I study the aggregate implications of micro-level lumpy investment in a model consistent with the empirical dynamics of the real interest rate. The elasticity of aggregate investment with respect to shocks is procyclical because more firms are likely to make an extensive margin investment in expansions than in recessions. Matching the dynamics of the real interest rate is key to generating this result because it disciplines the interest-elasticity of investment and avoids counterfactual behavior of the model that would otherwise eliminate most of the procyclical responsiveness. Therefore, data on interest rates place important discipline in aggregating micro-level investment behavior. (JEL D25, E13, E22, E23, E43, G31, H25)

We study the role of financial frictions and firm heterogeneity in determining the investment channel of monetary policy. Empirically, we find that firms with low default risk—those with low debt burdens and high “distance to default”— are the most responsive to monetary shocks. We interpret these findings using a heterogeneous firm New Keynesian model with default risk. In our model, low‐risk firms are more responsive to monetary shocks because they face a flatter marginal cost curve for financing investment. The aggregate effect of monetary policy may therefore depend on the distribution of default risk, which varies over time.

Abstract We argue that the network of investment production and purchases across sectors is an important propagation mechanism for understanding business cycles. Empirically, we show that the majority of investment goods are produced by a few “investment hubs,” which are more cyclical than other sectors. We embed this investment network into a multisector business cycle model and show that sector-specific shocks to the investment hubs and their key suppliers have large effects on aggregate employment and drive down labor productivity. Quantitatively, we find that sector-specific shocks to hubs and their suppliers account for an increasing share of aggregate fluctuations over time, generating the declining cyclicality of labor productivity and other changes in business cycle patterns since the 1980s.