Overlapping area represents the amount of risk that can be diversified away by holding ETFS Commodity Securities Ltd and Atlas Copco AB 0R82 in the same portfolio assuming nothing else is changed. The correlation between historical prices or returns on Atlas Copco AB and ETFS Wheat 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 ETFS Wheat ETC are associated (or correlated) with Atlas Copco. Values of the correlation coefficient range from -1 to +1, where. The correlation of zero (0) is possible when the price movement of Atlas Copco AB has no effect on the direction of ETFS Wheat i.e. ETFS Wheat and Atlas Copco go up and down completely randomly.