This paper provides an early empirical, ex post assessment of how MNEs have responded to the introduction of the Global Minimum Tax (GMT). The GMT, implemented in 2024, represents a fundamental change in international taxation. The paper analyses the realised responses of MNEs exploiting the EUR 750 million threshold to identify causal effects. Specifically, the paper uses group level financial and ownership data from the Orbis database and implements a difference in differences strategy that compares MNEs just above and below the scope defining revenue threshold. The paper evaluates whether the GMT has affected MNE effective tax rates, investment, and employment, and whether firms adjusted their behaviour in anticipation of the reform. The paper includes heterogeneity analysis to assess which company types and sectors drive the results. Finally, the paper uses the analysis on the impact of ETRs to estimate the potential revenues raised by the GMT in its first year of introduction.
