The Existence of International Unchangeable and Changeable Trade Usage

The lessons of article 20 UCP 500 are not restricted to the technical issues of the practice of documentary credits, they illuminate important issues of the valid sources of law in both a National (English and welsh common law) and transnational (UCP) law. The status of the UCP as a codification of trade usage and the importance of this role, even in a commercially sophisticated jurisdiction like England and Wales is well illustrated by the tale of the de minimis rule. The power of privatised, or self-regulatory transnational law, is intimately linked to the dynamic relationship, and on occasion tension between promulgation and acclamation. An awareness of the distinction between trade usage de facto and de juris is necessary if we are to advance our understanding of the functioning of international markets and legal structures. This paper is an attempt to advance this developing area of legal discourse and to reflect upon the potential value of empirical study in the field.