Big Banks and Macroeconomic Outcomes: Theory and Cross-Country Evidence of Granularity
Franziska Bremus, Claudia M. Buch, K. Russ, Monika Schnitzer
NBER Working Paper No. 19093,
2013
Abstract
Does the mere presence of big banks affect macroeconomic outcomes? In this paper, we develop a theory of granularity (Gabaix, 2011) for the banking sector, introducing Bertrand competition and heterogeneous banks charging variable markups. Using this framework, we show conditions under which idiosyncratic shocks to bank lending can generate aggregate fluctuations in the credit supply when the banking sector is highly concentrated. We empirically assess the relevance of these granular effects in banking using a linked micro-macro dataset of more than 80 countries for the years 1995-2009. The banking sector for many countries is indeed granular, as the right tail of the bank size distribution follows a power law. We then demonstrate granular effects in the banking sector on macroeconomic outcomes. The presence of big banks measured by high market concentration is associated with a positive and significant relationship between bank-level credit growth and aggregate growth of credit or gross domestic product.
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Bank-specific Shocks and the Real Economy
Claudia M. Buch, Katja Neugebauer
Journal of Banking and Finance,
No. 8,
2011
Abstract
Governments often justify interventions into the financial system in the form of bail outs or liquidity assistance with the systemic importance of large banks for the real economy. In this paper, we analyze whether idiosyncratic shocks to loan growth at large banks have effects on real GDP growth. We employ a measure of idiosyncratic shocks which follows Gabaix (forthcoming). He shows that idiosyncratic shocks to large firms have an impact on US GDP growth. In an application to the banking sector, we find evidence that changes in lending by large banks have a significant short-run impact on GDP growth. Episodes of negative loan growth rates and the Eastern European countries in our sample drive these results.
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Shocks at Large Banks and Banking Sector Distress: The Banking Granular Residual
S. Blank, Claudia M. Buch, Katja Neugebauer
Journal of Financial Stability,
No. 4,
2009
Abstract
Size matters in banking. In this paper, we explore whether shocks originating at large banks affect the probability of distress of smaller banks and thus the stability of the banking system. Our analysis proceeds in two steps. In a first step, we follow Gabaix and construct a measure of idiosyncratic shocks at large banks, the so-called Banking Granular Residual. This measure documents the importance of size effects for the German banking system. In a second step, we incorporate this measure of idiosyncratic shocks at large banks into an integrated stress-testing model for the German banking system following De Graeve et al. (2008). We find that positive shocks at large banks reduce the probability of distress of small banks.
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