Between 2010 and 2015, EU governments negotiated consecutive reforms to the governance of the eurozone which, taken together, represent perhaps the most significant deepening of European integration in modern times. What factors determined the outcome of these negotiations? Did some countries exert greater influence on the agreed reforms than others? We provide the first systematic assessment of the bargaining success of different countries in the reform of the eurozone. We evaluate the explanatory power of three potential sources of bargaining success – power, preferences, and coalitions – based on statistical analysis of new and unique data on the positions of all EU member states on all key reform proposals. Our findings are three-fold. First, contrary to the conventional narrative, the negotiations produced no clear winners and losers. Second, states’ power resources were of limited importance for bargaining success. Third, the negotiations involved a considerable amount of compromise and reciprocity, with member states trading gains and concessions within and across issues. The conclusions carry general importance for our understanding of bargaining power in EU policy-making.