This thesis is concerned with the general trade theoretic issue of what explains tariffs. Two possible theories are investigated: (i) the optimum tariff argument where countries exploit their market power to affect world prices, and (ii) the political economy argument, where well-organised interest groups who have a preference for the tariff protection level can influence their governments through lobbying. The main contribution of this thesis is the use of the many-country, two-good trade model, which can be found in the customs union literature, to investigate the importance of the (world) market structure on the welfare effects of tariffs. This model, where a good is exported by more than one country, allows us to examine the welfare effects of tariffs which vary with how the goods are divided initially among the countries. The theory of optimum tariffs and retaliation, usually in the two-country, two-good context, suggests that the country whose endowments of goods are relatively large tends to 'win' a trade war. Still, the analysis in this chapter shows that there is a greater possibility for a country to win even if the country's endowments are relatively small if the world market of its exportable moves closer to the monopolistic market, i.e. there are less countries exporting the same good and/or the world endowment of that good is divided more disproportionately among its exporters. An important feature of the many-country, two-good trade model is that tariffs are strategic complements between countries that have the same trade pattern and are strategic substitutes otherwise. Therefore, two possible trade agreements can be investigated: (i) an agreement between countries whose tariffs are strategic complements, and (ii) an agreement between countries whose tariffs are strategic substitutes. Since these trade agreements imply different sources of gain for a country (gain from an improvement in terms of trade for the former and gain from an increase in volume of trade for the latter), this thesis examines the choice of a country by comparing the welfare implications between the two possibilities. It is found that a country would prefer to have a trade agreement with the country whose endowments of goods are relatively large regardless of the strategic complementarity or substitutability of their tariffs. Finally, this thesis attempts to endogenise the lobby formation by modelling an individual's decision to participate in lobbying prior to the stages of interaction between a government and lobbies studied by Grossman and Helpman (1994). It is found that no one lobbies individually in equilibrium if the total population and/or the fixed cost of lobbying are too large. An incentive that leads individuals to form a lobby is the ability of the group to restrain the individuals' otherwise offsetting lobbying efforts. An interesting result is that, in equilibrium, some individuals might choose to join the lobbies that lobby against their interests to moderate their efforts rather than to join the lobbies that lobby in their favour. This result raises a question whether the standard industry-lobby in the literature might exaggerate the actual lobbying activities.

Orientador : Prof. Dr. Mauricio Vaz Lobo Bittencourt / Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciencias Sociais Aplicadas, Programa de Pós-Graduação em Desenvolvimento Ecônomico. Defesa : Curitiba, 26/02/2016 / Inclui referências : f. 81-85 / Resumo: Esse trabalho compreende dois ensaios: um deles se dedica a avaliar os ganhos de bem-estar obtidos pelos agentes brasileiros durante a redução de tarifa para o setor automobilístico nos mandatos de Collor/Franco, e o outro avalia os efeitos sentidos pelas exportações brasileiras quando são mencionadas ou não em uma investigação antidumping. O primeiro é justificado com base em uma avaliação dos benefícios gerados em um breve período de atípico regime tarifário liberalizante, uma ocasião rara desde que o Brasil optou por industrializar-se via substituição de importações. O segundo ensaio se justifica por uma melhor avaliação acerca dos efeitos gerados pela utilização desse mecanismo de proteção comercial relativamente recente, e nesse caso específico, acerca dos efeitos gerados pelo uso do instrumento antidumping por terceiros contra os exportadores brasileiros no período de 1991 a 1994-07. O primeiro ensaio encontrou ganhos significativos para (consumidores + produtores) de 1991 a 1994/07, considerando uma queda nas tarifas a partir do valor em 1990 (em 2014 BRL 21,442 bilhões). No mais, também foi calculado os ganhos que poderiam ter sido gerados caso as tarifas tivesse caído para zero no mesmo período (em 2014 BRL 191,556 bilhões). No que concerne ao segundo ensaio, foi encontrado um efeito relevante sobre as exportações brasileiras quando o país é citado em uma petição, para ambos os casos em que o processo terminou com aplicação de direito definitivo e os casos terminados com aplicação de direito preliminar somente. Aquele gerou uma forte queda nos anos um e quarto após o início do processo, enquanto este gerou uma forte queda no ano um e uma forte recuperação no ano quatro. No mais, foi encontrada uma possível evidência de desvio de comércio na situação em que o Brasil não foi mencionado no processo, com as exportações brasileiras crescendo. Ainda, foi também encontrado que o setor "metais" foi o setor mais afetado em quantidade pelas investigações, e que esse também foi mais afetado pela redução das exportações brasileiras em comparação com outros setores. Palavras-chave: Análise de bem-estar. Indústria automobilística. Antidumping / Abstract: This work comprises two essays: one of them is dedicated to evaluating the welfare gains Brazilian agents obtained during the Collor/Franco reduction of tariffs for the automobile sector during their mandates, and the other one evaluates the effects Brazilian exports face when they are mentioned or not in an antidumping procedure. The former is justified on the grounds of evaluating the benefits arisen in a brief period of atypical liberalized trade regime, which has been a rare occasion since Brazil opted to industrialize via import substitution. The second one is justified by means of better assessing the effects of this relatively new trade policy, in this specific case, as to the effects of other parties’ use of the policy against Brazilian exporters in a period that spans from 1994 to 2015. The first essay found a significant gain for (consumers + producers) from 1991 to 1994/07, considering a fall in tariffs from 1990’s level of tariffs (in 2014 BRL 21.442 billion). In addition, it was calculated the gains that could have been generated if tariffs had fallen to zero in that very period(in 2014 BRL 191.556 billion). As for the second essay, it was found a relevant effect on Brazilian exports when the country is mentioned in a petition, both for the cases where the process ended with the application of definitive measures and the cases where there was the application of provisional measures. The former case generated a strong fall in years one and four after the beginning of the process, whereas the latter one generated a strong fall in year one and a strong recovery in year four. In addition, it was found a possible evidence of trade diversion in the situation where Brazil was not mentioned in the process, with Brazilian exports rising. Furthermore, it was also found that the "metals" sector was the most affected sector in the amount of cases initiated, and that its exports are more strongly affected by antidumping processes than other sectors. Keywords: Welfare analysis. Automobile industry. Antidumping.