Monetary Policy Bank Leverage And Financial Stability

This paper develops a model to assess how monetary policy rates affect bank risk-taking. In the model, a reduction in the risk-free rate increases lending profitability by reducing funding costs and increasing the surplus the monopolistic bank extracts from borrowers. Under limited liability, this increased profitability affects only upside returns, inducing the bank to take excessive leverage and hence risk. Excessive risk-taking increases as the interest rate decreases. At a broader level, the model illustrates how a benign macroeconomic environment can lead to excessive risk-taking, and thus it highlights a role for macroprudential regulation.

We present evidence of a risk-taking channel of monetary policy for the U.S. banking system. We use confidential data on the internal ratings of U.S. banks on loans to businesses over the period 1997 to 2011 from the Federal Reserve’s survey of terms of business lending. We find that ex-ante risk taking by banks (as measured by the risk rating of the bank’s loan portfolio) is negatively associated with increases in short-term policy interest rates. This relationship is less pronounced for banks with relatively low capital or during periods when banks’ capital erodes, such as episodes of financial and economic distress. These results contribute to the ongoing debate on the role of monetary policy in financial stability and suggest that monetary policy has a bearing on the riskiness of banks and financial stability more generally.

This paper develops a dynamic bank model to show that expansionary monetary shocks can increase bank risk-taking through higher leverage. Lower monetary policy rates increase lending profitability which can encourage the bank to take more leverage to finance new loans. In the presence of limited liability, the increase in leverage and risk can be excessive. However, the relationship can be non-monotonic. When the bank cannot issue equity, a small reduction in monetary policy rates can reduce excessive risk-taking, whereas a large one can increase it. When the bank can issue equity but adjusting dividends is costly, lower monetary policy rates always induce excessive risk-taking and the effect is quite persistent. In this model, capital requirements work better than loan-to-value caps in reducing excessive risk taking because they are closer to the source of the distortion.

​Due to the lack of political salience that financial stability policy enjoys in tranquil economic times, this policy field lends itself particularly well to capture – the more so the more important the role of banks is in the financial system. Gundbert Scherf’s research focuses on this nexus between integrated banking, supranational monetary policy and national banking regulation. He finds that national level differences in financial systems and related institutions explain and drive variation in regulatory financial stability policy across countries.

Traditional measures of leverage in the financial system tend to reflect bank balance sheet data. The paper argues that these traditional, bank-centric measures should be augmented by considering pledged collateral in the financial system since pledged collateral provides a measure of an important part of nonbank funding to banks. From a policy perspective, the paper suggests that a broader view on leverage will enhance our understanding of global systemic risk, and complement the theoretical work in this field by providing a link from micro-level leverage data to macro aggregates such as credit to the economy.

How does monetary policy impact upon macroprudential regulation? This paper models monetary policy's transmission to bank risk taking, and its interaction with a regulator's optimization problem. The regulator uses its macroprudential tool, a leverage ratio, to maintain financial stability, while taking account of the impact on credit provision. A change in the monetary policy rate tilts the regulator's entire trade-off. We show that the regulator allows interest rate changes to partly "pass through" to bank soundness by not neutralizing the risk-taking channel of monetary policy. Thus, monetary policy affects financial stability, even in the presence of macroprudential regulation.

We present evidence of a risk-taking channel of monetary policy for the U.S. banking system. We use confidential data on banks' internal ratings on loans to businesses over the period 1997 to 2011 from the Federal Reserve's survey of terms of business lending. We find that ex-ante risk taking by banks (measured by the risk rating of new loans) is negatively associated with increases in short-term interest rates. This relationship is more pronounced in regions that are less in sync with the nationwide business cycle, and less pronounced for banks with relatively low capital or during periods of financial distress.

Using firm-level data for approximately 1,000 bank and nonbank financial institutions in 22 countries over the past 15 years we study the impact of prolonged monetary policy easing on risk-taking behavior. We find that the leverage ratio, as well as other measures of firm-level vulnerability, increases for banks and nonbanks as domestic monetary policy easing persists. Cross-border effects are also notable. We find effects of roughly similar magnitude on foreign financial sector firms when the U.S. eases policy. Results appear robust to a variety of specifications, and to be non-linear, with risk-taking behavior rising most quickly at the onset of monetary policy easing.