U.S. Market Concentration and Import Competition
利用美国制造业企业层面的机密普查数据，研究发现进口竞争通过将销售从较小企业重新分配给较大企业并导致企业退出，提高了美国企业的集中度，但外国企业的扩张抵消了这一效应，使得1992至2012年间包含外国销售在内的美国市场集中度保持稳定。
Abstract Many studies have documented that the sales concentration of U.S. producers has risen in recent decades. In this article, we show that this increase was accompanied by more entry and growth of foreign competitors. Using confidential census data covering the universe of all firm sales in the U.S. manufacturing sector, we find that rising import competition increased concentration among U.S. firms by reallocating sales from smaller to larger U.S. firms and by causing firm exit. However, this increase in production concentration was counteracted by the expansion of foreign firms, which reduced domestic firms’ share of the U.S. market inclusive of foreign firms’ sales. We find that once the sales of foreign exporters are taken into account, U.S. market concentration in manufacturing was stable between 1992 and 2012.