日本大阪大學 Yukihiro Nishimura 蒞臨演講
主題：Minimum tax, Tax haven and Activity Shifting

大綱: 
Abstract: Contrary to the claims in previous researches, under a regime of non-linear income tax and linear commodity taxes, a tax reform towards uniform taxes on a subset of commodities may not be welfare-improving. Furthermore, distortions of production that alter relative wages can improve welfare by influencing mimickers’ consumption choices and thus relaxing incentive compatibility constraints. We also identify conditions for optimal uniform taxation within separated consumption groups. Specifically, to neutralize heterogeneous cross-substitution effects across income classes, uniform commodity taxes require parallel income effects, so the restrictions on the Engel curves cannot be dispensed with even under non-linear income taxation. Also, given that the incentive consideration reduces the scope for redistribution, Mirrlees (1976, Optimal tax theory: a synthesis. Journal of Public Economics 6, 327‒358) emphasized the redistributive effects of commodity taxes (which include capital income tax), which reduces the effective tax wedge on labor income. We revert to the unidimensional case to show that the optimal labor wedge can become higher after the introduction of the optimal commodity taxes/subsidies when labor complements are subsidized. Among the classic results of income taxation, decreasing marginal taxes on the middle class, including the mode of the income distribution, remains valid with commodity taxes and without separability in the utility function.

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