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