New Trends in U.S. Industrial Concentration

Using weighted concentration ratios for the entire economy, I argue that industrial concentration decreased in the U.S. from 1960 to the early1980s and then began to increase. This rise in the last two decades of the 20th century offsets any counteracting affectsstemming from the growth of use of information technology in production or from imports and appears due primarily to the impact of the merger wave starting in the mid 1980s. I also considerbriefly the relationship between increasing market concentrationand a change in market competition,taking into account the expansion of e-commerce.