Competing Forums in Global Tax Governance: OECD , UN and the Prospects of Multilateral Cooperation

Global tax governance appeared to reach a breakthrough in 2021, when the OECD/G20 Inclusive Framework agreed a global minimum tax promising effective coordination against tax avoidance and tax competition. We show how that promise has since come under strain. First, the United States' repeated threats to withdraw and its successful push for exemptions, culminating in the 2025 Side‐by‐Side Package, undermine the reform from above. Second, many jurisdictions are hollowing it out from within: adopting only its domestic revenue floor without its enforcement arms, or redesigning tax incentives so that competitive positions are preserved inside formally qualified rules. Third, the regime's long‐standing participation gap, sharpened by these developments, has driven a forum shift towards the United Nations, where negotiations on a Framework Convention are advancing in a less contentious manner than expected. Drawing on 18 elite interviews and documentary analysis, we argue that global tax governance stands at a crossroads: neither forum yet offers a model that is both effective and broadly acceptable.