Small change, big impact? Organisational membership rules and the exit of employers' associations from multiemployer bargaining in Germany

German employers' associations first introduced a so‐called “bargaining‐free” membership (BFM) category in 1990, giving companies the option to join and access services while avoiding the obligations arising to regular members from industry‐level collective agreements with unions. To explain how this phenomenon contributes to change in the German political economy, we investigate why some associations offer their members BFM status whereas others have refused to introduce this option. Controlling for influences such as size and industry, our multivariate analysis of survey data shows that four sets of influences are positively associated with BFM: the role of courts' judicial decisions as “door openers,” structural characteristics of diverging business environments, the evaluation of multiemployer bargaining by the leadership of the association, and the strategic choices of associations.