Practical Criteria for Disruption of the Economic Equilibrium in Contract Adaptation: Iranian Law in Light of International Commercial Instruments

Abstract

In today’s turbulent economic environment, contracts are frequently affected by unforeseeable changes that disrupt their original economic equilibrium and render the performance of contractual obligations difficult. The absence of objective standards for accurately identifying a “fundamental change of circumstances” has resulted in inconsistent judicial decisions and the possibility of abuse. This article aims to develop and present a practical framework for identifying the disruption of economic equilibrium in the process of contract adaptation. Accordingly, the central question is: On the basis of which practical and measurable criteria may adjudicatory authorities establish the occurrence of a fundamental change of circumstances? The research hypothesis is founded on the proposition that exclusive reliance on a single criterion is ineffective and that the accurate determination of such a situation requires the combined application of both modern and traditional criteria. This study adopts a descriptive–analytical approach and draws upon comparative analysis of international instruments. The findings indicate that although customary and quantitative criteria are most frequently applied in judicial practice, the use of structural criteria—including supply-chain collapse and technological obsolescence—is essential in modern contracts. Therefore, the systematic organization of these criteria not only promotes commutative justice but also ensures the stability and continuity of commercial relationships.