The proliferation of international institutions means that states can be subject to multiple, overlapping and potentially incoherent international obligations. The regime complexity literature draws attention to this problem but says little about its character and causes. This article investigates whether and why two key components of the international economic surveillance regime – the International Monetary Fund (IMF) and the European Union (EU) – impose conflicting obligations on the same states. Based on a comparative sentiment analysis of more than 400 surveillance documents and using differences in tone as a proxy for incoherence, our results show that the IMF was more pessimistic about member states’ economic policies before the global financial crisis but less so thereafter. Our results suggest that differences in discretionary authority rather than the distribution of power drove such incoherence, with the EU’s fiscal rules encouraging less pessimism before the global financial crisis and more pessimism thereafter.