汇率稳定与最优托宾税征收制度——基于NK-DSGE模型的模拟分析与政策评估

Foreign Exchange Rate Stability and Optimal Tobin Tax Rule:Simulation Analysis and Policy Evaluation Based on DSGE Model

通过使用一个包含有托宾税以及外汇储备因素的新凯恩斯DSGE模型,本文设计了3种不同的托宾税规则并分为7种情况进行讨论,从而对托宾税在抑制汇率波动方面的效果进行了系统的考察。研究结果表明,一项恰当的托宾税政策能够增强市场在抗击外部风险冲击方面的能力,但若税制设计得不合理则可能会适得其反。通过对比不同托宾税规则之间的效果,本文认为一项最优的税制应当尽量减少来自政府的干预。此外,模拟结果部分地验证了"三元悖论"中"边界解"要优于"角点解"的观点。从模拟分析的结果来看,无论是资本完全自由流动的情况还是资本管制相对严格的情况,在稳定汇率的效果上都无法达到最优——最优的托宾税政策应当介于两者之间。

This paper researches on Tobin Tax’s effect on decreasing foreign exchange volatility with a NKDSGE model containing the elements of Tobin Tax and foreign exchange by designing three different Tobin Tax rules under seven conditions.The results suggest that a proper Tobin Tax policy can contribute to resisting external risks of foreign exchange rate while an improper one is just the opposite.We find a well-designed rule should try to diminish government intervention through comparing different effects of Tobin Tax rules.Furthermore,our simulation results partly confirm the conclusion of some scholars that in Impossible Trinity theory,an internal or border policy is more likely better than a corner one.Seen from the outcomes of simulation analysis,neither in the condition of completely free capital flows nor in the strict capital controls can the exchange rate stability effect be optimal.An optimal Tobin Tax policy rule should be somewhere between strict capital controls and completely free capital flows policy.