This paper quantifies the aggregate effects of financing constraints. We start from a standard dynamic investment model with collateral constraints. In contrast to the existing quantitative literature, our estimation does not target the mean leverage ratio to identify the scope of financing frictions. Instead, we use a reduced-form coefficient from the recent corporate finance literature that connects exogenous debt capacity shocks to corporate investment. Relative to a frictionless benchmark, collateral constraints induce losses of 7.1% for output and 1.4% for total factor productivity (TFP) (misallocation). We show these estimated losses tend to be more robust to misspecification than estimates obtained by targeting leverage.AN ACCUMULATING BODY OF EVIDENCE shows the causal effect of financing frictions on firm-level outcomes. For instance, Lamont (1997) shows that a reduction in oil prices leads nonoil subsidiaries of oil companies to reduce capital expenditures, Rauh (2006) exploits nonlinear funding rules for defined benefit pension plans to identify the role of internal resources on corporate investment, Gan (2007) and Chaney, Sraer, and Thesmar (2012) use variation in local house prices as shocks to firms' collateral value and show that collateral values affect investment, Chodorow-Reich (2014) combines the default of Lehman