This paper develops an account of how economic and political institutions can limit the applicability of principles of justice even in non-relational cosmopolitan conceptions. It shows that fundamental principles of justice underdetermine fair distributive shares as well as justice -based requirements. It argues that institutions partially constitute the content of justice by determining distributive shares and by resolving indeterminacies about justice -based requirements resulting from strategic interaction and disagreement. In the absence of existing institutions principles of justice might not be applicable for assessing distributions or guiding individual action and institutional design. Hence, accepting a specific cosmopolitan conception of justice is insufficient to settle global distributive questions.