Defending institutional power? Unions’ positions towards the extension of collective agreements in Finland, Germany, and the Netherlands

Abstract Statutory bargaining extensions of collective agreements are an effective instrument to stabilise multi-employer bargaining. For unions, this means tensions between the logic of influence and membership. On the one hand, the extension constitutes a central institutional power resource. On the other hand, it might impede collective action if workers are covered without contributing. This article analyses unions’ preferences for extensions in Germany, the Netherlands and Finland, three countries that differ in union power and the trajectories of their bargaining institutions. The article has two findings. First, unions value extensions as a power resource because they prevent wage dumping. Second, union-supporting institutions counteract free-riding. Given new legislative efforts at the EU level, statutory extensions could become more important in the future.