How Do Banks Respond to Regulatory Capital Requirements?
Abstract
Banks allocate their portfolios across several types of loans and securities. Although a large empirical banking literature finds that stronger capital requirements reduce bank lending, these bank-level studies generally estimate an aggregate elasticity that combines individual asset-level supply elasticities with portfolio substitution. Analyzing counterfactual policies that change individual assets’ regulatory penalties, rather than rescaling bank-level requirements, requires separating these quantities. I develop a new method to separate asset supply elasticities from portfolio substitution by using changes in bank-level requirements that shift each asset’s regulatory penalty according to its risk weight. My method recovers a positive supply elasticity for every asset category and finds that banks’ securities holdings respond more to regulatory costs than loans do. Its predictions match out-of-sample bank portfolio responses to changes in capital regulation. Applying these elasticities to post-crisis capital requirements, I ask whether stronger capital regulation explains banks’ portfolio shift away from lending since the financial crisis. I show that capital requirements account for a relatively small share of large banks’ shift from lending to securities since 2012.
