Property, Subsidiarity, and Unjust Enrichment

Abstract

The relationship between claims in unjust enrichment and other kinds of claims is variable among legal systems. Many civilian systems, but not the common law, recognize a principle of "subsidiarity" for unjust enrichment claims; the meaning of this principle, however, varies widely among systems. The author first unpacks the variety of ways in which unjust enrichment can be and is "subsidiary" to other claims in a number of legal systems (the common law, German law, and Quebec law). He then proposes a model of subsidiarity to answer the question why, and to what extent, unjust enrichment should be subsidiary. His conclusion is that the common law will need to move towards the recognition of such a principle, and that there is much to learn from the German solutions.