The Normative Influence of the UNIDROIT Principles of International Commercial Contracts on Courts

One of the key developments in international commercial law is the elaboration of codified non-state rules by international organisations. This article analyses how codified non-state rules become normative through the example of the UNIDROIT Principles of International Commercial Contracts (UPICC), with a specific focus on their influence on courts. The UPICC were first published 20 years ago and frequency of usage is modest. Despite this they have become accepted general principles of international commercial law. This acceptance has come mainly through the application of the UPICC in state courts and arbitral tribunals to interpret the applicable law as well as through their usage in legislative drafts. As such they have become a standard with a normative value in international commercial law. This demonstrates how international organisations influence the legal principles and international commercial law practice that is applied by the courts.