The introduction of market mechanisms matters for industrial relations. In the German hospital sector, national liberalization policies have put immense pressure on local management and worker representatives and led to the growth of a low-wage sector. In case studies of eight hospitals, we find some locales where market making has led to union revitalization and mobilization, but this effect varies. Using an eight-way comparison, we infer a configuration of three aspects of the local political economy – labour markets, politics, and codetermination rules – that together provide a well fitting explanation for both variation and change.