This study seeks the optimal way to promote compatibility between systems of proprietary security rights in Europe. The focus is on security rights over tangible movables and receivables. Compatibility is understood as the absence of cross-border problems, notably uncertain enforceability and unexpected loss of proprietary security rights, or as the availability of workable solutions to them. Current cross-border problems mainly concern enforceability of proprietary security rights against third parties, including a security-provider debtor s other creditors on insolvency.

The study organises the concrete means through which compatibility can be promoted into four main groups, or approaches . These are a centralised substantive approach and three gentler approaches , namely a centralised conflicts-approach, a local conflicts-approach and a local substantive approach. Means within the centralised approaches can be introduced at European Union level, and means within the local approaches at Member State level. The substantive approaches seek to eliminate diversity by unification or harmonisation of substantive law, whereas the conflicts approaches mainly rely on private international law. The study introduces and defends the view that current circumstances call for an integrated approach, which attempts to combine the advantages and avoid the disadvantages of all four approaches. The feasibility of an integrated approach can be confirmed, and its content determined, only by way of a division of labour between the four approaches. This requires choices between the concrete means within each of the four approaches.

To guide that division of labour, the study proposes a set of objectives with a view to capturing the essence of what can be regarded as desirable development towards greater compatibility. The objectives are: foreseeability, derived from the economic functions of proprietary security rights; responsiveness, derived from certain evolutionary aspects of the law; and division of unforeseeability costs, derived from a transnational conception of justice. Importantly, the tension between foreseeability and responsiveness gives rise to a theory of how to reconcile the need for certainty in credit markets and the more general need for the law to adapt to different and changing economic and social circumstances and value choices.

The set of objectives provides criteria for choices between the concrete means within the four approaches. If the proposed objectives are accepted, the choices guided by them can be taken as the optimal way of promoting compatibility, which completes the research.