Identifying the causal mechanisms how financial flows are routed between consumers, firms, and investors, the associated welfare implications, and how governments and regulators can influence these mechanisms is a capstone objective – be it in response to new European regulations such as capital requirements (Gropp et al., 2019) or bank levies (Bremus et al., 2020), the provision of emergency liquidity by central banks abroad (Kick et al., 2020) or macroeconomic shocks (Lambert et al., 2019, Koetter et al., 2020). It is also a matter of highlighting the effects on financial stability (Bosma et al., 2019) and thus welfare (Gropp et al., 2020) and providing governments and regulators with tools to respond to them, for example within the framework of consultation processes by regulatory institutions (Koetter and Tonzer 2018, 2020). Insights generated from independent research enable us to critically assess past policy actions and to develop evidence-based policy advice when tackling economic and ultimately societal challenges.

Are central banks fountains of funds or dikes against toxic floods of risk?

If money is so pivotal to the economic system, where does it come from? The monopoly to generate financial funds rests with central banks. Only they can create – or retire – legal tender and are usually mandated to ensure that the correct quantity of financial funds circulates in the economy to facilitate the exchange of goods and services while maintaining stable prices by conducting monetary policy.

To master this challenging task, scientific methods are needed to isolate cause and effect and separate identifiable mechanisms from spurious correlations. Economic theory guides the articulation of hypotheses that can be tested with econometric techniques. The role of financial economics scholars is to develop scientific tools in the form of theoretical models and empirical analyses and apply them to data to aid policy makers in their decision-making. As such, our task is to generate facts with so-called positive economic analyses. The resulting information can then be the input to normative analyses that evaluate economic policy, i.e. an assessment conditional on value judgements.

Two features of central banks are particularly important to the research at the Financial Markets department in this context. First, despite the obvious direct effect of central bankers’ choices and actions on each of our lives, their executives are not elected, but appointed. Contrary to the legislative and the executive branch of democratically organised societies, central bankers are thus not directly legitimised by voters. This lack of a direct mandate by the sovereign – us voters –creates oftentimes tensions and allegations that “bureaucrats” govern our financial affairs (Eichler et al., 2018; Delis et al., 2020). The second feature is that Germany does not conduct national monetary policy for itself. To foster economic integration in a single market, we introduced the common currency on January 1, 2002. Until today, the euro replaced local currencies in 20 European states that constitute the European Monetary Union (EMU). Around 340 million people therefore no longer face exchange rate risk, enjoy cheaper cross-border payments and other financial transactions, and can therefore trade and travel with fewer economic frictions. The common currency with all its benefits also entails, however, that monetary policy is conducted for the entire EMU by the European System of Central Banks (ESCB) and not for any single nation alone.

Devising monetary policy for a group of countries that often differ quite substantially in terms of economic and financial conditions poses a challenge to the European Central Bank (ECB), which conducts the monetary policy for the EMU. For example, EU law is not always transposed immediately into national law. The delayed completion of the European Banking Union (Koetter et al., 2019; Grothe et al., 2019) is thus leading to different reactions to ECB measures such as the current purchase programmes to mitigate adverse economic shocks. Disagreement on the appropriate policy stance became glaringly obvious in the wake of the sovereign debt crisis that struck Greece, Ireland, Portugal, Italy, and Spain starting in 2010.

A particularly controversial response by the ECB to combat soaring risk premia was to purchase stressed sovereign bonds in secondary markets. One of the first asset purchase programmes (APP) was the Securities Market Programme (SMP), absorbing sovereign bonds from the five stressed EMU members on the order of 218 billion euros between May 10, 2010 and February 29, 2012.

This approach to relief stress from financial markets and institutions represented a paradigm shift in ECB policy making and quickly became subject to vocal criticism, especially by many German commentators. The main concern was that buying sovereign debt would represent a stealth re-financing of governments by the ECB, thereby sowing the seeds of future lack of budgetary discipline in stressed member states. Overly easy re-financing conditions were feared to invite excessive risk-taking and strengthen the undesirable mutual dependence of national governments and “their” banks if the latter hold a lot of sovereign bonds on their balance sheets.

The Financial Markets department conducts a range of research projects that assess APP’s and other policies to strengthen financial system resilience. One specific project activated research collaboration networks with the ECB and Deutsche Bundesbank to investigate if the SMP had indeed detrimental effects. Alternatively, we wanted to learn if this unconventional policy of the ECB had positive effects, such as easing credit conditions and fostering economic activity (Koetter, 2020; Antoni et al., 2019).

Guided by our task as researchers to provide facts, we were the first to connect detailed data on each transaction of each security during the SMP by the ECB with equally detailed security-level data about the holdings of all bonds and stocks by all German banks in the five years before and after the SMP programme.

Figure 1 illustrates that around 1/6 of all regional German banks were exposed to the SMP shock in terms of holding at least one security that was eventually purchased under the SMP. The low shares of SMP-securities’ nominal value relative to banks’ entire security portfolios shown in the bottom panel further suggest that anticipation of the APP was unlikely.

This “big data” exercise allowed us then to test whether the ECB’s APP caused banks with access to the programme to behave differently compared to banks without access to the additional ability to raise refunding from the ECB at favorable terms. Exploiting detailed quarterly bank-level data reported to Deutsche Bundesbank revealed very little support for the various dramatic concerns raised. In fact, the average German bank with SMP access increased lending by 4% during the five post-SMP years relative to banks without access, a much faster-paced growth as illustrated in Figure 2.

This result holds in particular for regional banks, which expanded commercial lending to their mainly small and medium enterprise customers, but contracted mortgage lending. Loan portfolio composition changes mitigate concerns about ultra-loose monetary policy to fuel real estate prices. At the same time, no significantly different risk-taking behaviour could be detected.