The global minimum tax reform—agreed by more than 130 countries in 2021 and in effect in the European Union and other countries since January 2024—is the biggest change in taxing multinationals in decades if not a century. The reform comes in the wake of sizeable and increasing tax avoidance and a decade of not-so-successful attempts by governments to reduce it. Is the reform an imperfect success story and how will it end? The effects of the global minimum tax on firms and governments are far from clear due to the reform’s complexity, uncertainty about how they will respond to it, and unavailability of suitable timely data. Therefore, to explore the likely impact of the global minimum tax, this special session brings together experts with backgrounds in policy, theory, and empirics. What are the likely short-term impacts on revenue and beyond? What are the likely long-term impacts on behaviour of governments and companies? What does the reform imply for inequalities and how heterogenous are likely to be the impacts across developing and developed countries, and tax havens?