Productivity, Prices, and Concentration in Manufacturing: A Demsetzian Perspective
从德姆塞茨视角出发，利用1982-2012年美国制造业数据，发现集中度上升与生产率增长相关，利润率扩大主要由生产率提升而非价格上涨驱动，质疑加强反垄断的必要性。
Concentration and price-cost margins have increased since the 1980s in many industries. These developments have raised concern about weakened competition and resulting harm to consumers and the need for tougher antitrust enforcement. In 1973 Harold Demsetz cautioned against inferring weakened competition from high or rising margins and concentration. He argued that this correlation between margins and concentration could arise from productivity differences across competitive firms. This paper studies the interplay between concentration, prices, and productivity across US manufacturing industries over two 15-year periods from 1982 to 2012. The consistent pattern is that high and rising concentration has been associated with better productivity growth. I show that widening margins, whether related to concentration or not, are mainly driven by productivity gains rather than prices, as in the competitive process outlined by Demsetz. Skepticism about tougher antitrust policy may be warranted: this would risk harm to productivity without benefiting consumers.