Cette thèse étudie l’impact de la réputation des agences de notation sur la perception de leurs annonces par les investisseurs, ainsi que sur leur propre comportement à divulguer des informations précises et ponctuelles. Elle est constituée de quatre chapitres. Dans les premier et second chapitres, nous étudions comment la perception des investisseurs des notations des agences change suite à l’observation d’une erreur de notation. Les résultats montrent que les investisseurs réagissent peu ou pas aux changements d’annonce après avoir observé des notations erronées, ce qui suggère que la mauvaise performance des agences de notation affecte négativement leur réputation. Dans les troisième et quatrième chapitres, nous étudions les déterminants de la ponctualité et de la précision des annonces de notation financière. Il ressort que la réputation de l’agence de notation affecte la qualité des notations. En particulier, plus la réputation est élevée, et plus la note semble surévaluée et non-ponctuelle. / This thesis studies the impact of the reputation of rating agencies on investors’ perception of ratings, and on rating agencies ability to disclose accurate and timely information. It consists of four chapters. In the first and second chapters, we study changes in investors’ perception of rating agencies’ ratings following the observation of rating failures. The results show that investors either ignore or react less to ratings after such failures, which suggests that rating agencies poor performance affects negatively their reputation. In the third and fourth chapters, we study the determinants of ratings timeliness and accuracy disclosed by credit rating agencies. The results suggest that the reputation of the rating agency affects the quality of ratings. In particular, the higher the rating agency s reputation, the less accurate and timely the rating is.

O trabalho apresenta um processo de classificação de risco dos Certificados de Recebíveis Imobiliários (CRIs), quanto à expectativa de perda presente na carteira de créditos imobiliários, objeto de securitização. O texto, primeiramente, descreve o andamento das operações de securitização no Brasil e no mundo, além de aspectos particulares dessas operações. Em seguida, com maior ênfase, são descritas as principais etapas do processo de rating praticado pelas instituições classificadoras, assim como também, são identificados e analisados os riscos presentes nos CRIs. Riscos estes de origem mercadológica, macroeconômica, legal, e também, associados aos atributos dos créditos que compõem a carteira. Vale destacar, que o processo de classificação proposto tem como foco o investidor que compra o título, aplicando-se ainda, apenas aos CRIs lastreados em créditos imobiliários residenciais. Quanto ao processo de classificação em si, este envolve a simulação do fluxo de caixa da operação; a arbitragem de fronteiras de flutuação do comportamento das variáveis de risco manipuladas no cenário de referência; a geração randômica de uma amostra de laboratório, seguida da análise estatística do nível de perda presente na mesma e; enquadramento do resultado da análise estatística em uma matriz classificatória para obtenção da nota de risco dos CRIs. Portanto, ao fim do trabalho terão sido apresentados procedimentos que se entendem como válidos à análise da perda potencial de carteiras de créditos imobiliários residenciais, além de recomendações e orientações quanto a sua real aplicabilidade no mercado brasileiro. / The work presents a classification process of risk of Mortgage-Backed Securities (MBS) in relation to the loss expectation in the housing loans portfolio that is object of securitization. Firstly, it is described how the operations of securitization are accomplished in Brazil and in the world, and beyond it is showed particular aspects of these operations. After that, it is emphasized the main stages of the risk classification process carried out by rating agencies, as well as are identified and analyzed the risks in the MBS. Those risks arise from areas as marketing, macroeconomics, legal origins, and also they are associated with the credits attributes that comprise the portfolio. It is important to consider that the risk classification process focus on the investor who purchases the stock quotes and it is applied only to the MBS collateralized in housing loans. How much to the process of classification in itself, this involves the simulation of the cash flow of the securitization operation for certain expected scene; the arbitration of borders of fluctuation for each variable of risk manipulated in the reference scene; use of laboratory sample, generated by the random method, for analysis statistics of the level of present loss in the same and; framing of the result of the analysis statistics in a matrix of classification to obtain the note of risk of the MBS. As main conclusions, some procedures are presented that enable the analysis of the portfolio potential loss of residential home loans, beyond recommendations and orientations in regard to its real applicability in the Brazilian market.

O trabalho apresenta um processo de classificação de risco dos Certificados de Recebíveis Imobiliários (CRIs), quanto à expectativa de perda presente na carteira de créditos imobiliários, objeto de securitização. O texto, primeiramente, descreve o andamento das operações de securitização no Brasil e no mundo, além de aspectos particulares dessas operações. Em seguida, com maior ênfase, são descritas as principais etapas do processo de rating praticado pelas instituições classificadoras, assim como também, são identificados e analisados os riscos presentes nos CRIs. Riscos estes de origem mercadológica, macroeconômica, legal, e também, associados aos atributos dos créditos que compõem a carteira. Vale destacar, que o processo de classificação proposto tem como foco o investidor que compra o título, aplicando-se ainda, apenas aos CRIs lastreados em créditos imobiliários residenciais. Quanto ao processo de classificação em si, este envolve a simulação do fluxo de caixa da operação; a arbitragem de fronteiras de flutuação do comportamento das variáveis de risco manipuladas no cenário de referência; a geração randômica de uma amostra de laboratório, seguida da análise estatística do nível de perda presente na mesma e; enquadramento do resultado da análise estatística em uma matriz classificatória para obtenção da nota de risco dos CRIs. Portanto, ao fim do trabalho terão sido apresentados procedimentos que se entendem como válidos à análise da perda potencial de carteiras de créditos imobiliários residenciais, além de recomendações e orientações quanto a sua real aplicabilidade no mercado brasileiro. / The work presents a classification process of risk of Mortgage-Backed Securities (MBS) in relation to the loss expectation in the housing loans portfolio that is object of securitization. Firstly, it is described how the operations of securitization are accomplished in Brazil and in the world, and beyond it is showed particular aspects of these operations. After that, it is emphasized the main stages of the risk classification process carried out by rating agencies, as well as are identified and analyzed the risks in the MBS. Those risks arise from areas as marketing, macroeconomics, legal origins, and also they are associated with the credits attributes that comprise the portfolio. It is important to consider that the risk classification process focus on the investor who purchases the stock quotes and it is applied only to the MBS collateralized in housing loans. How much to the process of classification in itself, this involves the simulation of the cash flow of the securitization operation for certain expected scene; the arbitration of borders of fluctuation for each variable of risk manipulated in the reference scene; use of laboratory sample, generated by the random method, for analysis statistics of the level of present loss in the same and; framing of the result of the analysis statistics in a matrix of classification to obtain the note of risk of the MBS. As main conclusions, some procedures are presented that enable the analysis of the portfolio potential loss of residential home loans, beyond recommendations and orientations in regard to its real applicability in the Brazilian market.

Charakteristika ratingu. Dělení a druhy ratingu (rating emise × rating emitenta; dlouhodobý rating × krátkodobý rating; mezinárodní rating × lokální rating). Obecné požadavky kladené na rating. Proces tvorby ratingu. Vyžádaný rating. Nevyžádaný rating. Ratingový proces na bázi volně přístupných informací. Uplatňované ratingové systémy. Ratingová kriteria. Využití a interpretace ratingové známky. Funkce ratingu. Rating v souvislosti s BASEL II. Rating v souvislosti s hospodářskými krizemi.

The dissertation deals with rating and non-financial factors that form its important part. Rating described in the thesis shall be understood as credit rating, i.e. as an instrument that helps to asses creditworthiness of a company and its future prospects. Typical credit rating is based on an assessment of financial and non-financial factors of a company. Whereas financial factors are widely accepted as inputs of the assessment, the role of non-financial factors remains ambiguous. We have therefore formed a hypothesis that non-financial factors significantly improve the predictive power of rating with the aim to disperse doubts about usefulness of non-financial factors in credit rating assessments.

[pt] O rating soberano pode ser definido como uma nota dada pelas agências de risco às obrigações do governo central de um país. Apesar do primeiro rating atribuído ao país datar de 1986, percebe-se que sua importância cresceu muito a partir de 1994, com a emissão dos brady bonds. Em teoria, as agências de ratings teriam o papel de antever acontecimentos no mercado, e conseqüentemente, seriam suas análises que influenciariam o comportamento dos mesmos; no entanto, severas críticas vêm sendo feitas no sentido de que elas apenas reagem a acontecimentos já amplamente conhecidos. Este trabalho tem, portanto, o objetivo de analisar o impacto das avaliações de risco do país emitidas por estas agências sobre o principal título da dívida externa brasileira, o c-bond. Para avaliar estes impactos, foi analisado o comportamento do spread do c-bond em períodos anteriores e posteriores às divulgações das análises destas agências. O estudo indicou que os ratings soberanos influenciam as cotações do c-bond, sendo os impactos de suas alterações mais significativas para os casos de downgrade ou rebaixamentos das notas soberanas do país. / [en] Sovereign rating can be defined as an assessment of the relative likelihood that a Government will default on its obligations. Although the first rating assigned to Brazil dates from 1986, the importance of sovereign rating increased as from 1994, by which time brady bonds were issued and begun to be actively traded. In theory, the role of credit rating would be to add new information to the market, and therefore, their analyses would influence market behaviour; however, several financial market observers have criticized them for just reacting to completely available information. This study therefore analyses the impacts of sovereign rating changes announcements on c-bond spreads. We analysed how c-bond spreads respond to the agencies´ announcements of changes in their sovereign risk assessments and our analyses indicate that the ratings changes do influence c-bond spreads, most significantly in downgrades events.

Zugl.: Göttingen, Universiẗat, Diss., 2007.

published_or_final_version / Education / Master / Master of Education

The democratic South Africa’s dual challenge in overcoming its own divisive history as well as addressing global economic imperatives, has led to transformations in education. Policy production thus takes place in an atmosphere infused by economic, political, social and cultural effects of globalization. Embedded within the wave of curriculum reform, are new forms of learner assessment which have shifted from being largely norm-based and summative to one which is formative, standards- based and continuous. The new discourse on assessment requires a ‘paradigm shift’ for most teachers implementing the new assessment policy. Although education policy reforms in schools challenge teachers’ existing practices and increases teachers’ work load, they seldom give due attention to teachers’ identities. My research raises questions about the political rationalities that have informed policies on a new conception of the ideal teacher as assessor and how these political rationalities have intersected with the individual lives and identities of teachers. This study investigates at a micro-level, the workings of how teachers govern themselves in their work and in general as human beings. The constitution of teacher identity through discourses and discursive practices of the assessment reform is central to the argument of this thesis which is guided by the following critical question: Within the historical context of the current wave of curriculum reform in South Africa, how is teacher identity constituted in the discourses and practices of assessment reform? Data was obtained from ten teacher participants through interviews, classroom observations and document evidence. Using the biographical / life history approach and teachers’ narratives of self, I explore patterns by which experiential and emotional contexts, feelings, images and memories are organized to form the teachers’ identity. My analytical strategy draws from the work of Foucault (1954-1984), Giddens (1991), Wenger (1998), Bourdieu (1977), Frankl (1984), Laclau and Mouffe (1985), Maslow (1943) as well as other scholars. / Thesis (Ph.D.) - University of KwaZulu-Natal, Durban, 2009.

Reputation systems have the potential of improving the quality of on-line markets by identifying fraudulent users and subsequently dealing with these users can be prevented. The behaviour of participants involved in e-commerce can be recorded and then this information made available to potential transaction partners to make decisions to choose a suitable counterpart. Unfortunately current reputation systems suffer from various vulnerabilities. Solutions for many of these problems will be discussed. One of the major threats is that of unfair feedback. A large number of negative or positive feedbacks could be submitted to a particular user with the aim to either downgrade or upgrade the user's reputation. As a result the produced reputation does not reflect the user's true trustworthiness. To overcome this threat a variation of Bayesian Reputation system is proposed. The proposed scheme is based on the subjective logic framework proposed Josang et al. [65]. The impact of unfair feedback is countered through some systematic approaches proposed in the scheme. Lack of anonymity for participants leads to reluctance to provide negative feedback. A novel solution for anonymity of feedback providers is proposed to allow participants to provide negative feedback when appropriate without fear of retaliation. The solution is based on several primitive cryptographic mechanisms; e-cash, designated verifier proof and knowledge proof. In some settings it is desirable for the reputation owner to control the distribution of its own reputation and to disclose this at its discretion to the intended parties. To realize this, a solution based on a certificate mechanism is proposed. This solution allows the reputation owner to keep the certificate and to distribute its reputation while not being able to alter that information without detection. The proposed solutions cater for two modes of reputation systems: centralised and decentralised. The provision of an off-line reputation system is discussed by proposing a new solution using certificates. This is achieved through the delegation concept and a variant of digital signature schemes known as proxy signatures. The thesis presents a security architecture of reputation systems which consists of different elements to safeguard reputation systems from malicious activities. Elements incorporated into this architecture include privacy, verifiability and availability. The architecture also introduces Bayesian approach to counter security threat posed by reputation systems. This means the proposed security architecture in the thesis is a combination of two prominent approaches, namely, Bayesian and cryptographic, to provide security for reputation systems. The proposed security architecture can be used as a basic framework for further development in identifying and incorporating required elements so that a total security solution for reputation systems can be achieved.