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.

Unconventional monetary policy measures like asset purchase programs aim to reduce certain securities' yield and alter financial institutions' investment behavior. These measures increase the institutions' market value of securities and add to their equity positions. We show that the extent of this recapitalization effect crucially depends on the securities' accounting and valuation methods, country-level regulation, and maturity structure. We argue that future research needs to consider these factors when quantifying banks' recapitalization effects and consequent changes in banks' lending decisions to the real sector.

Bank regulators interfere with the efficient allocation of resources for the sake of financial stability. Based on this trade-off, I compare how different capital requirements affect default probabilities and the allocation of market shares across heterogeneous banks. In the model, banks‘ productivity determines their optimal strategy in oligopolistic markets. Higher productivity gives banks higher profit margins that lower their default risk. Hence, capital requirements indirectly aiming at high-productivity banks are less effective. They also bear a distortionary cost: Because incumbents increase interest rates, new entrants with low productivity are attracted and thus average productivity in the banking market decreases.

We study the impact of sovereign solvency on the private-public savings offset. Using data on 80 economies for 1989–2018, we find robust evidence for a U-shaped pattern in the private-public savings offset in sovereign credit ratings. While the 1:1 savings offset is observed at intermediate levels of sovereign solvency, fiscal deficits are not offset by private savings at extremely low and high levels of sovereign solvency. Particularly, the U-shaped pattern is more pronounced for countries with high levels of foreign ownership of government debt. The U-shaped pattern is an emerging market phenomenon; additionally, it is confirmed when considering foreign currency rating and external public debt, but not for domestic currency rating and domestic public debt. For considerable foreign ownership of sovereign bonds, sovereign default constitutes a net wealth gain for domestic consumers.

Housing is an essential durable consumption good and oftentimes the largest and most important investment a household makes. The way households finance their housing is important not only for expenditure patterns but also for asset accumulation. As Chambers et al. (2009) explain, housing investment, for both residential and nonresidential structures comprises about half of all private investments and the liabilities from home mortgages are approximately equal to two-thirds of gross domestic product. It is very closely linked with the financial market via the housing backed mortgages taken by the majority of home-owners and it is intrinsic to real economic activity.

I propose a financial channel of wage rigidity. In recessions, rigid average wages squeeze cash flows, forcing firms to cut hiring due to financial constraints. Indeed, empirical cash flows and profits would turn acyclical if wages were only moderately more procyclical. I study this channel in a search and matching model with financial constraints and wage rigidity among incumbent workers (but flexible new hires’ wages). While neither feature generates amplification individually, their interaction can account for much of the empirical labor market fluctuations—breaking the neutrality of incumbents’ wages for hiring, and showing that financial amplification of business cycles requires wage rigidity.

We investigate the impact of the French 2012 financial transaction tax on trading activity, volatility, and price efficiency measured by first-order autocorrelation. We extend empirical research by analysing anticipation and reallocation effects. In addition, we consider measures for long-run volatility and first-order autocorrelation that have not been explored yet. We find robust evidence for anticipation effects before the effective date of the French FTT. Controlling for short-run effects, we only find weak evidence for a long-run reduction of trading activity due to the French FTT. Thus, the main impact of the French FTT on trading activity is short-run. We find stronger reactions of low-liquidity treated stocks and a reallocation of trading activity to high-liquidity stocks participating in the Supplemental Liquidity Provider Programme, which is both in line with liquidity clientele effects. Finally, we find weak evidence for a persistent volatility reduction but no indication for a significant FTT impact on price efficiency measured by first-order autocorrelation.

This paper uses novel news ticker data to evaluate the effect of sovereign risk on economic and financial outcomes. The use of intraday news enables me to derive policy events and respective timestamps that potentially alter investors’ beliefs about a sovereign’s willingness to service its debt and thereby sovereign risk. Following the high frequency identification literature, in the tradition of Kuttner (2001) and Guerkaynak et al. (2005), associated variation in sovereign risk is then obtained by capturing bond price movements within narrowly defined time windows around the event time. I conduct the outlined identification for Italy since its large bond market and its frequent coverage in the news render it a suitable candidate country. Using the identified shocks in an instrumental variable local projection setting yields a strong instrument and robust results in line with theoretical predictions. I document a dampening effect of sovereign risk on output. Also, borrowing costs for the private sector increase and inflation rises in response to higher sovereign risk.

I analyze the impact of the formation of universal banks on corporate investment by looking at the gradual dismantling of the Glass-Steagall Act’s separation between commercial and investment banking. Using a sample of US firms and their relationship banks, I show that firms curtail debt issuance and investment after positive shocks to the underwriting capacity of their main bank. This result is driven by unrated firms and is strongest immediately after a shock. These findings suggest that universal banks may pay more attention to large firms providing more underwriting opportunities while exacerbating financial constraints of opaque firms, in line with a shift to a banking model based on transactional lending.