Bank Size, Leverage, and Financial Downturns

I construct a macroeconomic model with a heterogeneous banking sector and an interbank lending market. Banks differ in their ability to transform deposits from households into loans to firms. Bank size differences emerge endogenously in the model, and in steady state, the induced bank size distribution matches two stylized facts in the data: bigger banks borrow more on the interbank lending market than smaller banks, and bigger banks are more leveraged than smaller banks.I use the model to evaluate the impact of increasing concentration in US banking on the severity of potential downturns. I find that if the banking sector in 2007 was only as concentrated as it was in 1992, GDP during the Great Recession would have declined by much less than it did, and would have recovered faster