Labor Unions, Operating Flexibility, and the Cost of Equity

We study whether the constraints on firms' operations imposed by labor unions affect firms' costs of equity. The cost of equity is significantly higher for firms in more unionized industries. This effect holds after controlling for several industry and firm characteristics, is robust to endogeneity concerns, and is not driven by omitted variables. Moreover, the unionization premium is stronger when unions face a more favorable bargaining environment and is highly countercyclical. Unionization is also positively related to various measures of operating leverage. Our findings suggest that labor unions increase firms' costs of equity by decreasing firms' operating flexibility.