How does financial development affect the magnitude of the business cycles fluctuations? We examine this question in a general equilibrium model with heterogeneous agents and endogenous credit constraints based on Kiyotaki (1998). We show that there is a hump‐shaped relationship between the degree of financial frictions and the amplification of unexpected productivity shocks. This nonmonotonic relation is due to the fall in financial frictions having two opposite effects on the response of output. One effect is the reallocation of productive inputs between agent types, which, while active, increases with the fall in financial frictions. The other effect is the change in the demand of inputs, which decreases with the fall in financial frictions. At low levels of financial development, the reallocation effect dominates and a fall in financial frictions increases the amplification of productivity shocks. In contrast, at higher levels of financial development, a fall in financial frictions decreases the shock amplification because the reallocation effect disappears while the effect on the demand of inputs is still present.