L'arbitrage des litiges fiscaux entre particuliers et Etats semblait, récemment encore, ne pas aller de soi. Ces dernières années ont cependant vu naître une jurisprudence arbitrale mettant la fiscalité à l'épreuve du droit international des investissements. La présente thèse s'attache à retracer et évaluer ce phénomène, qui soulève de nombreux sujets juridiquement complexes et politiquement délicats.Ces arbitrages sont sous-tendus par une dialectique subtile opposant protection des investisseurs et souveraineté fiscale de l'Etat d'accueil. La poursuite de ces deux objectifs concurrents constitue la trame de questions épineuses. Les arbitres doivent ainsi, par exemple, apprécier la portée réelle des garanties de stabilisation ou d'exemption fiscales accordées à des investisseurs étrangers, ou encore déterminer si une mesure fiscale constitue une expropriation déguisée, une discrimination prohibée ou un traitement injuste ou inéquitable, au sens d'un traité d'investissement.Avant de trancher ces litiges, les arbitres doivent nécessairement examiner si l'Etat a véritablement – et valablement – consenti à ce que l'exercice de ses prérogatives fiscales soit apprécié par une justice « privée », et si les garanties matérielles inscrites aux traités d'investissement s'appliquent aux mesures fiscales.Une vue d'ensemble de ces affaires révèle, d'une part, que la fiscalité s'accommode sans difficulté particulière de la voie arbitrale, celle-ci constituant une méthode fonctionnelle de règlement des litiges fiscaux internationaux, et d'autre part, que les solutions jurisprudentielles sont globalement satisfaisantes, les arbitres sachant prendre en compte les particularités du sujet. / One might not think that tax disputes should ordinarily be susceptible to resolution through arbitration. However, recent years have seen the unfolding of an arbitral jurisprudence that puts taxation to the test of international investment law. The present thesis seeks to give an account of and evaluate this phenomenon, which raises numerous legally complex and politically delicate issues.These arbitrations consist, fundamentally, in balancing the need to protect investors with the respect for the fiscal sovereignty of the host State. The pursuit of these two competing goals lays the ground for inevitably thorny questions. Thus, arbitrators are called upon to examine the validity and reach of stabilization guarantees or of tax exemptions granted to foreign investors, or even to determine if a tax measure amounts to a disguised expropriation, a prohibited discrimination, or inequitable treatment, in the meaning of an investment treaty.Before resolving these issues, arbitrators must ascertain whether the State has really – and validly – consented to submit the exercise of its taxation powers to the scrutiny of a ‘ private ' legal process, and whether the relevant guarantees enshrined in investment treaties apply to the tax measures in question.An analysis of these matters reveals that arbitrators can address questions of tax law without any particular difficulty and that arbitration is a practical method of dealing with these international tax disputes. Moreover, the solutions reached by international arbitral tribunals are, on the whole, satisfying, as arbitrators take into account the particular needs entailed in balancing the public and private interests at stake.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-04-10T11:18:47Z No. of bitstreams: 1 alinebarretodossantos.pdf: 2986654 bytes, checksum: 62b435ad3742f8ebc90101365fb09182 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-04-10T12:02:48Z (GMT) No. of bitstreams: 1 alinebarretodossantos.pdf: 2986654 bytes, checksum: 62b435ad3742f8ebc90101365fb09182 (MD5) / Made available in DSpace on 2018-04-10T12:02:48Z (GMT). No. of bitstreams: 1 alinebarretodossantos.pdf: 2986654 bytes, checksum: 62b435ad3742f8ebc90101365fb09182 (MD5) Previous issue date: 2018-03-09 / A proposta do estudo foi avaliar os efeitos produzidos pela Lei no 13.043/2014 no mercado de empréstimo de ações que impossibilitou, legalmente, a estratégia de “barriga de aluguel“ por agentes desonerados ao obrigar a retenção de Imposto de Renda (IR) de ações objeto de empréstimo independente da condição tributária do tomador. A hipótese é que a estratégia de arbitragem tributária adotada pelos fundos, ao reterem 15% do valor do Juros sobre Capital Próprio (JCP) devido à condição de desoneração, se constituía em uma fonte de restrição a venda a descoberto e, diante do impedimento dessa, empréstimos de ações serão unicamente utilizados em operações de posições vendidas beneficiando os investidores quanto à redução de taxas de empréstimos e aumento de ações disponíveis para negociação. Utilizou-se de dados do mercado de empréstimo e à vista de ações das empresas listadas na B3 referente aos anos de 2014 e 2015 para estimar o efeito médio da lei pelo Método de Diferenças em Diferenças via regressão de Mínimos Quadrados Ordinários robusto. A base de dados do estudo foi construída a partir de dados de acesso público não sendo possível considerar apenas as negociações realizadas pelo fundos. Mesmo diante dessa restrição, os resultados obtidos indicam que o efeito-lei médio foram significativos e condizente com a teoria para as taxas e volumes do mercado de empréstimo, redução e aumento, respectivamente, em 2015, para ações que distribuíram JCP em 2014. Os resultados das regressões sugerem que a Lei no 13.043/2014 produziu efeitos positivos no mercado de empréstimo de ações como um todo devido à redução das taxas que se refletiu no aumento dos volumes negociados. De outro modo, o efeito médio do novo imposto pode ter sido subestimado por incluir todas as negociações e não apenas dos fundos de investimentos. A contribuição do estudo foi analisar o efeito médio do IR sobre JCP de ações em empréstimo, por meio de base de dados construída a partir de informações de acesso público, sob um prisma tributário do empréstimo de ações. / The purpose of the study was to surveyed the effects of Law no 13.043/2014 on the stock market which made impossible the "barriga de aluguel" strategy. This Law imposed a income tax for the stock borrowing for all takers. The hypothesis is that the funds’s tax arbitrage strategy that retained 15% of the Interest of Own Capital (JCP) due the condition relief’s tax was a short selling’s restriction. So, after the Law, the stock lending will only be used for the short selling. The investors will be benefiting regarding the lending rates’s reduction and the increase of available stocks for trading. We used the market data from the companies listed in B3 of 2014 and 2015 to estimate the law’s mean-effect by Differences in Differences with robust least squares regression. The study database was constructed from public access data and it is not possible to consider only the funds’s negotiations. Even under this restriction the results indicate that the law’s mean-effect was significant because the lending-rates was reducted and lending-volumes was increased in 2015 for the stocks that paied JCP in 2014. The regressions’s results suggest that Law no 13.043/2014 had positive effects on the stock lending market due the reduction in lending-rates reflected in the increase in trading volumes. Otherwise the mean-effect of the new tax may have been underestimated because it included all negotiations and not just investment funds. The contribution of the study was to analyze the mean-effect of IR on stocks lendings that paid JCP in 2014, through a database built from public access information, under a tax prism of the stock lending.