In this publication, Section I defines the concepts of direct and indirect expropriation and reviews the variety of measures that can constitute an expropriation. Section II focuses on the core issue of establishing an indirect expropriation: the recent treaty practice on defining indirect expropriation as well as arbitral practice. Section III discusses the differences between compensation for a lawful expropriation and reparation for unlawful expropriations, as well as the question of valuation of investments. Section IV offers options which policy makers and negotiators may wish to consider.