Ensaios na teoria da tributação ótima sem assimetria de informação

Abstract

This thesis consists of three essays and studies the optimal tax scheme in different scenarios without information asymmetry. The first essay considers a model of capital taxation where labor income is subject to idiosyncratic risks. The agents are ex-ante identicals, however ex-post heterogeneous to the shocks. The article contributed to the literature of optimal taxation based mainly on the Ramsey model. Furthermore, it allowed lump-sum transfers and additive and multiplicative shocks in labor income. It shows that, for the multiplicative case, positive taxation in capital income does extend to the case where markets are incomplete due to presence of idiosyncratic risk on the labor income. Market incompleteness may, with effect, change individual consumption level. For additive shocks, differently from the Aiyagari model (1995), it was found out that the tax rate on capital income is equal to zero. In the second essay, a Stackelberg game is characterized between heterogeneous families and the government. The government wants to choose an optimal allocation to maximize social welfare. However, it is subject not only to a restriction of resources, but also, it is limited by the actions of the families. Two exercises are presented. The first exercise adresses the trade off between the optimal taxation on labor income and issuance of public debt when the government cannot commit to its future policy. For sufficiently high values of public debt, the government chooses the default. In this case, the model demonstrates that equilibrium for debt is impossible. Agents, therefore, would not be willing to buy debt at any price. The second exercise is applied to the infinite horizon in a recursive model with dividendtaxationandfullcommitment. Themodelhasshownthatifthemarketisbalanced the government will not have to maximize the welfare of the agents. The governments goal will be to keep its revenues to balance its budget. Infinite public debt plans implement the same allocation of competitive equilibrium. The third essay presents a static computable general equilibrium model for the Brazilian economy of 2013, with the objective of finding optimal tax for some products offered by the economic sectors. From this, the level of government revenue was fixed and a grid was built for a combination of products so that some taxes varied positively and others negatively without changing total revenue. The objective is to achieve the neutrality of government revenue, respectingthegovernmentsbudgetconstraintandatthesametimeraisingthelevel of welfare of families, based on this combination of new taxes. In the first simulation, the chosen products vary by supply elasticity. In the second simulation, products with a certain substitutability are chosen for the analysis of taxes variation. It was verified that some products, because they have a greater range of substitutes, are now sensitive to price elasticity of supply, which leads to a drop in demand with the increase in the tax.