Introduction

The renegotiation and adaptation of contractual obligations is a common occurrence in all types of long-term agreements and in particular of investment contracts. There are probably very few investment contracts which during their existence have not been renegotiated and adapted by the parties to take account of changing circumstances or prerogatives.[1] These changes are driven by the common desire of the parties to make their relationship work. They are sometimes formalised in new contractual documents but are also often only reflected by the parties' conduct in the fulfilment ...