Bank Capitalization Heterogeneity and Monetary Policy

This paper shows that heterogeneity in bank capitalization ratios plays a crucial role in the transmission of monetary policy to bank lending. First, I offer new empirical evidence on how banks’ lending responses to monetary policy shocks depend on their capitalization ratios. Highly capitalized banks reduce their lending more after a monetary tightening, even after controlling for bank liquidity, size and market power in the deposit market. I also document how highly capitalized banks have a riskier portfolio, as measured by loan charge-off rates, and default rates on their loans increase relatively more after a tightening in monetary policy. I then construct a dynamic macroeconomic model that rationalizes the empirical evidence through the interaction of the heterogeneous recovery technologies of banks facing a risk-weighted capital constraint. In particular, after an increase in the policy rate, the model predicts that loan rates and default probabilities increase in both sectors. Highly capitalized banks with a riskier portfolio are more sensitive because the risk-weighted capital constraint affects them more, so they contract lending more. In a counterfactual analysis, I find higher capital requirements amplify the effects of monetary policy