‘At the expense of’: linking claimant and defendant in the law of unjust enrichment

This paper argues that, accepting the division of unjust enrichment claims into enrichment by rights and by value, attribution mechanisms in proprietary restitutionary (eg rescission) and personal restitutionary claims are based on failure to realise exchange potential either of the value of a thing or rights to the thing. It suggests both can therefore be based on corrective justice, as corrective justice is concerned with intentional transactions in which the defendant receives value or rights the exchange potential of which are not properly realised or realisable for the claimant’s benefit. It further argues that recent case law in the United Kingdom Supreme Court supports this view by requiring intentional transactional links between claimant and defendant and that case law in both proprietary (tracing) and personal cases is coalescing around this understanding. The view that a ‘but-for’ link between claimant and defendant suffices in unjust enrichment claims is therefore wrong.