Optimal Fiscal Policy in a Model with Uninsurable Idiosyncratic Income Risk
研究了在标准不完全市场模型中，面对不可保险的异质性收入风险时，最优财政政策如何设计资本税、劳动税、转移支付和债务，发现短期资本税有效促进再分配，最优政策使转移支付增加约50%，福利收益三分之二来自再分配。
Abstract We study optimal fiscal policy in a standard incomplete-markets model with uninsurable idiosyncratic income risk, where a Ramsey planner chooses time-varying paths of proportional capital and labour income taxes, lump-sum transfers (or taxes), and government debt. We find that (1) short-run capital income taxes are effective in providing redistribution since the tax base is relatively unequal and inelastic; (2) an increasing pattern of labour income taxes over time mitigates intertemporal distortions from capital income taxes; (3) the optimal policy increases overall transfers, calibrated initially to the US welfare system, by roughly $50\%$; (4) two-thirds of the welfare gains come from redistribution and the remaining third come mostly from insurance; and (5) redistribution also leads to a more efficient allocation of labour via wealth effects on labour supply—lower productivity households can afford to work relatively less.