732 The last few years have witnessed a growing sophistication and assertiveness of African states in dealing with foreign investors. One particular manifestation of this can be seen in the growing trend of African states,  particularly those with energy and natural resources, seeking to renegotiate existing investment contracts in order to change the economic balance of those contracts and extract further value from them, write Joseph Otoo (pictured), Senior Associate, and David Elikwu, Trainee Solicitor, Mayer Brown.