Long-run impacts of unions on firms: New evidence from financial markets, 1961-1999

David S. Lee, Alexandre Mas

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88 Scopus citations


We estimate the effect of new private-sector unionization on publicly traded firms' equity value in the United States over the 1961-1999 period using a newly assembled sample of National Labor Relations Board (NLRB) representation elections matched to stock market data. Event-study estimates show an average union effect on the equity value of the firm equivalent to $40,500 per unionized worker, an effect that takes 15 to 18 months after unionization to fully materialize, and one that could not be detected by a short-run event study. At the same time, point estimates from a regression discontinuity design-comparing the stock market impact of close union election wins to close losses-are considerably smaller and close to zero. We find a negative relationship between the cumulative abnormal returns and the vote share in support of the union, allowing us to reconcile these seemingly contradictory findings.

Original languageAmerican English
Pages (from-to)333-378
Number of pages46
JournalQuarterly Journal of Economics
Issue number1
StatePublished - Feb 2012

ASJC Scopus subject areas

  • Economics and Econometrics

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