Abstract:
Global tax governance has long struggled with ineffectiveness, as reflected in rising corporate tax avoidance that costs governments hundreds of billions of dollars annually. In response, the Organisation for Economic Cooperation and Development (OECD)/G20 advanced the most ambitious initiative to date - the global minimum tax under its Two-Pillar Solution - which began to take effect in 2024. Yet this reform faces significant challenges: the United States insists on recognition of its unilateral minimum tax, developing countries offer limited support for the initiative, and carve-outs threaten to undermine the reform's effectiveness. In 2024, the United Nations launched negotiations on a parallel Framework Convention on International Tax Cooperation, which was instigated by developing countries. Drawing on 13 semi-structured interviews and analysis of relevant documents, this report finds that while the OECD emphasises effectiveness, the UN prioritises participation. Neither forum currently ensures a reform process that is both effective and participatory, and future progress will depend on addressing this trade-off.