. 11. see buch, c., evidenzbasierte wirtschaftspolitik [ https : / / www. bundesbank. de / de / presse / reden / evidenzbasierte - wirtschaftspolitik - 827310 ], keynote speech delivered at the 8th conference for social and economic data, berlin, 2 march 2020. 12. wuermeling, j. and r. roseler ( 2020 ), ein update fur die bankenaufsicht : die digitale agenda von bafin und bundesbank [ https : / / www. handelsblatt. com / meinung / gastbeitraege / gastkommentar - ein - update - fuer - diebankenaufsicht - die - digitale - agenda - von - bafin - und - bundesbank / 26734100. html ], in : handelsblatt, 26 december 2020. 13. see auswirkungen virtueller wahrungen auf die finanzmarkte [ https : / / www. bundesbank. de / de / presse / reden / auswirkungen - virtueller - waehrungen - auf - diefinanzmaerkte - 711074 ], speech delivered in frankfurt am main on 15 january 2018 ; digitalisierung : fur eine balance von innovation und soliditat [ https : / / www. bundesbank. de / de / presse / reden / digitalisierung - fuer - eine - balance - von - innovationund - soliditaet - 762104 ], speech delivered in mainz on 24 september 2018.

was erected. on that date, the ecb assumed responsibility for supervising the 120 largest banks in the euro area – with the accession of lithuania, the number of supervised banks has risen to 123. these 123 banks account for more than 85 % of the aggregate balance sheet of the euro area ’ s banking sector, making the ecb one of the biggest banking supervisors in the world. the idea of european banking supervision was undoubtedly born out of the crisis. the crisis lent new urgency to something that had already been obvious before : in banking and finance, national borders are far less relevant than in other areas of life. such an integrated financial system is certainly desirable for all the well - known reasons, including efficiency gains and risk - sharing. however, that which distributes gains among all of us in good times, forces us all to share the pain in bad times. in an integrated financial system, problems in one country can quickly spread to others. bis central bankers ’ speeches this is what happened during the recent crisis and it made us realise that banking supervision had to adapt – with international banks that operate across borders, isolated supervision was not so “ splendid ” after all. to quote the imf, the european banking union is the “ logical conclusion of the idea that integrated banking systems require integrated prudential oversight ”. to be sure, there was a certain amount of cooperation in supervisory matters before the crisis. there was an exchange between home and host supervisors of internationally active banks. and there were supervisory colleges in which supervisors of global banks convened and shared their insights. however, this was not enough. an integrated financial system cannot be supervised through cooperation, it requires an integrated approach. taking banking supervision from the national level to the european level has three specific benefits. first, european banking supervision makes it possible for banks in the entire euro area to be supervised to the same, high standards. these standards will emerge from sharing insights and empirical findings internationally and taking the best from each national approach to banking supervision. germany, for instance, could benefit from a more quantitative - oriented approach, which has already been adopted by other countries. second, european banking supervision makes it possible to effectively identify and manage cross - border problems. this is essential, because, as i have mentioned, large banks are usually active in more than one country. the failure of the franco - belgian bank dexia in 2011 is a classic example of a case where banking supervision with a cross - border focus could have improved crisis management. another example is german