Aggregate Implications of a Credit Crunch: The Importance of Heterogeneity
利用一个包含金融摩擦和异质性的模型，研究信贷紧缩如何映射为不同的总体楔子，发现三种模型变体中信贷紧缩表现为效率、投资和劳动楔子，且企业所有者总体的欧拉方程无扭曲，揭示了代表性代理人模型识别经济波动来源的局限性。
We take an off-the-shelf model with financial frictions and heterogeneity, and study the mapping from a credit crunch, modeled as a shock to collateral constraints, to simple aggregate wedges. We study three variants of this model that only differ in the form of underlying heterogeneity. We find that in all three model variants a credit crunch shows up as a different wedge: efficiency, investment, and labor wedges. Furthermore, all three model variants have an undistorted Euler equation for the aggregate of firm owners. These results highlight the limitations of using representative agent models to identify sources of business cycle fluctuations.