Proportionality and Deference in Investor-State Arbitration: Balancing investment protection and regulatory autonomy

By Caroline Henckels, Published by Cambridge University Press, October 2015

The study examines how investment tribunals have balanced the interests of host states and foreign investors in determining state liability in disputes concerning the exercise of public power. It proposes a new methodology, combining the proportionality analysis with an institutionally sensitive approach to the standard of review, in order to lead to more consistent and coherent decisions and greater certainty, and to safeguard states’ regulatory autonomy. Available at