Does the mere presence of big banks affect macroeconomic outcomes? Gabaix (2011) shows that idosyncratic shocks can have aggregate effects if the distribution of firm sizes in manufacturing follows a power law distribution. Our contribution is two-fold. First, we expand the theory of granularity...

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...