Using U.S. administrative data, this paper shows that the employment-weighted average labor market concentration has been declining since 1980-the opposite of the change needed to explain the falling labor share. The relationship between wages and labor market concentration has also weakened (become less negative) over that time. Together, these results make labor market concentration an implausible driver of the falling labor share despite a strong, negative relationship between labor market concentration and wages.

are the authors and do not necessarily represent the views of the U.S. Census Bureau. All results have been reviewed to ensure that no confidential information is disclosed (DRB-B0109-CDAR-2018718, DRB-B0110-CDAR-2018-0718, DRB-B0020-CED-20181128, DRB-B0018-CED-20181126, CBDRB-FY19-CMS-8034, and CBDRB-FY21-CED006-0017). Lerner has advised institutional investors in private equity funds, private equity groups, and governments designing policies relevant to private equity. Davis has served as an expert witness in a legal dispute between private equity firms. All errors and omissions are our own. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.At least one co-author has disclosed additional relationships of potential relevance for this research. Further information is available online at http://www.nber.org/papers/w26371.ack NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

are the authors and do not necessarily represent the views of the U.S. Census Bureau. All results have been reviewed to ensure that no confidential information is disclosed (DRB-B0109-CDAR-2018718, DRB-B0110-CDAR-2018-0718, DRB-B0020-CED-20181128, DRB-B0018-CED-20181126, CBDRB-FY19-CMS-8034, and CBDRB-FY21-CED006-0017). Lerner has advised institutional investors in private equity funds, private equity groups, and governments designing policies relevant to private equity. Davis has served as an expert witness in a legal dispute between private equity firms. All errors and omissions are our own. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.At least one co-author has disclosed additional relationships of potential relevance for this research. Further information is available online at http://www.nber.org/papers/w26371.ack NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

are the authors and do not necessarily represent the views of the U.S. Census Bureau. All results have been reviewed to ensure that no confidential information is disclosed (DRB-B0109-CDAR-2018718, DRB-B0110-CDAR-2018-0718, DRB-B0020-CED-20181128, DRB-B0018-CED-20181126, CBDRB-FY19-CMS-8034, and CBDRB-FY21-CED006-0017). Lerner has advised institutional investors in private equity funds, private equity groups, and governments designing policies relevant to private equity. Davis has served as an expert witness in a legal dispute between private equity firms. All errors and omissions are our own. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.At least one co-author has disclosed additional relationships of potential relevance for this research. Further information is available online at http://www.nber.org/papers/w26371.ack NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

are the authors and do not necessarily represent the views of the U.S. Census Bureau. All results have been reviewed to ensure that no confidential information is disclosed (DRB-B0109-CDAR-2018718, DRB-B0110-CDAR-2018-0718, DRB-B0020-CED-20181128, DRB-B0018-CED-20181126, CBDRB-FY19-CMS-8034, and CBDRB-FY21-CED006-0017). Lerner has advised institutional investors in private equity funds, private equity groups, and governments designing policies relevant to private equity. Davis has served as an expert witness in a legal dispute between private equity firms. All errors and omissions are our own. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.At least one co-author has disclosed additional relationships of potential relevance for this research. Further information is available online at http://www.nber.org/papers/w26371.ack NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.