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.

In a dynamic setting, housing is both an asset and a consumption good. But should it be taxed like other forms of consumption or like other forms of saving? We consider the optimal taxation of the imputed rent from owner housing within a version of the neoclassical growth model. We find that the optimal tax rate on the imputed rent is quite sensitive to the constraints imposed on the other available tax rates. In general, it is not optimal to tax the imputed rent at the same rate as the business capital income.

The recent literature on endogenous economic growth allows for effects of fiscal policy on long-term growth. If the social rate of return on investment exceeds the private return, then tax policies that encourage investment can raise the growth rate and levels of utility. An excess of the social return over the private return can reflect learning-by-doing with spillover effects, the financing of government consumption purchases with an income tax, and monopoly pricing of new types of capital goods. Tax incentives for investment are not called for if the private rate of return on investment equals the social return. This situation applies in growth models if the accumulation of a broad concept of capital does not entail diminishing returns, or if technological progress appears as an expanding variety of consumer products. In growth models that incorporate public services, the optimal tax policy hinges on the characteristics of the services. If the public services are publicly-provided private goods, which are rival and excludable, or publiclyprovided public goods, which are non-rival and non-excludable, then lump-sum taxation is superior to income taxation. Many types of public goods are subject to congestion, and are therefore rival but to some extent nonexcludable. In these cases, income taxation works approximately as a user fee and can therefore be superior to lump-sum taxation. In particular, the incentives for investment and growth are too high if taxes are lump sum. We argue that the congestion model applies to a wide array of public expenditures, including transportation facilities, public utilities, courts, and possibly national defense and police.

Optimal tax design attempts to resolve a well-known trade-off: namely, that high taxes are bad insofar as they discourage people from working, but good to the degree that, by redistributing wealth, they help insure people against productivity shocks. Until recently, however, economic research on this question either ignored people's uncertainty about their future productivities or imposed strong and unrealistic functional form restrictions on taxes. In response to these problems, the new dynamic public finance was developed to study the design of optimal taxes given only minimal restrictions on the set of possible tax instruments, and on the nature of shocks affecting people in the economy. In this book, Narayana Kocherlakota surveys and discusses this exciting new approach to public finance. An important book for advanced PhD courses in public finance and macroeconomics, The New Dynamic Public Finance provides a formal connection between the problem of dynamic optimal taxation and dynamic principal-agent contracting theory. This connection means that the properties of solutions to principal-agent problems can be used to determine the properties of optimal tax systems. The book shows that such optimal tax systems necessarily involve asset income taxes, which may depend in sophisticated ways on current and past labor incomes. It also addresses the implications of this new approach for qualitative properties of optimal monetary policy, optimal government debt policy, and optimal bequest taxes. In addition, the book describes computational methods for approximate calculation of optimal taxes, and discusses possible paths for future research.

Many studies predict massive job losses and real wage decline as a result of the ongoing widespread automation of production, a trend that may be further aggravated by the COVID-19 crisis. Yet automation is also expected to raise productivity and output. How can we share the gains from automation more widely, for the benefit of all? And what are the attendant equity-efficiency trade-offs? We analyze this issue by considering the effects of fiscal policies that seek to redistribute the gains from automation and address income inequality. We use a dynamic general equilibrium model with monopolistic competition, including a novel specification linking corporate power to automation. While fiscal policy cannot eliminate the classic equity-efficiency trade-offs, it can help improve them, reducing inequality at small or no loss of output. This is particularly so when policy takes advantage of novel, less distortive transmission channels of fiscal policy created by the empirically observed link between corporate market power and automation.

Written by experts in the field, this book uses the modern theory of public finance to analyze tax and pricing policy in developing countries.