We explore the impact of large banks and of financial openness for aggregate growth. Large banks matter because of granular effects: if markets are very concentrated in terms of the size distribution of banks, idiosyncratic shocks at the bank-level do not cancel out in the aggregate but can affect macroeconomic outcomes. Financial openness may affect GDP growth in and of itself, and it may also influence concentration in banking and thus the impact of bank-specific shocks for the aggregate economy. To test these relationships, we use different measures of de jure and de facto financial openness in a panel dataset for 79 countries and the years 1996–2009. Our research has three main findings: First, bank-level shocks significantly impact upon GDP. Second, financial openness tends to lower GDP growth. Third, granular effects tend to be stronger in financially closed economies.

This paper analyzes the effects of bank capital regulation on the link between bank size and volatility. Using bank-level data for 27 advanced economies over the 2000–2014 period, we estimate a power law that relates the volume of a bank’s loan portfolio to the volatility of loan growth. Our analysis reveals, first, that more stringent capital regulation weakens the size-volatility nexus. Hence, in countries with more stringent capital regulation, large banks show, ceteris paribus, lower loan portfolio volatility. Second, the effect of tighter capital requirements on the size-volatility nexus becomes stronger for the upper tail of the bank size distribution. This is in line with capitalization decreasing with bank size, such that larger banks tend to be more affected by increasing capital requirements. Third, in countries with higher sectoral capital buffers, the size-volatility nexus is weaker.