In this paper we analyse various instances of supervisory centralization either implemented or proposed in Europe in the aftermath of the financial crisis and the sovereign debt crisis. Our central thesis is that supervisory fragmentation is a cause of systemic risk, as cooperation amongst national authorities is bound to fail in crisis situations, while the absence of common resolution mechanisms and common deposit guarantee schemes aggravates the costs of a banking crisis and increases the chances of a bailout. We argue, in particular, that the current European supervisory architecture introduced in 2010 substantially belongs to the model of ‘enhanced’ cooperation, despite including elements of the other two models of supervisory centralization (lead supervisor and single supervisor), and is the outcome of a political compromise. Presently, European supervisory authorities, including EBA, coordinate the national ones, rather than supervising financial firms directly. National authorities cooperate in a network (the ESFS) under local mandates and are therefore prone to domestic biases, particularly in crisis situations. [...]