correlation of zero (0) is possible when the price movement of SPTSX Comp has no effect on the direction of All Ords i.e. All Ords and SPTSX Comp go up and down completely randomly.