We study the link between tax progressivity and top income shares. Using variation from Western tax reforms in the 1980s and 1990s and synthetic control method estimation, we find that reductions in tax progressivity had large and lasting positive impacts on top income shares. The effects are largest within the top percentile and almost zero in the lower half of the top decile, and all results are robust to different model specifications, placebo tests in time and space, and controlling for other contemporaneous reforms. Searching for mechanisms, we find that the effects seem to operate mainly through reductions in top marginal tax rates and that the share of capital income in top incomes increased after the reforms, indicating that tax avoidance behavior could explain some of the observed effects.

中文翻译：

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税收改革带来的税收累进性和最高收入证明

我们研究了税收累进性与最高收入份额之间的联系。利用1980年代和1990年代西方税收改革的变化以及综合控制方法的估计，我们发现税收累进性的降低对最高收入份额产生了巨大而持久的积极影响。在最高百分位数中，影响最大，在最高十分位数的下半部，影响几乎为零，并且所有结果对于不同的模型规格，时空安慰剂测试以及控制其他同期改革均具有鲁棒性。在寻找机制时，我们发现这种影响似乎主要是通过降低最高边际税率起作用的，而改革后资本收益在最高收入中所占的份额有所增加，这表明避税行为可以解释一些观察到的影响。