In a model with a continuum of imperfectly substitutable laborers and endogenous skill premiums, this paper derives optimal tax formulas as functions of social welfare weights and a small set of estimable statistics. It first demonstrates that differential capital tax, based on capital’s effect on skill premiums, is desirable even in the steady state, while nonlinear capital tax is not desirable under an additively separable utility function. It then explores both uniform and sector-specific capital income tax (UCIT and SCIT), with a sector corresponding to a type of laborer. Numerical application to U.S. taxation delivers an inverted U-shaped relationship between the SCIT rate and sectoral wage. The optimal SCIT rate on the top-income sectors increases with the elasticity of substitution between the sectoral products and amounts to a net return tax of $45.9\%$. Reform from UCIT to SCIT compresses wage gaps between the top ten percent and others considerably. It especially favors the median-income individuals whose wages are increased as high as $3.8\%$. Due to production inefficiency, switching from UCIT to SCIT implies small welfare gains ($0.07\%~0.22\%$ in consumption-equivalent terms).

在具有不完全可替代劳动力和内生技能溢价的连续性的模型中，本文推导了作为社会福利权重函数和少量可估计统计量的函数的最优税收公式。它首先证明，即使在稳定状态下，基于资本对技能溢价的影响，差别资本税也是可取的，而在可加性可分离的效用函数下，非线性资本税是不可取的。然后，它探讨了统一的和特定部门的资本所得税（UCIT和SCIT），其中一个部门对应于一种劳动者。在美国税收中的数字应用在SCIT税率和部门工资之间产生了倒U型关系。$45.9％$。从UCIT到SCIT的改革大大缩小了收入最高的百分之十与其他人之间的工资差距。它特别偏爱那些工资涨幅高达10％的中等收入个人。$3.8％$。由于生产效率低下，从UCIT转换为SCIT意味着福利收益较小（$0.07％〜0.22％$ 以等同于消费的术语）。