Redistribution with ex-ante unobserved choice

Introducing dynamics to Mirrlees' (1971) optimal taxation model creates a whole new set of issues that are only starting to be investigated in the literature. When choices are made before one's realizing her productivity incentive constraints ought to be defined as a function of more complex strategies than in the static case. 80 far, all work has assumed that these choices are observable and can be contracted upon by the government. Here we investigate choices that : i) are not observed, andj ii) affect preferences conditional Oil the realization of types. In the simplest possible model where a non-trivial filtration is incorporated we show how these two characteristics make it necessary for IC constraints to be defined in terms of strategies rather than pure announcements. Tax prescriptions are derived, and it is shown that they bear some resemblance to classic optimal taxation results. We are able to show that in the most 'natural' cases return on capital ought to be taxed . However, we also show that the uniform taxation prescription of Atkinson and Stiglitz fails to hold, in general.

Essays in corporate risk management

This research investigates the factors that lead Latin American non-financial firms to manage risks using derivatives. The main focus is on currency risk management. With this purpose, this thesis is divided into an introduction and two main chapters, which have been written as stand-alone papers. The first paper describes the results of a survey on derivatives usage and risk management responded by the CFOs of 74 Brazilian non-financial firms listed at the São Paulo Stock Exchange (BOVESPA), and the main evidence found is: i) larger firms are more likely to use financial derivatives; ii) foreign exchange risk is the most managed with derivatives; iii) Brazilian managers are more concerned with legal and institutional aspects in using derivatives, such as the taxation and accounting treatment of these instruments, than with issues related to implementing and maintaining a risk management program using derivatives. The second paper studies the determinants of risk management with derivatives in four Latin American countries (Argentina, Brazil, Chile and Mexico). I investigate not only the decision of whether to use financial derivatives or not, but also the magnitude of risk management, measured by the notional value of outstanding derivatives contracts. This is the first study, to the best of my knowledge, to use derivatives holdings information in emerging markets. The use of a multi-country setting allows the analysis of institutional and economic factors, such as foreign currency indebtedness, the high volatility of exchange rates, the instability of political and institutional framework and the development of financial markets, which are issues of second-order importance in developed markets. The main contribution of the second paper is on the understanding of the relationship among currency derivatives usage, foreign debt and the sensitivity of operational earnings to currency fluctuations in Latin American countries. Unlikely previous findings for US firms, my evidence shows that derivatives held by Latin American firms are capable of producing cash flows comparable to financial expenses and investments, showing that derivatives are key instruments in their risk management strategies. It is also the first work to show strong and robust evidence that firms that benefit from local currency devaluation (e.g. exporters) have a natural currency hedge for foreign debt that allows them to bear higher levels of debt in foreign currency. This implies that firms under this revenue-cost structure require lower levels of hedging with derivatives. The findings also provide evidence that large firms are more likely to use derivatives, but the magnitude of derivatives holdings seems to be unrelated to the size of the firm, consistent with findings for US firms.

Microeconomic instability and children's human capital accumulation: the effects of idiosyncratic shocks to father's income on child labor, school drop-outs and repetition rates in Brazil

This paper evaluates the long-run effects of economic instability. In particular, we study the impact of idiosyncratic shocks to father’s income on children’s human capital accumulation variables such as school drop-outs, repetition rates and domestic and non-domestic labor. Although, the problem of child labor in Brazil has declined greatly during the last decade, the number of children working is still substantial. The low levels of educational attainment in Brazil are also a main cause for concern. The large rotating panel data set used allows for the estimation of the impacts of changes in occupational and income status of fathers on changes in his child’s time allocation circumstances. The empirical analysis is restricted to families with fathers, mothers and at least one child between 10 and 15 years of age in the main Brazilian metropolitan areas during the 1982-1999 period. We perform logistic regressions controlling for child characteristics (gender, age, if he/she is behind in school for age), parents characteristics (grade attainment and income) and time and location variables. The main variables analyzed are dynamic proxies of impulses and responses, namely: shocks to household head’s income and unemployment status, on the one hand and child’s probability of dropping out of school, of repeating a grade and of start working, on the other. The findings suggest that father’s income has a significant positive correlation with child’s dropping out of school and of repeating a grade. The findings do not suggest a significant relationship between a father’s becoming unemployed and a child entering the non-domestic labor market. However, the results demonstrate a significant positive relationship between a father becoming unemployed and a child beginning to work in domestic labor. There was also a positive correlation between father becoming unemployed and a child dropping out and repeating a grade. Both gender and age were highly significant with boys and older children being more likely to work, drop-out and repeat grades.

Simulation -based smoothing and filtering in factor stochastic volatility models : two econometric applications (July-2001)

The past decade has wítenessed a series of (well accepted and defined) financial crises periods in the world economy. Most of these events aI,"e country specific and eventually spreaded out across neighbor countries, with the concept of vicinity extrapolating the geographic maps and entering the contagion maps. Unfortunately, what contagion represents and how to measure it are still unanswered questions. In this article we measure the transmission of shocks by cross-market correlation\ coefficients following Forbes and Rigobon's (2000) notion of shift-contagion,. Our main contribution relies upon the use of traditional factor model techniques combined with stochastic volatility mo deIs to study the dependence among Latin American stock price indexes and the North American indexo More specifically, we concentrate on situations where the factor variances are modeled by a multivariate stochastic volatility structure. From a theoretical perspective, we improve currently available methodology by allowing the factor loadings, in the factor model structure, to have a time-varying structure and to capture changes in the series' weights over time. By doing this, we believe that changes and interventions experienced by those five countries are well accommodated by our models which learns and adapts reasonably fast to those economic and idiosyncratic shocks. We empirically show that the time varying covariance structure can be modeled by one or two common factors and that some sort of contagion is present in most of the series' covariances during periods of economical instability, or crisis. Open issues on real time implementation and natural model comparisons are thoroughly discussed.

Yet another reason to tax goods

When, in a dynamic model, choices by an agent : i) are not observed, and; ii) affect preferences conditional on the realization of types, new and unexpected features come up in Mirrlees’ (1971) optimal taxation frame- work. In the simplest possible model where a non-trivial filtration may be incorporated, we show how these two characteristics make it neces- sary for IC constraints to be defined in terms of strategies rather than pure announcements. Tax prescriptions are derived, and we are able to show that uniform taxation prescription of Atkinson and Stiglitz fails to hold, in general. Clean results regarding capital income taxation are not easy to come about because usual assumption on preferences do not allow for determining which constraints bind at the optimum. However, in the most ’natural’ cases, we show that return on capital ought to be taxed.