Tax Sovereignty and Investor Protection: Why the Proposed Global Minimum Tax Is not the Final Frontier for Corporate Tax Arbitrage

Over the past decade, international tax governance has evolved with bewildering speed in response to the challenges of digitalization and widespread corporate tax avoidance. Since the launch of the Group of 20 (G20)-Organisation for Economic Co-operation and Development (OECD) base erosion and profit shifting (BEPS) initiative in 2012, 135 countries and 14 international organizations have joined the BEPS Inclusive Framework, committing to implement new global standards on corporate tax, which has already been lauded as a revolution in the architecture of international tax law and policy. Even further expanding the scope of the OECD’s work on international taxation in a landmark announcement in March 2021, the U.S. administration further proposed imposing a global minimum corporate tax at a rate of 21% to be implemented through an international agreement by mid-2021. If the new OECD initiative is agreed, will the plan to implement a minimum corporate tax be fully implemented by G20 members, and if so, will it do enough to address the tax challenges of digitalization embodied in corporate tax arbitrage? Although the evidence suggests legislative and public policy compliance is likely to be high among G20 members, this article argues the minimum tax initiative is unlikely to go far enough to address deficiencies in global tax dispute resolution, which are extremely germane to the success of the proposed minimum tax. As explained in this article, U.S. leaders and global policymakers must enhance the mutual agreement procedure (MAP), a cornerstone of tax dispute resolution, given a growing body of tax litigation in investment law that threatens the implementation of BEPS 2.0. To do so, global policymakers must also reconcile the conflict of norms between tax sovereignty and investor protection contained in the investor-state dispute settlement (ISDS) regime. Only by addressing the conflict between the principles of tax sovereignty and investor protection can they prevent a tidal wave of investor disputes that will challenge the implementation of the minimum tax through national tax laws.