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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Avaliação de empresas: uma proposta para investir na BOVESPA

Montes, Eduardo Vilela Vasconcelos 25 February 2005 (has links)
Made available in DSpace on 2010-04-20T20:20:36Z (GMT). No. of bitstreams: 1 136776.pdf: 1359872 bytes, checksum: 41fdde01b9d823cdaaf0f0b1851b8f9e (MD5) Previous issue date: 2005-02-25T00:00:00Z / This study examined empirically the ability to explain the stock return from a set of financial ratios used in valuation processes of traded companies in the BOVESPA. The financial ratios were selected considering criteria of information availability and calculation easiness. Thus, we used the available financial ratios of the Economática software, totalizing nine financial ratios derived from the financial statements accounts, and six market multiples derived from the combination of the financial statements accounts with the firm quotation or value. The results presented low correlations and low values for R 2 . However, financial ratios and their groups can be analyzed and classified according to the absolute information content (simple regressions) and the incremental information content (multiple regressions). The profitability ratios presented the best results for absolute information content and for incremental information content, primarily the ROA and the ROE, followed by the multiple of patrimony, Ppatrim. The capital structure ratio, Exi_Ati, comes in the 3 rd position of absolute information content and the earnings multiples, FVEbitda, FVLucro, Pebitda and Plucro, come in 4 th position. On the other hand, the incremental information content had the earning multiple, Plucro, in 3 rd position and the capital structure ratio in 4 th position. The financial cycle ratios, the sales multiple and the liquidity ratios come in 5 th , 6 th and 7 th positions for absolute information content and weren’t evaluated for the incremental information content due to their low performance. Summing up, the financial ratios and market multiples can and must be used to support the investment decision, but the investor must rely on other valuation methodologies as showed in this study. Obviously, the financial ratios always must be ranked according to their power to explain the stock return. / Este estudo examinou empiricamente a capacidade de explicar o retorno das ações a partir de um conjunto de indicadores utilizados em processos de avaliação de empresas negociadas na BOVESPA. Os indicadores foram selecionados considerando critérios de disponibilidade das informações e facilidade no cálculo. Desta forma, utilizaram-se indicadores disponibilizados pelo software da Economática, totalizando nove indicadores financeiros (derivados das contas dos demonstrativos financeiros), e seis múltiplos de mercado (derivados da combinação das contas dos demonstrativos financeiros com a cotação ou valor da firma). De modo geral, todos os resultados apresentaram baixas correlações e R2 reduzido. Porém, pode-se analisar os indicadores e seus grupos e classifica-los de acordo com seu conteúdo informacional absoluto (regressões simples) e de acordo com seu conteúdo informacional incremental (regressões múltiplas). Os indicadores de rentabilidade apresentaram os melhores resultados tanto para o conteúdo informacional absoluto quanto para o incremental, destacando- se o ROA e o ROE, seguidos pelo múltiplo de patrimônio, Ppatrim. Na 3a posição do conteúdo informacional absoluto, veio o indicador de estrutura de capital, Exi_Ati e na 4a, os múltiplos de lucro, FVEbitda, FVLucro, Pebitda e Plucro. De forma inversa, o conteúdo informacional incremental, teve o múltiplo de lucro, Plucro, na 3a posição e o indicador de estrutura de capital na 4a posição. Os indicadores de ciclo financeiro, o múltiplo de vendas e os indicadores de liquidez vieram na 5a, 6a e 7a posições para o conteúdo informacional absoluto e não foram avaliados para o conteúdo informacional incremental devido a sua baixa performance. Com base nos resultados obtidos, conclui-se que os indicadores financeiros e múltiplos de mercados podem e devem ser usados como suporte à decisão de investir ou não em uma ação, mas, não como forma única de avaliação. Obviamente, devem ser priorizados sempre os indicadores que tem um maior poder em explicar o comportamento do retorno das ações.
92

Comparativo de metodologias de mensuração de VAR para o mercado financeiro brasileiro

Chun, Liu Yuan January 2007 (has links)
Made available in DSpace on 2010-04-20T21:00:18Z (GMT). No. of bitstreams: 3 liuyuanchun.pdf.jpg: 17401 bytes, checksum: f3f99fd1992b2110a49c01ea2b4a795c (MD5) liuyuanchun.pdf: 1060371 bytes, checksum: 3f2e7592f1f950f8abbb037eaa9e522d (MD5) liuyuanchun.pdf.txt: 115026 bytes, checksum: bba135f45d4f79bd49d73017e1c707c1 (MD5) Previous issue date: 2008-01-17T00:00:00Z / Many methodologies to measure market risk have been developed and improved in the last few decades. While some methodologies are non-parametric, others are parametric. Some methodologies are theoretical, while others are more practical. While some methodologies are original, others are hybrid. In this work, we compared methodologies to measure market risk in the Brazilian market. We evaluated non-parametric and parametric methodologies to measure VaR in a fixed income, equities and a mixture between fixed income and equities’ portfolios between 2000 and 2006. Non-parametric methodologies evaluated were: Fixed-Weight Historical Simulation, Fixed-Weight Antithetic Historical Simulation, Exponential Historical Simulation and Scenario Analysis. Parametric methodologies evaluated were: FixedWeight VaR Delta-Normal, Exponential VaR Delta-Normal (EWMA), Fixed-Weight Monte Carlo Simulation and Exponential Monte Carlo Simulation. Based on statistical measures of conservatism, accuracy and efficiency, we compared the methodologies. / Várias metodologias de mensuração de risco de mercado foram desenvolvidas e aprimoradas ao longo das últimas décadas. Enquanto algumas metodologias usam abordagens não-paramétricas, outras usam paramétricas. Algumas metodologias são mais teóricas, enquanto outras são mais práticas, usando recursos computacionais através de simulações. Enquanto algumas metodologias preservam sua originalidade, outras metodologias têm abordagens híbridas, juntando características de 2 ou mais metodologias. Neste trabalho, fizemos uma comparação de metodologias de mensuração de risco de mercado para o mercado financeiro brasileiro. Avaliamos os resultados das metodologias não-paramétricas e paramétricas de mensuração de VaR aplicados em uma carteira de renda fixa, renda variável e renda mista durante o período de 2000 a 2006. As metodologias não-paramétricas avaliadas foram: Simulação Histórica pesos fixos, Simulação Histórica Antitética pesos fixos, Simulação Histórica exponencial e Análise de Cenário. E as metodologias paramétricas avaliadas foram: VaR Delta-Normal pesos fixos, VaR Delta-Normal exponencial (EWMA), Simulação de Monte Carlo pesos fixos e Simulação de Monte Carlo exponencial. A comparação destas metodologias foi feita com base em medidas estatísticas de conservadorismo, precisão e eficiência.
93

[en] METHODOLOGY FOR INCORPORATING THE DEFAULT RISK ON THE RENEWABLE GENERATOR CONTRACTING MODEL IN THE BRAZILIAN ENERGY MARKET / [pt] METODOLOGIA PARA A INCORPORAÇÃO DO RISCO DE INADIMPLÊNCIA NO MODELO DE CONTRATAÇÃO DE GERADORES RENOVÁVEIS NO MERCADO BRASILEIRO DE ENERGIA

ANDREA MICHELI ALZUGUIR 29 June 2015 (has links)
[pt] Nesta dissertação será proposta uma metodologia que contabiliza o risco de inadimplência no mercado, decorrentes de débitos não pagos à câmara de comercialização de energia elétrica (CCEE) nas estratégias de contratação de geradores renováveis. As incertezas relacionadas à geração e ao preço de curto prazo são consideradas através da simulação de cenários exógenos ao modelo como habitual em otimização estocástica. A otimização robusta é empregada através de conjuntos de incerteza poliédricos a fim de modelar a inadimplência do mercado. Dessa maneira, a metodologia proposta se baseia em um modelo matemático híbrido, robusto e estocástico. De forma mais objetiva, um modelo de dois níveis é proposto com tantos problemas de segundo nível quanto o número de cenários considerados para a produção renovável. No primeiro nível, as decisões de contratação são feitas. Em seguida, para cada cenário de geração, o problema de segundo nível encontra a pior inadimplência com base na carteira de contratos encontrados pelo primeiro nível. Para resolver o problema, o modelo de dois níveis é reescrito como um problema linear equivalente de um único nível. O perfil de risco do agente é definido por meio do conhecido valor condicional em risco (conditional value-a-risk), uma medida coerente de risco. Para ilustrar a eficácia do modelo de contratação, são realizados estudos de casos com dados realistas do sistema de energia brasileiro. / [en] In this dissertation we propose a new methodology to account for the market default risk, arising from debts not paid to the market clearing house, in the renewable generators contracting strategy. Renewable generation and spot price uncertainties are considered through exogenous simulated scenarios as customary in stochastic optimization. Robust optimization with polyhedral uncertainty sets is employed to account for the market default. Thus, the proposed methodology is based on a hybrid robust and stochastic mathematical program. More objectively, a bi-level model is proposed with as many second-level problems as the number of scenarios considered for the renewable production. In the first level, contracting decisions are made. Then, for each generation scenario, a second-level problem finds the worst-case default based on the portfolio of contracts found by the first level. To solve the problem, the bi-level model is rewritten as a single-level equivalent linear problem. The agent s risk profile is defined by means of the well-known conditional value-at-risk coherent risk measure. To illustrate the effectiveness of the contracting model, case studies are performed with realistic data from the Brazilian power system.
94

Alternative Methods for Value-at-Risk Estimation : A Study from a Regulatory Perspective Focused on the Swedish Market / Alternativa metoder för beräkning av Value-at-Risk : En studie från ett regelverksperspektiv med fokus på den svenska marknaden

Sjöwall, Fredrik January 2014 (has links)
The importance of sound financial risk management has become increasingly emphasised in recent years, especially with the financial crisis of 2007-08. The Basel Committee sets the international standards and regulations for banks and financial institutions, and in particular under market risk, they prescribe the internal application of the measure Value-at-Risk. However, the most established non-parametric Value-at-Risk model, historical simulation, has been criticised for some of its unrealistic assumptions. This thesis investigates alternative approaches for estimating non-parametric Value-at-Risk, by examining and comparing the capability of three counterbalancing weighting methodologies for historical simulation: an exponentially decreasing time weighting approach, a volatility updating method and, lastly, a more general weighting approach that enables the specification of central moments of a return distribution. With real financial data, the models are evaluated from a performance based perspective, in terms of accuracy and capital efficiency, but also in terms of their regulatory suitability, with a particular focus on the Swedish market. The empirical study shows that the capability of historical simulation is improved significantly, from both performance perspectives, by the implementation of a weighting methodology. Furthermore, the results predominantly indicate that the volatility updating model with a 500-day historical observation window is the most adequate weighting methodology, in all incorporated aspects. The findings of this paper offer significant input both to existing research on Value-at-Risk as well as to the quality of the internal market risk management of banks and financial institutions. / Betydelsen av sund finansiell riskhantering har blivit alltmer betonad på senare år, i synnerhet i och med finanskrisen 2007-08. Baselkommittén fastställer internationella normer och regler för banker och finansiella institutioner, och särskilt under marknadsrisk föreskriver de intern tillämpning av måttet Value-at-Risk. Däremot har den mest etablerade icke-parametriska Value-at-Risk-modellen, historisk simulering, kritiserats för några av dess orealistiska antaganden. Denna avhandling undersöker alternativa metoder för att beräkna icke-parametrisk Value-at‑Risk, genom att granska och jämföra prestationsförmågan hos tre motverkande viktningsmetoder för historisk simulering: en exponentiellt avtagande tidsviktningsteknik, en volatilitetsuppdateringsmetod, och slutligen ett mer generellt tillvägagångssätt för viktning som möjliggör specifikation av en avkastningsfördelnings centralmoment. Modellerna utvärderas med verklig finansiell data ur ett prestationsbaserat perspektiv, utifrån precision och kapitaleffektivitet, men också med avseende på deras lämplighet i förhållande till existerande regelverk, med särskilt fokus på den svenska marknaden. Den empiriska studien visar att prestandan hos historisk simulering förbättras avsevärt, från båda prestationsperspektiven, genom införandet av en viktningsmetod. Dessutom pekar resultaten i huvudsak på att volatilitetsuppdateringsmodellen med ett 500 dagars observationsfönster är den mest användbara viktningsmetoden i alla berörda aspekter. Slutsatserna i denna uppsats bidrar i väsentlig grad både till befintlig forskning om Value-at-Risk, liksom till kvaliteten på bankers och finansiella institutioners interna hantering av marknadsrisk.
95

Sustainability performance and market risk. A study of the banking sector

Särkiniemi, Arvid, Lindman, Oskar January 2023 (has links)
The financial crisis of 2007-2008 highlighted the societal impacts of bank risk-taking. A strong focus on maximizing profits for shareholders combined with a disregard for, and  underestimation of risks led to the downfall of large banks such as Lehman Brothers and multiple other banks getting bailed out by several governments and other banks. The financial crisis spread and impacted all major financial markets across the globe, which highlights the importance of investigating the banking sector from a global perspective. In addition, the influences of corporate social responsibility (CSR) on financial performance and risk have been a growing topic in research as well as in practice. Most banks today invest large amounts of money in CSR activities. The question of how bank spending in CSR activities impacts market risk is important. There are two contradicting views on CSR activities and market risk. The risk mitigation view suggests that banks that focus on stakeholder satisfaction have lower risk due to increased moral capital with stakeholders. The overinvestment view suggests that managers waste scarce resources by overinvesting in CSR activities to further selfish goals and therefore increase risk. This study examines the relationship between sustainability performance (ESG Combined score) and market risk (VaR/CVaR) using a deductive approach. The authors sample 159 banks from 39 countries and all 7 economic regions from 2011-2022. Data is used for testing hypotheses. Results find high ESG Combined Scores are associated with lower VaR/CVaR and results are robust to modifications in VaR/CVaR calculation assumptions. Disaggregation of ESG pillars shows that social pillar scores decrease VaR/CVaR in banks while environmental and governance pillars are insignificant. Results primarily lend support to the risk mitigation view and stakeholder theory stating that firms should focus more on stakeholder satisfaction than maximizing shareholder value. Complementing theories such as legitimacy theory and resources-based view are also considered important theories for explaining the results.
96

Millennials köpbeteende och risktagande på aktiemarknaden : En mer våghalsig generation med annat tänk?

Rosendal, Jens January 2021 (has links)
Millennials har ett starkt avvikande köpbeteende på börsen jämfört med äldre generationer. De har högre riskbenägenhet och är benägna att ta betydligt större risker vid köp av aktier och fonder. Oväntade kursrörelser och en mer oberäknelig börs blir konsekvenser av Millennials oberäkneliga och nyckfulla beteende. Syftet med denna studie var att undersöka Millennials köpbeteende när det kommer till aktier och fonder med fokus på deras risktagande. Studien hade en kvalitativ och deduktiv ansats och ett deskriptivt forskningssyfte. Data samlades in genom fallstudier och semistrukturerade intervjuer på ett selektivt urval av Millennials där frågor baserat på portföljsammansättning, informationsinhämtning, urvalskriterier och riskbenägenhet besvarades. Studiens resultat visade att Millennials sparar på lång sikt, gärna i framtidsbranscher inom teknologi eller medicin. Millennials är vinstsökande och högre risk med potentiellt bättre avkastning föredras över att investera med lägre risk och potentiellt lägre avkastning. Teknologiska framsteg i from av internet och nätmäklare är verktyg Millennials använde sig av vid köp av aktier och fonder. Studien bidrar med kvalitativa data och en djupare förståelse om Millennials och hur samspelet mellan informationsinhämtning, urvalskriterier och risk påverkar Millennials portföljsammansättning. Millennials använder sig av peer reviews och word-of-mouth i stor utsträckning vid köp av aktier men har samtidigt en hög grad av källkritik.
97

Kapitalkostnadsberäkning och investeringsbedömning i några dominerande svenska industri- och fastighetsföretag

Younan, Rudy, Kander, Isak January 2023 (has links)
Bakgrund: Betydelsen av investeringsbedömningen kan inte överbetonas till följd av dess långsiktiga fördelar för företagets giltighet och operativa funktionalitet. Beräkningsmetoder som används för investeringsbedömning bistår med nödvändig kunskap för att underlätta beslutsfattande samt för att skapa sig en tydligare bild över det föreslagna investeringsprojektet. Företag investerar för att upprätthålla sina ekonomiska mål och värderingen av olika investeringsalternativ spelar således en central roll för företagets ekonomiska fortlevnad och utveckling. Kapitalinvesteringar är ofta omfattande och förväntas generera värde på lång sikt, vilket formar företagets ekonomiska fokusområden. Detta belyser viktigheten av en kvalitativ bedömning för olika investeringsalternativ och deras respektive utvecklingsmöjligheter. Syfte: Genom att undersöka användningsområdet för kalkylräntan avser studien att öka kunskapen för sambandet mellan kalkylräntebestämningen och investeringsbedömningen. Detta som ett delsyfte till att undersöka vilka metoder som några svenska industri- och fastighetsföretag använder. Studien avser även vidare att beskriva och analysera företagens investeringskalkylering och kapitalstruktur. Metod: Studien har antagit en kvalitativ forskningsansats med semistrukturerade intervjuer med svenska industri- och fastighetsbolag. Respondenterna valdes ut genom ett målstyrt urval och vidare beskriver metoden hur insamling av det empiriska materialet har gått till. För att besvara studiens problemformulering har det empiriska materialet analyserats med den teoretiska referensramen. Slutsats: Studiens resultat visar tydliga skillnader i relation till den klassiska kapitalteorin och att långsiktiga strategiska investeringar i viss utsträckning tenderar att inkräkta på investeringar som kan generera en högre internränta och således vara mer ekonomiskt lönsam, men som är av mindre strategisk betydelse för bolaget. Detta strider mot teorins förutsättningar om att uppnå en normativt optimal kapitalstruktur. En viktig aspekt av det är att företagen försöker bibehålla en helhetlig bild av investeringarna där förutsättningar för nyutveckling ska uppmärksammas, vilket i regel inte strider mot kapitalteorins antaganden. Men i relation till det kan dock investeringskalkyler endast förse bolag med en begränsa uppfattning av investeringens ekonomiska konsekvenser. / Background: The importance of the investment appraisal cannot be overemphasized as a result of its long-term benefits to the company's validity and operational functionality. Calculation methods used for investment assessment assist with the necessary knowledge to facilitate decision-making, as well as to create a clearer picture of the proposed investment project. Companies invest to maintain their financial goals and the valuation of different investment alternatives thus plays a central role for the company's financial survival and development. Capital investments are often extensive and expected to generate value over the long term, shaping the company's financial focus areas. This highlights the importance of a qualitative assessment for different investment options and their respective development opportunities. Purpose: By examining the area of use for the discount rate, the study intends to increase knowledge of the connection between the discount rate determination and the investment assessment. This as a partial aim to investigate which methods some Swedish industrial and real estate companies use. The study also intends to describe and analyze the companies' investment calculation and capital structure Method: The study has adopted a qualitative research approach with semi-structured interviews with Swedish industrial and property companies. The respondents were selected through a targeted selection and the method further describes the collection of the empirical material. In order to answer the study's problem formulation, the empirical material has been analyzed with the theoretical frame of reference. Conclusion: The results of the study show clear differences in relation to the classic capital theory and that long-term strategic investments to a certain extent tend to encroach on investments that can generate a higher internal rate of return and thus be more financially profitable, but which are of less strategic importance for the company. This goes against the theory's prerequisites for achieving a normatively optimal capital structure. An important aspect of it is that the companies try to maintain a holistic view of the investments where the conditions for new development must be noticed, which as a rule does not contradict the assumptions of the capital theory. However, in relation to that, investment calculations can only provide companies with a limited idea of the financial consequences of the investment.
98

The impact of solvency assessment and management on the short-term insurance industry in South Africa

Van Huyssteen, Johan 11 1900 (has links)
The financial stability of the insurers is important to fulfil its role as a risk transfer mechanism and to protect the purchasers of their products. The European Union is introducing the Solvency II to modernise the current Solvency I regime and to harmonise the different insurance legislation of the members of the European Union. Solvency II introduces an architecture consisting of three pillars, with Pillar I setting the solvency capital requirements, Pillar II the governance and risk management requirements and Pillar III the reporting requirements. The South African Regulator initiated Solvency Assessment and Management for implementation in 2016 to align the South African prudential regulatory framework to meet the Solvency II requirements for third country equivalence. The problem that this study addressed is the possible effect that the introduction of Solvency Assessment and Management may have on the sustainability of short-term insurers in South Africa. The results of a empirical component of the study indicated that small and medium short-term insurers may be negatively impacted due to the costs incurred to implement and comply with the requirements of the new regulatory framework. The effect on the South African short-term industry can be that cover is concentrated among a few large short-term insurers. / Business Management / M. Com. (Business Management)
99

金融控股公司風險管理之實務運作-以J金控公司為例

楊敦仁, Yang, Tun Jen Unknown Date (has links)
自從美國於1999年11月通過金融現代化法案(Gramm-Leach-Bliley Act),排除銀行不得兼營證券及銀行控股公司不得兼營保險業務之規定,准許原銀行控股公司可申請改制為金融控股公司,並以此金融控股公司來經營銀行、證券及保險業務後,我國為尋求國內金融機構能與國際接軌,順應國際金融集團跨業經營之趨勢,遂於2000年通過「金融機構合併法」及「銀行法部分條文修正案」,隨後再於2001年6月26、27日通過包括「金融控股公司法」等之金融六法,期望透過金融機構間之合併與成立金融控股公司,整合銀行、證券、保險、票券等金融相關產業擴大金融機構之規模,透過金融控股公司之跨業平台來滿足客戶之需求,發揮金融資源整合之綜效(Synergy),進而得以提升競爭力與獲利能力。 然而,本國金融控股公司自成立以來發展至今,有關金融控股公司之風險管理之組織、功能與執掌,除了金管會發布之「金融控股公司內部控制及稽核制度實施辦法」之第11條、第12條及第13條,規範金控須訂定適當之風險管理政策與程序,建立獨立有效風險管理機制、應設置獨立之專責風險控管單位,並定期向董事會提出風險控管報告及風險控管機制應包括之內容等原則性規範外,並未有其他較為詳盡之法令或可遵循之規範。 本論文以個案金融控股公司之實務運作為探討,期望可提供國內金融控股公司風險管理之運行之參考,吾人從此次2007及2008次貸風暴所形成之2008世紀金融大海嘯,亦可深知風險管理之重要性,金融機構之風險管理就如同蓋一棟大樓一樣,風險管理之制度與機制是該大樓之鋼樑與鋼柱,每個樓地板是金融機構之各項業務,而串連各樓層之樓梯或電梯為風險管理與各業務部門間之溝通管道,但要大樓不倒,重點在於地基的扎實與穩固,而此大樓之地基即是所謂的「風險管理文化」,透過該地基穩固的支撐每個鋼樑鋼柱及樓地板,才能有效防止並保護大樓能夠屹立不搖。因此,重視風險管理文化之深耕,建立金融機構全員之共識與確實遵循,乃是保有地位與安全之不二法門。
100

Wavelet analysis of financial time series / Analyse en ondelettes des séries temporelles financières

Khalfaoui, Rabeh 23 October 2012 (has links)
Cette thèse traite la contribution des méthodes d'ondelettes sur la modélisation des séries temporelles économiques et financières et se compose de deux parties: une partie univariée et une partie multivariée. Dans la première partie (chapitres 2 et 3), nous adoptons le cas univarié. Premièrement, nous examinons la classe des processus longue mémoire non-stationnaires. Une étude de simulation a été effectuée afin de comparer la performance de certaines méthodes d'estimation semi-paramétrique du paramètre d'intégration fractionnaire. Nous examinons aussi la mémoire longue dans la volatilité en utilisant des modèles FIGARCH pour les données de l'énergie. Les résultats montrent que la méthode d'estimation Exact Local Whittle de Shimotsu et Phillips [2005] est la meilleure méthode de détection de longue mémoire et la volatilité du pétrole exhibe une forte évidence de phénomène de mémoire longue. Ensuite, nous analysons le risque de marché des séries de rendements univariées de marchés boursier, qui est mesurée par le risque systématique (bêta) à différents horizons temporels. Les résultats montrent que le Bêta n'est pas stable, en raison de multi-trading stratégies des investisseurs. Les résultats basés sur l'analyse montrent que le risque mesuré par la VaR est plus concentrée aux plus hautes fréquences. La deuxième partie (chapitres 4 et 5) traite l'estimation de la variance et la corrélation conditionnelle des séries temporelles multivariées. Nous considérons deux classes de séries temporelles: les séries temporelles stationnaires (rendements) et les séries temporelles non-stationnaires (séries en niveaux). / This thesis deals with the contribution of wavelet methods on modeling economic and financial time series and consists of two parts: the univariate time series and multivariate time series. In the first part (chapters 2 and 3), we adopt univariate case. First, we examine the class of non-stationary long memory processes. A simulation study is carried out in order to compare the performance of some semi-parametric estimation methods for fractional differencing parameter. We also examine the long memory in volatility using FIGARCH models to model energy data. Results show that the Exact local Whittle estimation method of Shimotsu and Phillips [2005] is the better one and the oil volatility exhibit strong evidence of long memory. Next, we analyze the market risk of univariate stock market returns which is measured by systematic risk (beta) at different time horizons. Results show that beta is not stable, due to multi-trading strategies of investors. Results based on VaR analysis show that risk is more concentrated at higher frequency. The second part (chapters 4 and 5) deals with estimation of the conditional variance and correlation of multivariate time series. We consider two classes of time series: the stationary time series (returns) and the non-stationary time series (levels). We develop a novel approach, which combines wavelet multi-resolution analysis and multivariate GARCH models, i.e. the wavelet-based multivariate GARCH approach. However, to evaluate the volatility forecasts we compare the performance of several multivariate models using some criteria, such as loss functions, VaR estimation and hedging strategies.

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