We investigate the relationship between bank complexity and bank risk-taking using German banking data over the period 2005-2017. We find that more complex banking organizations tend to take on more risk, but that this complexity-risk nexus decreases over time. We study how regulatory tightenings inherent in this period, and addressing systemically important banks (SIBs) in general and complexity more specifically, alter banks’ choices of complexity and risk. Banks reduce their complexity in response to regulatory tightenings, as these increase the related regulatory costs. Surprisingly, for SIBs in particular, the reduction of regulatory costs is associated with an increase in diversification benefits. As a result, they are able to lower their idiosyncratic risk more than other banks. The overall complexity-risk nexus is lower after regulatory tightenings. Thus, our results indicate that post-crisis regulation is effective in reducing banks’ complexity-risk nexus.

我们使用2005-2017年期间的德国银行业数据调查银行复杂性与银行冒险行为之间的关系。我们发现，更复杂的银行组织倾向于承担更大的风险，但是这种复杂性风险联系会随着时间的推移而减少。我们研究了在此期间内在固有的监管收紧措施，以及在总体上和更具体地解决系统重要性银行（SIB）时，如何改变银行对复杂性和风险的选择。银行为应对监管紧缩而降低了复杂性，因为这增加了相关的监管成本。出乎意料的是，特别是对于SIB，监管成本的降低与多元化收益的增加相关。结果，与其他银行相比，它们能够降低其特有的风险。监管收紧后，总体复杂性风险联系较低。因此，我们的结果表明，危机后的监管有效地减少了银行的复杂性-风险联系。