GDX offers investors exposure to some of the largest gold mining companies in the world, thereby delivering what can be thought of as “indirect” exposure to gold prices. Because the profitability of gold miners depends on the prevailing market price for the goods that they sell, these stocks will generally exhibit a strong correlations to movements in spot gold prices. When gold prices go up, gold miners make more money (and vice versa). It should be noted, however, that this relationship is not perfect; in certain environments, gold miner stocks and physical gold prices can move in opposite directions, and correlation between the two can be less than perfect.