This paper provides evidence on the impact of European Banking Union (BU) and the associated Single Supervisory Mechanism (SSM) on the risk disclosure practices of European banks. The onset of BU and the associated rules are considered as an exogenous shock that provides the setting for a natural experiment to analyze the effects of the new supervisory arrangements on bank risk disclosure practices. A Difference-in-Differences approach is adopted, building evidence from the disclosure practices of systemically important banks supervised by the European Central Bank (ECB) and other banks supervised by national regulators over the period 2012–2017. The main findings are that bank risk disclosure increased overall following BU but there was a weakening of disclosure by SSM-supervised banks relative to banks supervised by national authorities. We also find that the overall positive effect of the BU on bank disclosure is stronger for less profitable banks and in the most troubled economies of the Eurozone (GIPSI countries), while the negative effect on centrally supervised banks is stronger if bank CEOs act also as chairmen (CEO duality). We interpret these findings in light of the fact that the new institutional arrangements for bank supervision under which the ECB relies on local supervisors to collect the information necessary to act gives rise to inefficiencies with respect to the speed and completeness of the information flow between SSM supervised banks and the ECB, which are reflected in bank disclosure practices.

本文提供了关于欧洲银行业联盟 (BU) 和相关单一监管机制 (SSM) 对欧洲银行风险披露实践影响的证据。BU 的出现和相关规则被视为外生冲击，为分析新监管安排对银行风险披露实践的影响提供了自然实验的环境。采用差异中的差异方法，从 2012 年至 2017 年期间受欧洲中央银行 (ECB) 监管的系统重要性银行和其他受国家监管机构监管的银行的披露实践中建立证据。主要发现是银行风险披露在 BU 之后总体上有所增加，但与受国家当局监管的银行相比，受 SSM 监管的银行的披露力度有所减弱。我们还发现，对于利润较低的银行和欧元区问题最严重的经济体（GIPSI 国家），BU 对银行披露的总体积极影响更强，而如果银行 CEO 也充当以下角色，则对中央监管银行的负面影响更大。董事长（CEO双重身份）。我们根据以下事实来解释这些发现：欧洲央行依赖当地监管者收集采取行动所需的信息的银行监管新制度安排导致 SSM 之间信息流动的速度和完整性方面的低效率银行和欧洲央行，这反映在银行披露实践中。