국제투자분쟁에서의 손해배상액 산정기준에 관한 고찰 －투자자의 위법-부당행위를 중심으로－

In recent investment disputes, it is important to consider investor misconduct in damages determination when the host state’s measure is taken in response to the misconduct. Investor misconduct includes an investor’s activities which violate domestic laws and regulations of the host state as well as activities that are inappropriate in light of the public order and morals of the host state. In case of investor misconduct, arbitral tribunals have evaluated and apportioned responsibilities between the investor and the host state. Arbitral tribunals have applied Article 39 of the Draft Articles on Responsibility of States for Internationally Wrongful Act (ARSIWA) and apportioned the responsibility by taking account of the contribution to the injury by wilful or negligent action or omission of the investor. However, since there is no concrete standard to apply Article 39 in apportioning damages between the parties, arbitral tribunals are allowed to exercise a wide margin of discretion. As a result, some tribunals have apportioned the responsibilities of two disputing parties without considering such factors as types of investor misconduct and its societal impact. The damages determination is the last and critical stage in the investor-state dispute settlement mechanism. The lack of explanation on apportioning damages between parties can raise another problem. Against this backdrop, this paper examines several investment dispute cases and then suggests ways to consider investor misconduct in damages determination. Firstly, the investor misconduct in question shall be appraised under the basic principle of reparation of public international law, the full reparation principle. This means that damages determination shall be made by calculating the actual contribution of the host state to damage incurred by the investor. Secondly, types of investor misconduct shall be duly considered. When an investor contributed to the injury, there are two options in damages determination. One is to mitigate damages accrued to the host state considering the contribution to the injury by the investor, and the other is to exonerate the host state from its responsibility. If the host state has taken wrongful measures in response to such previous investor misconduct causing serious environmental threats or human rights violations, it is necessary to determine whether there is proximate causation between the host state’s measure and the injury.