What are the effects of taxation on individual/entrepreneurs’ risk-taking behavior? This paper re-examines this old question in a continuous time life-cycle model. We demonstrate that the stream of uncertain income from human capital has systematic effects on demand for the risky physical capital asset. If labor supply is inelastic and real wages are known with certainty, then a labor income tax will reduce holdings of the risky physical asset. However, if there are random fluctuations in labor income, then the effect depends on the nature of interaction between wage risk and investment income risk. A labor income tax may actually raise demand for the risky capital asset if human capital risk and physical capital risk are positively correlated. The idiosyncratic risk and nontradability of human capital also have implications for optimal taxation. When the insurance and disincentive effects are jointly taken into account, a Pareto efficient tax structure implies a strictly positive tax rate.

Wage inequality has been significantly higher in the U.S. than in continental European countries since the 1970s. This report studies the role of labor income tax policies (LITP) for understanding these facts. Countries with more progressive LITP have significantly lower before-tax wage inequality at different points in time. Progressivity is also negatively correlated with the rise in wage inequality during this period. Wage inequality arises from differences across individuals in their ability to learn new skills as well as from idiosyncratic shocks. Progressive taxation compresses the (after-tax) wage structure, thereby distorting the incentives to accumulate human capital, in turn reducing the cross-sectional dispersion of (before-tax) wages. Illustrations. This is a print-on-demand publication; it is not an original.

This article examines how to treat human capital -- perhaps the vast majority of the capital stock -- under an ideal, Haig-Simons income tax. Innate ability, investments in human capital, and uncertainty in future earnings are considered. It is demonstrated that conventional income tax treatment and proposed modifications are closer to implementing a consumption tax than an income tax. Approximating ideal income tax treatment may be feasible, but assessing its desirability would require further inquiry.

A substantial majority of all capital is human capital, and most revenue from the income tax is from returns on human capital, wage income. Nevertheless, work analyzing the comprehensive, accrual ("ideal") income taxation of capital has focused on physical and financial capital. Applying the learning from this work to human capital suggests that human capital is significantly undertaxed under a conventional income tax, the actual result being close to what would be appropriate under a wage or consumption tax. This undertaxation does not, however, directly alter the marginal return to investments in human capital, although it does affect intertemporal behavior and bear on the interpretation of arguments about whether income is a distributively appealing base for taxation.

This paper examines the effects of taxation of human capital, physical capital and foreign assets in a multi-sector model of endogenous growth. It is shown that in general the growth rate is reduced by taxes on capital and labor (human capital) income. When the government faces no borrowing constraints and is able to commit to a given set of present and future taxes, it is shown that the optimal tax plan involves high taxation of both capital and labor in the short run. This allows the government to accumulate sufficient assets to finance spending without any recourse to distortionary taxation in the long run. When restrictions to government borrowing and lending are imposed, the model implies that human and physical capital should be taxed similarly.

One of the best known results in modern public finance is the Chamley-Judd result showing that the optimal tax rate on capital income is zero in the long-run. In this paper, we reexamine this result by analyzing a series of generalizations of the Chamley-Judd formulation. We show that in a model with human capital, if the tax code is sufficiently rich and there are no pure profits from accumulating human capital, then all distorting taxes are zero in the long-run under the optimal plan. In this sense, income from physical capital is not special. To gain a better understanding of these two conditions, we study examples in which they are not satisfied and show that the optimal tax rate on income from physical capital does not go to zero. In those cases where the limiting tax rate is non-zero, we calculate its value for alternative specifications of the marginal welfare cost of taxation. Our results indicate that even for conservative specifications, tax rates of 10% and higher are possible under the optimal code.