Testing for Market Power under the Two-Price System in the U.S. Copper Industry

Before 1978, most of the U.S. domestic copper production and an important fraction of the imports were traded at a price set by the major U.S. producers. Simultaneously, the rest of the world was trading copper at prices determined in auction markets. This two-price system ended in 1978, when the largest U.S. producers began using the Comex price of refined copper as a benchmark for setting their prices. Using this regime shift I test empirically the competitive behavior of the US copper industry before 1978. The results show that copper prices were close to the ones predicted by a competitive model of the industry.