We show that weather-related natural disasters in the United States significantly weaken the financial stability of banks with business activities in affected regions. This is reflected in higher probabilities of default, lower z-scores, higher non-performing assets ratios, higher foreclosure ratios, lower returns on assets and lower equity ratios of affected banks in the years following a natural disaster. The effects are economically relevant and highlight the financial vulnerability of banks and their borrowers despite insurances and public aid programs.

The economy is a complex system because market participants do not act independently but adjust their behavior to other agents and to the outcome which emerges from their joint actions (Arthur, 2014). Dependencies among participants can impede policy makers capabilities to influence or steer the course of the economy. Kambhu et al. (2007) argue that to influence developments in financial markets, for instance to prevent crises from spreading, there are only “coarse or indirect options” available for policy makers. Similar to crises which propagate through a complex system, interventions might result in unintended side effects which can also disseminate through the system. Thus, in a complex system, unintended consequences of policy efforts may well be the rule. Policy makers try to ward off or mitigate negative consequences for the economy and society during periods of crisis. For instance, during the Covid crisis large scale support programs for firms in Western economies were set up to avoid bankruptcies. Similarly, during the sovereign debt crisis in the Eurozone, the European Central Bank (ECB) set up large scale asset purchase programs as well as additionally longer-term refinancing operations (LTRO) which provided immediate support to financial market participants’ liquidity positions and thereby prevented a melt-down of the financial system. During these periods, immediate and abundant liquidity supply is of utmost importance. Meanwhile, crisis measures, due to their massive scale and non-specific target group, may entail unknown or unintended side effects for instance on competition among market participants, firms’ investment behavior, or changes in lending strategies and risk taking behavior of banks. Likewise, new regulatory frameworks such as the introduction of new markets can have consequences previously not thought of. For policy makers it is important to know direct effects of policy interventions but also to be aware of the possibility and impact of indirect or unexpected side effects in order to evaluate measures taken and to learn for future design of regulation or intervention.

In der Finanzkrise sind Boni für Bankmanager in die Kritik geraten. Bonussysteme stehen im Verdacht, Anreize für eine zu riskante Kreditvergabe zu setzen. Der vorliegende Beitrag untersucht am Beispiel einer großen internationalen Geschäftsbank, wie sich ein Bonussystem, das ein hohes Volumen neu vergebener Kredite belohnt und den Ausfall von Krediten bestraft, auf das Verhalten von Kreditsachbearbeitern auswirkt. Die Ergebnisse zeigen, dass Kreditsachbearbeiter die Anbahnung neuer und die Überwachung bestehender Kredite verstärken, wenn sie ihren monatlichen Bonus zu verlieren drohen. Eine genauere Prüfung von Kreditanträgen findet dagegen nicht statt. Kreditsachbearbeiter passen ihr Verhalten besonders gegen Monatsende an, wenn die Bonuszahlung herannaht. Langjährige Mitarbeiter reagieren stärker auf das System als jüngere Kollegen. Komplexe Produktivitätsaspekte wie die Teamfähigkeit können mit Bonussystemen nicht erfasst werden.