Using a novel cross-European dataset on bank internationalization, the paper accounts for organizational and geographic complexity and evaluates its impact on systemic risk and how both the 2008–09 global financial crisis and the 2010–11 European sovereign debt crisis might have modified such an impact. Ahead of the crisis (2005–07), results suggest that bank complexity materially reduces systemic risk and enhances stability, as it encourages banks to take on more diversified risks. While such a relation is inverted during the crisis (2008–11) and after the crisis (2012–13), consistent with the view that, during distress times, international banks have less ability to monitor cross-border risks. Further evidence show that, regardless of the period, the effect of complexity on systemic risk is accentuated for ‘too-big-too-fail’ banks and banks with strong activity diversity. Conversely, complex banks with merger-acquisition history and banks operating networks of foreign branches mitigate systemic risk during the acute crisis and the later stage of the crisis, respectively. The results are robust to the use of alternative measures of systemic risk and complexity, and numerous additional tests. Findings bear critical policy implications for financial regulations.

We empirically investigate how bank internationalization, organizational complexity, and geographical complexity stemming from foreign-affiliate type and geographic dispersion affect parent bank stability and profitability. We base our analysis on unique, hand-collected data for the worldwide locations of subsidiaries and branches of EU banks. Our results show that internationalization benefits bank stability by reducing default risk, and it is significantly associated with lower earnings volatility but poorer profitability. With regard to foreign organizational complexity, banks with both foreign subsidiaries and foreign branches are more stable than banks with foreign branches exclusively, which are more stable than banks with only foreign subsidiaries. Nevertheless, higher geographic complexity is associated with lower default risk, higher volatility in earnings, and higher profitability. Further investigations on the sovereign debt crisis and bank size indicate that the sovereign debt crisis in 2011 amplified the relationship and our findings mainly hold for small banks.