Liquidity when it matters: QE and Tobin's q
利用Kiyotaki-Moore模型分析美英非常规货币政策，展示流动性危机如何导致深度衰退，并说明央行增加流动性的政策如何缓解衰退。
The model of credit-constrained investors developed by Kiyotaki and Moore is used to analyse ‘unconventional monetary policy’ actions taken in the US and UK. We make two contributions. The first is expositional—to show that their model of a liquidity crisis can be represented as a two-equation dynamic system in K (the aggregate capital stock) and q (Tobin's q, the price of capital goods) with saddle-point dynamics. This allows for an intuitive, graphical exposition of the issues and results. The second is to show how a liquidity crisis leads to a deep recession when the assumption of perfect wage and price flexibility is replaced by downwardly rigid wages and prices. As in Del Negro et al., we show how central bank policies to increase liquidity can ameliorate the recession: but we use our simplified model for the purpose. Further, we analyse how fiscal intervention can help combat recession.