A Tale of (Almost) 1001 Coefficients: Deep and Heterogeneous Effects of the EU-Turkey Customs Union

In view of the deferred start of negotiations for the modernization of the Customs Union between the EU and Turkey (CU-EUT), we look back and analyse the ex post trade consequences of the CU-EUT. Employing up-to-date econometric best practices for regional integration agreements, we quantify both total and heterogeneous trade effects of the CU-EUT. In contrast to most previous studies, our results indicate a significantly positive, large, and robust impact of the CU-EUT, implying an additional increase in EU-Turkey manufacturing trade by 55-65% compared to the previously active Ankara Agreement. We also provide evidence that the CU-EUT significantly increased Turkey’s trade with third countries. Additionally, a substantial heterogeneity in the CUEUT effect is found across different industries as well as for each of its member countries and the direction of trade. We link the heterogeneity of our up to 911 coefficient estimates to differences in initial trade costs and show that it cannot be ascribed to reductions in bilateral tariff rates.