Overlapping area represents the amount of risk that can be diversified away by holding CDK Global Inc and Broadridge Financial Solutions in the same portfolio assuming nothing else is changed. The correlation between historical prices or returns on Broadridge Financial and CDK Global 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 CDK Global are associated (or correlated) with Broadridge Financial. Values of the correlation coefficient range from -1 to +1, where. The correlation of zero (0) is possible when the price movement of Broadridge Financial has no effect on the direction of CDK Global i.e. CDK Global and Broadridge Financial go up and down completely randomly.