Assessing Damages in Investment Treaty Arbitration in the Context of Pillar Two: The Interplay Between the Charging Provisions and the Principle of Compensatio Lucri Cum Damno

Assuming that the implementation of Pillar Two Rules into the domestic legislation of several jurisdictions potentially violates international investment agreements (IIAs), the question remains as to how damages should be calculated. While it seems logical to equate them with the tax burden that is imposed, the principle of compensatio lucri cum damno provides that, if the wrongdoer’s actions result in both losses and gains for the victim, these benefits must be offset against his obligation to indemnify. Doing so warrants that reparation will not put the aggrieved party in a more advantageous position because it suffered the damage. This article explores the interplay between the Pillar Two charging provisions and the principle of equalization of benefits, emphasizing the necessity of considering such interactions when assessing damages in investor-state arbitration. It concludes that the OECD guidance on the QDMTT payable generates two possible undesirable outcomes over the quantum of damages. If the guidance is followed, the damages that are awarded may, at a maximum, reimburse the qualified domestic minimum top-up tax (QDMTT) collected whichwould likely not nullify the overall Pillar Two impact on an multinational enterprise (MNE) group; if not followed, benefits arising to the investor would need to be considered in the assessment of damages and reduce the compensation to an insignificant amount.