Trade unions are often argued to cause allocative inefficiencies and to lower welfare. We analyze whether this evaluation is also justified in a Cournot-oligopoly with free but costly entry. If input markets are competitive and output per firm declines with the number of firms (business...

Empirical evidence suggests that the bargaining power of trade unions differs across firms and sectors. Standard models of unionization ignore this pattern by assuming a uniform bargaining strength. In this paper, we incorporate union heterogeneity into a Melitz (2003) type model. Union...