AbstractCrisis-induced refugee migration raises questions of fair responsibility-sharing among political territories. This is relevant for nation states and for subnational territories alike. Theories addressing this problem have mainly been developed with regard to international responsibility-sharing. They assume collective action problems when it comes to organising intergovernmental transfer schemes, something which cannot be easily overcome. It is not well understood how effective transfer schemes can be institutionalised when no hierarchical decision-making is in place. Complementary to that perspective, this paper builds upon constructivist institutional theories that suggest paying more attention to guiding ideas, which can be called upon when intergovernmental transfer schemes are at stake, and to criteria of rationality that can legitimately claim to embody this idea. Legitimate criteria of rationality are typically the result of “investments in form”, i.e. social practices which imbue material objects with certain qualities so that they stand for particular guiding ideas. The article tests this assumption empirically by tracing the institutionalisation process of the Königstein key (Königsteiner Schlüssel) as a dynamic formula for determining state quotas in Germany's refugee federalism. While important precedents of physical intergovernmental responsibility-sharing in refugee matters had already existed in West Germany, their translation to the territorial dispersal of non-German asylum seekers was highly controversial in the 1970s. In this case, resorting to the Königstein key proved to be feasible in part because, by then, the formula had already become a symbol of the idea of federal justice through its use in a variety of different and far less controversial policy fields. However, during the recent wave of refugee immigration it has increasingly become the object of critique.