Externalities And Macroprudential Policy

This note overviews macroprudential policy options that have been proposed to address the systemic risks experienced during the recent financial crisis. It contributes to the policy debate by providing a taxonomy of macroprudential policies in terms of the specific negative externalities in the financial system that these policies are meant to address, and discusses their interrelations and some key implementation issues.

As for any form of government intervention, macroprudential policy should be justified by market failures. This paper discusses three key externalities across financial institutions and from financial institutions to the real economy that rationalize the need for macroprudential policy: externalities related to strategic complementarities, fire sales and interconnectedness. We link each externality to recently proposed macroprudential policy tools, and argue that although various tools can correct the same externality, these tools are best seen as complements rather than substitutes.

Macroprudential policies – caps on loan to value ratios, limits on credit growth and other balance sheets restrictions, (countercyclical) capital and reserve requirements and surcharges, and Pigouvian levies – have become part of the policy paradigm in emerging markets and advanced countries alike. But knowledge is still limited on these tools. Macroprudential policies ought to be motivated by market failures and externalities, but these can be hard to identify. They can also interact with various other policies, such as monetary and microprudential, raising coordination issues. Some countries, especially emerging markets, have used these tools and analyses suggest that some can reduce procyclicality and crisis risks. Yet, much remains to be studied, including tools’ costs ? by adversely affecting resource allocations; how to best adapt tools to country circumstances; and preferred institutional designs, including how to address political economy risks. As such, policy makers should move carefully in adopting tools.

I provide an integrated analysis of monetary and macroprudential policies in a model economy featuring a financial friction and a nominal wage rigidity. In this set-up, the monetary authority faces a trade-off between macroeconomic and financial stability: While expansionary counter-cyclical monetary policy prevents involuntary unemployment, it also amplifies an inefficient reallocation of capital across sectors. The main contribution of the analysis is threefold: First it highlights a novel channel through which monetary policy can impact financial stability. Second, it shows that, by itself, monetary policy can significantly mitigate the wedge between the constrained efficient and the competitive allocation. Third, regardless of the availability of macroprudential tools, stabilizing demand is usually not optimal for monetary policy.

The notion of a tradeoff between output and financial stabilization is based on monetary-macroprudential models with unique equilibria. Using a game theory setup, this paper shows that multiple equilibria lead to qualitatively different results. Monetary and macroprudential authorities have tools that impose externalities on each other's objectives. One of the tools (macroprudential) is coarse, while the other (monetary policy) is unconstrained. We find that this asymmetry always leads to multiple equilibria, and show that under economically relevant conditions the authorities prefer different equilibria. Giving the unconstrained authority a weight on "helping" the constrained authority ("leaning against the wind") now has unexpected effects. The relation between this weight and the difficulty of coordinating is hump-shaped, and therefore a small degree of leaning worsens outcomes on both authorities' objectives.

The countercyclical capital buffer (CCB) was proposed by the Basel committee to increase the resilience of the banking sector to negative shocks. The interactions between banking sector losses and the real economy highlight the importance of building a capital buffer in periods when systemic risks are rising. Basel III introduces a framework for a time-varying capital buffer on top of the minimum capital requirement and another time-invariant buffer (the conservation buffer). The CCB aims to make banks more resilient against imbalances in credit markets and thereby enhance medium-term prospects of the economy—in good times when system-wide risks are growing, the regulators could impose the CCB which would help the banks to withstand losses in bad times.

The paper proposes a simple, new, analytical framework for assessing the cost and benefits of macroprudential policies. It proposes a measure of net benefits in terms of parameters that can be estimated: the probability of crisis, the loss in output given crisis, policy effectiveness in bringing down both the probability and damage during crisis, and the output-cost of a policy decision. It discusses three types of policy leakages and identifies instruments that could best minimize the leakages. Some rules of thumb for policymakers are provided.

This note overviews macroprudential policy options that have been proposed to address the systemic risks experienced during the recent financial crisis. It contributes to the policy debate by providing a taxonomy of macroprudential policies in terms of the specific negative externalities in the financial system that these policies are meant to address, and discusses their interrelations and some key implementation issues.