With publication of the results of its Comprehensive Assessment at the end of October 2014, the European Central Bank has set the standard for its new mandate as supervisor. But this was only the beginning. The heavy work started in early November, with the day-to-day supervision of the 120 most significant banks in the eurozone under the Single Supervisory Mechanism. The centralization of the supervision in the eurozone will pose a number of challenges for the ECB in the coming months and years ahead. This report analyzes these challenges in detail, drawing on the discussions and presentations in the CEPS Task Force on ECB Banking Supervision. This report was written for and with the help of a cross-sectoral group of experts from banks, supervisory authorities, and academia to stimulate debate and thinking on these matters.