Optimal income taxation with tax avoidance

We determine the optimal income tax schedule when individuals have the possibility of avoiding paying taxes. Considering a convex concealment cost function, we find that a subset of individuals, located in the interior of the income distribution, should be allowed to avoid taxes, provided that the marginal cost of avoiding the first euro is sufficiently small. This contrasts with the results of Grochulski who shows that, using a subadditive cost function, all individuals should report their true income. We also provide a characterization of the optimal income tax curve.     

Optimal tax theory: A synthesis

Necessary conditions for optimal taxation are derived (i) when taxes are constrained to be linear, (ii) when the form of taxation is unconstrained, (iii) when some commodities are subject to nonlinear taxation, the remainder to proportional taxation. Among the results obtained are several that help to determine upon which commodities the tax system ought to bear most heavily. In particular, a criterion for the effect of commodity taxes in the presence of an optimal income tax is found. The paper concludes with a general principle of simple form for optimal economic policies of all kinds.     

Optimal social security tax with myopic agents

Myopic agents lack the foresight to save for their own old age. It is generally believed that correcting myopia is a rationale for a pay-as-you-go (PAYG) pension system. This view has been supported by existing literature showing that the optimal PAYG social security tax should increase when people are more myopic. In this paper we obtain new results opposed to the traditional view. By establishing a very standard general equilibrium OLG model with myopic agents and endogenized marginal product of capital, we show that the optimal social security tax should be lower when people are more myopic. Our numerical analysis also shows that the welfare cost of the social security tax increases with people's degree of myopia. These results suggest that correcting myopia is not a clear rationale for the PAYG social security.     

Optimal tax treatment of the family: Married couples

This paper examines the appropriate tax treatment of the family in a series of analytical models and numerical examples. For a population of taxpaying couples which differ in earning capacity, we drive the optimal tax rates for each potential earner. These rates depend crucially upon own and cross labor supply elasticities and the joint distribution of wage rates. Our results suggest that the current system of income splitting in the United States, under which husbands and wives face equal marginal tax rates, is nonoptimal. Using results from recent econometric studies, and allowing for a sensitivity analysis, the optimal tax rates on secondary workers in the family are much lower than those on primary earners. Indeed, our best estimate is that the secondary earner would face tax rates only one-half as high as primary earners.     

Optimal tax reform in the presence of adjustment costs

The optimal implementation of an efficiency-enhancing capital taxation reform is examined when the government is concerned about arbitrary reform-induced redistributions and investment causes firms to incur adjustment costs. Theoretical results indicate that immediate partial enactment of reform is optimal with concave adjustment costs, while with convex adjustment costs, the optimal reform implementation policy is either (i) immediate partial enactment with sufficiently low adjustment costs, (ii) phased-in partial enactment with intermediate adjustment costs, or (iii) postponed partial enactment with sufficiently high adjustment costs. Numerical results suggest that, relative to the optimal one-step implementation policy, little is gained by phasing-in reform.     

Optimal tax policy and foreign direct investment under ambiguity

We analyze the optimal timing of an irreversible foreign direct investment by a foreign firm and the optimal tax policy by a host country under ambiguity. We derive the optimal GDP level at which the foreign firm switches from exporting to a foreign direct investment. Furthermore, we derive the optimal tax policy by the host country, and analyze the effect of an increase in ambiguity on the optimal tax policy. We show that the host country should reduce the optimal corporate tax rate from the host government’s perspective in response to an increase in ambiguity. Our result is different from the one obtained by Pennings (2005) that shows that an increase in risk induces an increase in the optimal corporate tax rate.     

Optimal indirect taxation with a restricted number of tax rates

This paper analyzes the optimal structure of indirect taxation when the number of available tax rates is smaller than the number of taxable commodities. Such a constraint requires to choose the levels of tax rates and the groups of commodities that will be taxed at equal rates (or exempted). In a partial equilibrium framework, with a single agent and a low amount of tax collection, it is shown that the process of allocation of commodities to groups depends on both price elasticities and consumption spendings. Still, the optimal tax structure displays a weak form of the inverse elasticity rule; consumption spendings influence the size of the fiscal base, and may lead to many tax exemptions.     

Optimal income taxation with tax avoidance and endogenous labour supply

I determine the optimal income tax schedule when individuals both choose endogenously their labour supply and have the possibility of avoiding paying taxes. Considering a convex concealment cost function, I propose a formula for the optimal marginal tax rate, that generalizes the formula of the standard Mirrlees model to the case of tax avoidance. I also show that the results obtained by Casamatta (2021) in the fixed income case hold true when labour supply is endogenous: with a low enough marginal cost of avoidance, it is optimal to let some taxpayers, located in the interior of the skill distribution, avoid taxes.     

Optimal top marginal tax rates under income splitting for couples

This paper provides formulas for optimal top marginal tax rates when couples are taxed according to income splitting between spouses, consumption is taxed, and the skill distribution is unbounded. Optimal top marginal income tax rates are computed for Germany using a dataset that includes the tax returns of all German top taxpayers. We find that the optimal top marginal tax rate converges to about 2/3 and convergence obtains at income levels that are substantially higher than those currently subject to the actual top tax rate.     

Striking a balance: Optimal tax policy with labor market duality

We develop a dynamic general equilibrium model where employers may avoid making social security contributions by offering some workers “secondary contracts.” When calibrated using aggregate tax revenue data, the model delivers estimates of secondary “off the books” employment that are consistent with survey evidence for the EU14 and United States. We investigate the fiscal and welfare effects of varying the avoidable and unavoidable shares of labor income tax while keeping the total wedge constant, and find that increasing the employer component raises hours worked, output, and welfare. Partial labor tax evasion makes tax revenues more elastic, but full tax compliance need not be a welfare enhancing policy mix.     

Optimal income tax under the threat of migration by top-income earners

We examine how allowing individuals to emigrate to pay lower taxes changes the optimal nonlinear income tax scheme in a Mirrleesian economy. An individual emigrates if his domestic utility is less than his utility abroad, net of migration costs — utilities and costs both depending on productivity. A simple formula, that complements Saez's formula obtained in closed economy, is derived for the marginal tax rates faced by top-income earners. It depends on the labour elasticity, the tax rate abroad and the migration costs expressed as a fraction of the utility obtained abroad. The Rawlsian marginal tax rates, obtained for the whole population, illustrate a curse of the middle-skilled. Simulations are provided for the French economy.     

Optimal taxes on wealth and consumption in the presence of tax evasion

This article incorporates tax evasion into an optimum taxation framework with individuals differing in earning abilities and initial wealth. We find that despite the possibility of its evasion a tax on initial wealth should supplement the optimal nonlinear income tax, given a positive correlation between initial wealth and earning abilities. Further, even if income and initial wealth are taxed optimally, it is still desirable to levy a tax on commodities, though it can be evaded as well. Thus, our result provides a rationale for a comprehensive tax system. Optimal tax rates on commodities differ in general, however for the special case of a uniform evasion technology equal rates are optimal if preferences are homothetic and weakly separable.     

Optimal mixed taxation,credit constraints,and the timing of income tax reporting

We study optimal income and commodity tax policy with credit‐constrained low‐income households. Workers receive an even flow of income during the tax year, but report their incomes and make tax payments (receive transfers) at the end of the year. They spend their disposable income on multiple commodities over the year. We show that differentiated subsidies on commodities can be optimal even if the Atkinson–Stiglitz Theorem conditions apply. When the optimal policy leaves low‐income households with binding credit constraints, it may be optimal to subsidize differentially the good that they consume in higher proportion. Uniform subsidies would also relax the credit constraint, but would be more costly to the government since they would equally benefit unconstrained households. Numerical examples suggest that commodity tax differentiation increases with basic needs and with the interest rate at which government borrows.     

A tax discrepancy coefficient resulting from tax evasion or tax expenditures

Tax evasion and tax expenditures introduce discrepancies between taxpayers. In this paper, a tax discrepancy coefficient has been worked out in order to establish, given a constant tax yield, what bigger or smaller amounts taxpayers would have to pay if tax evasion or tax expenditures were completely eliminated. After the definition of the coefficients these are calculated for individual income tax returns in Belgium. Similar coefficients can be established for other types of taxation, such as inheritance tax, corporate income tax or even sales tax (e.g. V.A.T.).     

Optimal taxation and cross-price effects on labor supply: Estimates of the optimal gas tax

This study estimates parameters necessary to calculate the optimal second-best gasoline tax, most notably the cross-price elasticity between gasoline and leisure. Prior theoretical work indicates the importance of this elasticity, but despite this, almost none of the prior studies of commodity taxation (and none of the studies on second-best environmental regulation) actually estimate it. Using household data, we find that gasoline is a relative complement to leisure, and thus that the optimal gasoline tax is significantly higher than marginal damages-the opposite of the result suggested by the bulk of the prior literature. Indeed, even if there were no externalities at all associated with gasoline, the optimal tax rate would still be almost equal to the average gas tax rate in the U.S. Following this approach to estimate cross-price elasticities with leisure could strongly influence estimates of optimal rates for other important commodity or pollution taxes.     

Optimal tax rules and public sector efficiency with an externality in an overlapping generations model

This paper examines optimal tax rules and public sector efficiency, integrating them in a second-best world with pollution by using an overlapping generations model. The second-best world is characterized by the comparative statics of green preferences. The main results obtained are as follows. First, the marginal cost of public funds may be reduced by the externalities, regardless of the choice of taxes. Second, optimal environmental and non-environmental tax rules are additively and directly affected by the dynamic efficiency of capital accumulation per unit labour (DECAL), and indirectly by it, through the efficiency of the public sector. Environmental taxes going beyond Pigovian ones may be welfare-improving if the DECAL is improved by the environmental tax. Even optimal non-environmental tax rules should additively and directly counter the dynamics of pollution to consider the income effects of the optimal tax system for the future. Third, the “additivity property,” or the “principle of targeting,” does not hold even in the absence of incentive compatibility constraints. The essential reasons for this are clarified as follows: distortions that should be countered by taxes; that is, the income effects of the optimal tax system and the DECAL in this model, break the equality between optimal environmental taxes and the externalities measured by governments. Finally, growing environmental concerns may, in fact, increase pollution. The inverse relationship between environmental and labour income taxes may not hold.     

Optimal tax treatment of private contributions for public goods with and without warm glow preferences

Tax-favored contributions for financing some public goods may be a useful part of optimal nonlinear income tax and expenditure policy. There are two sides to the potential gain from subsidized donations. First, for a given level of public good provision, higher private donations from high earners than low earners eases the incentive compatibility constraint for donors and so can raise social welfare. This follows since considering a lower-paid job includes a perception of a drop in public good provision. Second, private donation reduces consumption, easing the resource constraint. This paper explores optimal policy, using first a model with standard preferences and then a model with a warm glow of giving. In addition to showing the conditions for the level of public goods, the paper considers the pattern of optimal subsidization across earnings levels. Analysis of optimal taxation with warm glow preferences is sensitive to the choice of preferences that are relevant for a social welfare evaluation. After considering optimal rules with formulations of social welfare which do and do not include warm glow utility, the paper considers the choice of normative criterion. Like the earlier literature, this paper assumes that organizing private donations is costless while tax collection has a deadweight burden. Since private charitable fundraising is very far from costless, the paper is an exploration of economic mechanisms, not a direct guide to policy.     

Measuring tax efficiency: A tax optimality index

This paper introduces an index of tax optimality that measures the distance of some current tax structure from the optimal tax structure in the presence of public goods. This index is defined on the [0, 1] interval and measures the proportion of the optimal tax rates that will achieve the same welfare outcome as some arbitrarily given initial tax structure. We call this number the Tax Optimality Index. We also show how the basic methodology can be altered to derive a revenue equivalent uniform tax, which measures the tax burden implied by the public sector. A numerical example is used to illustrate the method developed, and extensions of the analysis to handle models with multiple households and nonlinear taxation structures are undertaken.     

Value-added tax and the theory of tax incidence

A value-added tax is examined in a general-equilibrium model of tax-incidence incorporating primary factors and intermediate goods. Production coefficients are variable and demand is elastic. The principal result is that under assumptions of fixed coefficients and inelastic demand which have been commonly employed in the literature, VAT as well as the corporation income tax will be neutral. In the more general setting of this paper, only VAT, applied to every industry at equal rates, will not affect relative factor and commodity prices. Incidence and other economic effects of a partial VAT are also discussed.