本篇論文主要是想探討在2008年全球金融危機發生後，美國與亞洲國家股票市場之間的相關性是否發生明顯的改變。藉由2005年至2012年美國、新加坡、台灣、日本和泰國的股票市場資料，來觀察各國股票市場的相關性是否產生不對稱的現象，首先檢定美國對其他四個國家有無產生蔓延效果，並藉由不同期間的資料來檢定蔓延效果以看出各國之間是否在極端的情況下產生尾端相關性，最後，再使用不同的關聯結構函數配適出最適合資料的模型。 / The main idea of this paper is to show whether or not that stock market between U.S and Asian country has been obviously changed after 2008 financial crisis. For the sake of observing if there is or not occurred inconsistence phenomenon in each country’s stock market, we use the information from U.S、Singapore、Taiwan、Japan and Thailand since 2005 to 2012. First, look in that if U.S has contagion affects to other four countries and, checkup the contagion effects through the information from different period to find the tail dependence in extreme situation. Finally, to dispose a model which is the most suitable for the information by using different Copula functions.

O presente estudo teve como tema principal a volatilidade do mercado acionário brasileiro onde foi analisada, em artigos separados, sua relação com as práticas de governança corporativa e também com relação ao efeito contágio. O primeiro artigo analisou a relação entre a volatilidade da taxa de retorno de empresas brasileiras com as práticas de governança corporativa, sendo realizada uma análise anterior e posterior de sua respectiva adesão e também foi observado na sequência, o comportamento de empresas que migraram de nível. O período analisado foi de 1999 a 2016, sendo restrita a data de adesão de cada empresa. Como métodos estatísticos e econométricos, foram utilizados os modelos autor-regressivos de heterocedasticidade condicional ARCH-GARCH, em especial o modelo auto regressivo de heterocedasticidade condicional exponencial EGARCH e testes de média, t de student. Também foi realizado um teste de robustez, chamado de grupo controle, formado por empresas de mesmo segmento sem adesão as práticas de governança corporativa para assegurar que os resultados obtidos nas analises primárias não estariam sofrendo influencia de variáveis que não foram alvo do estudo. Os resultados comprovaram que existe relação significante entre as práticas de governança corporativa com uma alteração no comportamento da volatilidade do retorno de ações e também que uma mudança de nível na governança corporativa provoca o mesmo efeito. A aplicação do grupo controle corroborou com os resultados iniciais, indicando que as empresas que não optaram pela adesão as práticas de governança corporativa apresentaram um aumento de volatilidade ou um resultado pior do que as empresas com as práticas. O segundo artigo analisou a relação entre a volatilidade do índice IBOVESPA comparado com a volatilidade dos índices acionários dos principais parceiros comerciais do Brasil (Argentina, EUA, China e Europa), através do efeito contágio. O período de análise foi de 2001 a 2016. Como métodos, foram utilizados os modelos EGARCH e Vetor Auto Regressivo (VAR), incluindo dois instrumentos relacionados ao VAR, denominados de analise de decomposição de variância (ADV) e função de resposta ao impulso (FIR). Os resultados encontrados comprovaram a existência do efeito contágio na variável volatilidade do índice acionário, sendo observado com maior intensidade principalmente pela influencia da bolsa europeia e americana. Também foi evidenciado a influência que a bolsa brasileira exerce na bolsa argentina. / This study had as its main theme the volatility of the Brazilian stock market where it was analyzed, in separate articles, its relation with corporate governance practices and also with respect to the contagion effect. The first article analyzed the relationship between the volatility of the rate of return of Brazilian companies and corporate governance practices. An analysis was carried out before and after their respective adherence and the behavior of companies that migrated to the level was also observed. The period analyzed was from 1999 to 2016, being restricted the date of adhesion of each company. As statistical and econometric methods, we used the autoregressive models of conditional heteroscedasticity ARCH- GARCH, especially the autoregressive model of exponential conditional heteroscedasticity EGARCH and mean tests, t of student. We also performed a robustness test, called a control group, formed by companies from the same segment without adherence to corporate governance practices to ensure that the results obtained in the primary analyzes would not be influenced by variables that were not the target of the study. The results showed that there is a significant relationship between corporate governance practices with a change in the behavior of the volatility of stock returns and also that a change in corporate governance level has the same effect. The application of the control group corroborated the initial results, indicating that companies that did not opt for adherence to corporate governance practices showed an increase in volatility or a worse result than companies with practices. The second article analyzed the relationship between the volatility of the IBOVESPA index and the volatility of the stock indices of Brazil's main trading partners (Argentina, USA, China and Europe) through the contagion effect. The analysis period was from 2001 to 2016. The methods used were EGARCH and Vector Regressive Vector (VAR), including two VAR-related instruments, called variance decomposition analysis (ADV) and impulse response function ( FIR). The results showed the existence of the contagion effect in the variable volatility of the stock index, being observed with greater intensity mainly by the influence of the European and American stock exchange. It was also evidenced the influence that the Brazilian stock exchange exercises in the Argentine stock exchange. / Dissertação (Mestrado)

[pt] Com o surgimento dos criptoativos em 2009, iniciado com o Bitcoin, uma nova dinâmica de investimento e de tecnologia emergiu no século XXI com um novo mercado que já chegou a mais de 800 bilhões de dólares em 2018 e conta com mais de 2.000 moedas. Apesar da elevada volatilidade, de vários escândalos de pirâmides, da ausência de regulamentação e da maior utilização como investimento do que em compras de bens e serviços, os criptoativos vêm ganhando seu espaço, em meio às controvérsias, devido a tecnologia disruptiva. Este trabalho tem por objetivo analisar os 50 maiores criptoativos do mercado durante o período de 2015 – 2018 por meio de três ensaios que abordam: (i) a análise e previsão de volatilidade utilizando o MSGARCH (KLAASSEN, 2002), com testes de acurácia (envolvendo funções perda EQM e QLIKE, bem como o MAE, MAPE e o indicador U de Theil); (ii) análise dos fenômenos comportamentais de efeito manada seguindo modificações nas metodologias CSSD (CHRISTIE E HUANG, 1995), CSAD (CHANG, CHENG E KHORANA, 2000) e HS (HWANG E SALMON, 2004), bem como o efeito contágio seguindo modificações nas metodologias do teste FR (FORBES E RIGOBON, 2002) e de testes de comomentos de ordem superior (FRY, MARTIN E TANG, 2010; FRY-MCKIBBIN E HSIAO, 2018); (iii) bem como a análise do fenômeno de feedback trading por meio do modelo seminal de Sentana e Wadhwani (1992). Como principais achados, foi identificado que: (i) há uma forte influência de dois estados de volatilidade; nos criptoativos com maior probabilidade de ocorrência do segundo regime existe uma maior tendência do aparecimento do segundo estado de volatilidade com a subida de preços, onde existe elação ao efeito manada, o modelo CSAD detectou um efeito pouco significativo, e o modelo CSSD detectou um efeito manada forte estatisticamente significativo no movimento de queda de mercado; o modelo HS capturou com sucesso o comportamento de manada e revelou períodos extremos de manada reversa; em relação ao efeito contágio, o teste FR conseguiu captar contágio do Bitcoin em outras moedas em praticamente todos os casos com exceção do Tether Dollar, BITCNY e ECC - que tipicamente possuem controle inflacionário e particularidades das stablecoins; nos modelos de comomentos, os testes indicaram contágio do Bitcoin em relação as moedas analisadas; (iii) em relação ao fenômeno de feedback trading, foi possível captar feedback trade negativo no TETHER e positivo nas moedas BTC, ETH, CSC e ECC, cuja adequação do modelo utilizado foi confirmada posteriormente pelo teste de viés de sinais (ENGLE E NG, 1993), com exceção do TETHER - que contrariou Sentana e Wadhwani (1992) e Shi, Chiang e Liang (2012) ao apontarem que modelos menos parcimoniosos teriam pouca influência na verificação de feedback trading. / [en] With the arise of cryptocurrencies in 2009, started with the Bitcoin, a new dynamic of investment and technology emerged in the 21st century with a new market that has already exceed US 800 billion in 2018 and has more than 2,000 coins. Despite the high volatility, various Ponzi schemes, lack of regulation and the main use as investment than in purchases goods and services, cryptocurrencies have been gaining ground, amid controversy, due to the disruptive technology. The objective of this work is to analyze the 50 largest cryptocurrencies in the market during the period of 2015-2018 by means of three essays that seek to investigate: (i) the volatility analysis and prediction using MSGARCH (KLAASSEN, 2002), with accuracy tests (involving MSE and QLIKE loss functions, as well as MAE, MAPE, and Theil s U indicator); (ii) the analysis of the behavioral phenomena of herd effect following modifications in CSSD (CHRISTIE e HUANG, 1995), CSAD (CHANG, CHENG e KHORANA, 2000) and HS (HWANG e SALMON, 2004) methodologies, as well as the contagion effect following modifications in the methodologies of FR test (FORBES e RIGOBON, 2002) and higher order comoments tests (FRY, MARTIN e TANG, 2010; FRY-MCKIBBIN e HSIAO, 2018); (iii) the analysis of the feedback trading phenomenon through the seminal model of Sentana and Wadhwani (1992). As main findings, it was identified that: (i) there is a strong influence of two volatility states; in the cryptoassets with more probability of occurrence under the second regime, there is a greater tendency of occurrence of the second state of volatility when prices go up, where there is more the volatility - the exception that has been noted only in BTC and ETH, where the first state of volatility is strong when prices go up, with more volatility; there is more accuracy in the forecasting with two volatility states for long term prediction than in short term prediction; (ii) with respect to the herd effect, the CSAD model detected a small herd effect, with little statistical significance, and the CSSD model detected a strong herd effect statistically significant in the down movement of market; the HS model successfully captured herd behavior and revealed extreme periods of reversal in the herd effect; in relation to the contagion effect, the FR test was able to capture Bitcoin s contagion in other currencies in practically all cases except Tether Dollar, BITCNY and ECC - which typically have inflationary control and particularities of stablecoins; in the comoments models, the tests indicated contagion of Bitcoin in relation to the currencies analyzed; (iii) in relation to the feedback trading phenomenon, it was possible to capture negative feedback trading in TETHER and positive in BTC, ETH, CSC and ECC, whose adequacy of the model used was confirmed later by the signal bias test (ENGLE e NG, 1993), with the exception of TETHER - which contradicts Santana and Wadhwani (1992) and Shi, Chiang and Liang (2012) that less parsimonious models would have little influence on feedback trading.

放款的利息收入雖是商業銀行主要之獲利來源, 但借貸行為卻同時使得銀行承受著違約風險。銀行應透過風險管理方法, 計算經濟資本以提列足夠準備來防範預期以及未預期損失。 另外, 若銀行忽略違約行為之間的相關性, 將有可能低估損失的嚴重性。因此, 為了在考量違約相關性下提列經濟資本, 本文由 Merton (1974) 模型出發, 以信用風險因子模型判定放款對象是否違約, 進而決定銀行面對的整體損失為何。 為簡化分析, 本文假設違約損失率 (loss given default) 為 100%。 再者, 為加強相關性, 本文亦將違約傳染性加入因子模型並比較有無傳染性效果時, 模型所計算出的損失孰輕孰重。 而在決定違約與否時, 須利用來自移轉矩陣上的無條件違約機率, 然信評機構所發布之移轉矩陣概遺漏諸多訊息, 依此, 本文以多期連續的移轉矩陣修正之並得到另一不同的無條件違約機率。 最後, 以臺灣的 537 家上市櫃公司作為資產組合, 經由蒙地卡羅模擬得到兩個因子模型的損失分配, 我們發現具有傳染性效果存在時, 預期損失和非預期損失較大且損失分配也較為右偏。 / Despite interest income from loans is a major profit contributor for commercial banks, lending inevitably makes banks bear default risks. For the sake of avoiding expected and unexpected losses, risk management methods ough to be employed by banks to meet the ecomical capital requirement. Besides, loan loss severity may very well be underestimated if the correlation between default events is disregarded. Therefore, in order to calculate economical capital when taking default correlation into account, we start from Merton (1974) model, and identify if loans will be in default via facor models for portfolio credit risk and portfolio losses can then be detemined. To simplify our analysis in this paper, loss given default is assumed to be 100%. To intensify correlation, default contagion is, moreover, introduced to our factor model and we investigate which model results in larger losses as well. When determining default, we have to utilize rating transition matrices to obtain unconditional probability of default. Transition matrices published by credit rating agencies, however, have embedded drawback of insufficient information. We correct this flaw by means of another transition matrix based on continuous-time observations and produce different unconditional probability of default. Through Monte Carlo simulation, loss distributions are calibrated respectively from the two factor models under portfolio of 537 Taiwan listed and OTC companies. We find that expected and unexpected losses are larger and loss distribution is more right-skewed when infectious effects exsit.

本研究探討雷曼兄弟倒閉事件對美國金融機構股價報酬率所帶來的傳染效果。我們的研究結果顯示，持有雷曼兄弟股份的金融機構受到較顯著的影響，而且在股東當中以商業銀行及投資銀行所受到之衝擊最為顯著，而投資銀行受影響之程度又高於商業銀行。我們也發現，金融機構對雷曼兄弟的持股比例愈高，其股價受到雷曼倒閉危機影響之程度亦愈高。此外，一些規模較小的金融機構在一些事件中亦呈現了顯著的反應，顯示在某種程度上，雷曼兄弟危機事件在金融產業當中引發了傳染效果（Contagion effect）。我們的實證結果也顯示，美國政府此次未介入救援雷曼兄弟的做法，被市場解讀為金融機構不再是「太大而不能倒（too-big-to-fail）」。 / We examine the contagion effect of Lehman Brother’s bankruptcy on US financial institutions’ stock returns. Our results show that financial institutions which held Lehman’s shares were affected more significantly. Furthermore, within Lehman’s shareholders, commercial banks and investment banks were affected most significantly, and impacts on investment banks were more significantly than commercial banks. We also find that the higher financial institution’s ownership percentage of Lehman was, the more its stock price was affected. Besides, some smaller financial institutions were also influenced significantly in some events, to some extent, implying a contagion effect in the financial sector. Our empirical results also indicate that the way that US government not to rescue Lehman Brother was perceived by the market that no financial institutions are too-big-to-fail.

This dissertation reports a series of studies on social influences in decision making with wide ranging marketing implications in areas such as gamification initiatives, participative pricing mechanisms, and charity fundraising strategies. The body of this work comprises of three indepth, stand-alone studies. The first study, "Contagion of the Competitive Spirit: The Influence of a Competition on Non-Competitors", investigates the influence of a competition on noncompetitors who do not participate in it but are aware of it. In a series of experimental studies, the study shows that the mere awareness of a competition can affect a non-competitor's performance in similar tasks. These experiments provide confirmatory and process evidence for this contagion effect, showing that it is driven by heightened social comparison motivation due to mere awareness of the competition. In addition, the study finds evidence that the reward level for the competitors could moderate the contagion effect on the non-competitors. The second study, "The Negative Effects of Precommitment on Reciprocal Behaviour: Evidence from a Series of Voluntary Payment Experiments", examines the effects of precommitment on reciprocal behaviour towards a forthcoming benefit. Through a series of experiments in several countries, the study shows that precommitment often weakens reciprocal behaviour. In two field experiments, a laboratory and an online experiment, the study finds consistent evidence that voluntary payment amounts decrease for individuals who are asked to precommit their payment. The results from a final online trust-game experiment support the posited mental-accounting mechanism for the effect. The third study, "Hold-Up Induced by Demand for Fairness: Theory and Experimental Evidence", explores the domain of hold-up and fairness concerns. While recent research suggests that fairness concerns could mitigate hold-up problems, this study proposes a starkly opposite possibility: that fairness concerns can also induce hold-up problems and thus significant inefficiencies. The study reports theoretical analysis and experimental evidence of hold-up in scenarios in which it will not occur if agents are purely self-interested, but could occur if they care about fairness at ex post negotiation.

L’objet de cette thèse est d’étudier dans un contexte de financiarisation des marchés de matières premières, certaines stratégies adoptées par les investisseurs et leurs impacts sur la volatilité et le co-mouvement excessif entre les marchés énergétiques et financiers. Pour ce faire, trois études sont proposées. La première fait appel aux modèles à changement de régime (MS-VAR) appliqués sur un ensemble des produits énergétiques et couvre la période 1992-2017. Les résultats obtenus suggèrent qu’en période de forte volatilité, les agents commerciaux (agents de couverture) jouent un rôle crucial dans la découverte des prix du marché du gaz. Cependant, ces agents de couverture affectent le bon fonctionnement des autres marchés (pétrole, essence, fioul) et amplifient leur volatilité. La deuxième étude traite les modèles GARCH ADCC versus GARCH DCC sur un échantillon de 17 pays et sur la période 1997-2016. Cette étude met en avant l’effet asymétrique des chocs pétroliers sur les corrélations conditionnelles des marchés asiatiques et africains, qui s’expliquent notamment par les activités d’arbitrage et les comportements hétérogènes des investisseurs. La troisième étude porte sur les modèles autorégressifs à retards échelonnés (ARDL) et révèle qu’après la crise financière, et au-delà des fondamentaux macro-économiques et financiers, l’indice de la spéculation excessive explique, aussi bien à long terme qu’à court terme, la corrélation entre le marché pétrolier et les marchés financiers de certains pays. Ceci génère un phénomène de co-mouvement excessif, et donc un effet de financiarisation sur ces marchés. Enfin, nous concluons les éléments suivantes : premièrement, en période de forte volatilité, le marché du gaz constitue une valeur refuge pour les investisseurs financiers ; deuxièmement, le comportement de l’investisseur explique l’effet de co-mouvement excessif entre le marché pétrolier et certains marchés financiers ; troisièmement, ce phénomène de co-mouvement excessif limite les avantages de la diversification internationale des portefeuilles notamment au moment des turbulences financières. / The object of this thesis is to study in a context of financialization of commodity markets, some strategies adopted by investors and their impact on volatility and excess co-movement between energy markets and financial markets. To this end, three studies are proposed. The first study uses the approach VAR with Switching Regime (MS-VAR) applied to energy markets during the period 1992-2017. The results suggest that during high volatility period, commercial agents (hedging agents) play a crucial role in the discovery of gas market prices. However, these agents affect the efficiency of other markets (crude oil, gasoline, heating oil) and amplify their volatilities. The second study employs GARCH ADCC versus GARCH DCC models for a sample of 17 countries and covering the period 1997-2016. This study highlights the asymmetric effect of oil shocks on the conditional correlations of the Asian and African markets, which can be explained in particular by the arbitrage activities and the heterogeneous behavior of investors. The third study focuses on Autoregressive Distributed Lag models (ARDL) and reveals that after the financial crisis, and beyond the macroeconomic and financial fundamentals, the index of excessive speculation, explains in long term as well as in short term, the correlation between oil market and some financial markets. This generates a phenomenon of excess co-movement, and therefore a financializing effect on these markets. Finally, we can conclude that : firstly, during high volatility period, gas market is a safe haven for financial investors ; secondly, the behavior of the investor explains the effect of excess co-movement between the oil market and some financial markets ; thirdly, this phenomenon of excess co-movement limits the benefits of international portfolio diversification especially during financial turbulences.