Macroeconomic Fluctuations with HANK & SAM: an Analytical Approach
构建了一个结合异质性主体和新凯恩斯摩擦的HANK模型，并引入劳动力市场的搜索与匹配摩擦，分析了内生收入风险对经济周期的影响，发现当风险逆周期时，经济可能陷入高失业稳态，泰勒原理不足以消除不确定性，且名义刚性与不完全市场会放大冲击效应。
Abstract Recently developed HANK models, which combine Heterogeneous Agents and New Keynesian frictions, have had a considerable impact on macroeconomics. However, due to the complexity of such models, the literature has focused on numerically solved models and therefore little is known about their general properties. This paper presents a tractable HANK model that integrates Search and Matching (SAM) frictions in the labor market. The model features an endogenous idiosyncratic earnings risk, which may be procyclical or countercyclical. When this risk is countercyclical, which we argue is the empirically plausible case, there is a downward pressure on real interest rates in recessions due to a precautionary savings motive. We show that in this setting (a) the economy may get stuck in a high-unemployment steady state, (b) the Taylor principle is insufficient to eliminate the local indeterminacy of the intended steady state, and (c) nominal rigidities and inincomplete markets are complementary in terms of amplifying the impact of shocks on the macroeconomy.