We document the evolution of market power based on firm-level data for the U.S. economy since 1955. We measure both markups and profitability. In 1980, aggregate markups start to rise from 21% above marginal cost to 61% now. The increase is driven mainly by the upper tail of the markup distribution: the upper percentiles have increased sharply. Quite strikingly, the median is unchanged. In addition to the fattening upper tail of the markup distribution, there is reallocation of market share from low- to high-markup firms. This rise occurs mostly within industry. We also find an increase in the average profit rate from 1% to 8%. Although there is also an increase in overhead costs, the markup increase is in excess of overhead. We discuss the macroeconomic implications of an increase in average market power, which can account for a number of secular trends in the past four decades, most notably the declining labor and capital shares as well as the decrease in labor market dynamism.

I use matched sampling techniques to analyze whether firms that start exporting become more productive, controlling for the self selection into export markets. To this end, I use micro data of Slovenian manufacturing firms operating in the period 1994-2000. Overall I find that export entrants become more productive once they start exporting. The productivity gap between exporters and their domestic counterparts increases further over time. These results also hold at the industry level and are robust to other controls that may be associated with increased productivity, such as private ownership. Using information on the (firm-level) destination of exports, I find that the productivity gains are higher for firms exporting towards high income regions.JEL Code: L1, D24

for useful discussions at early stages of this project and seminar participants at several institutions and conferences. We also thank the Editor, Jean-Marc Robin, and three anonymous referees for insightful comments and suggestions. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peerreviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.