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The objective of the thesis is to find out whether expansionary monetary policy creates an upward pressure on asset prices and can thus create asset price bubbles, or more precisely significantly contribute to their creation. In doing so, we test the significance and the sign of coefficient on monetary policy stance indicator as a determinant of real estate and stock prices on 19 OECD countries quarterly panel data since 1980. Further we assess periods of real estate and stock price bubbles and periods of expansionary monetary policy and examine their relationship. The asset price bubbles are assessed on the basis of relevant price indices developments without examining the underlying fundamentals. Based on our results it appears that expansionary monetary policy has a positive effect on real estate prices and can thus contribute to formation of real estate bubbles. The effect on stock prices is ambiguous and mostly statistically insignificant. By examining the relationship between assessed asset price bubbles and periods of expansionary monetary policy we found out that monetary expansion is neither sufficient nor necessary condition for formation of asset price bubbles but also that there is a relatively strong relationship between these events. JEL Classification C23, E43, E52, E58, G12, N10, N20...

Model selection methods and nonparametric estimation of Levy densities are presented. The estimation relies on the properties of Levy processes for small time spans, on the nature of the jumps of the process, and on methods of estimation for spatial Poisson processes. Given a linear space S of possible Levy densities, an asymptotically unbiased estimator for the orthogonal projection of the Levy density onto S is found. It is proved that the expected standard error of the proposed estimator realizes the smallest possible distance between the true Levy density and the linear space S as the frequency of the data increases and as the sampling time period gets longer. Also, we develop data-driven methods to select a model among a collection of models. The method is designed to approximately realize the best trade-off between the error of estimation within the model and the distance between the model and the unknown Levy density. As a result of this approach and of concentration inequalities for Poisson functionals, we obtain Oracles inequalities that guarantee us to reach the best expected error (using projection estimators) up to a constant. Numerical results are presented for the case of histogram estimators and variance Gamma processes. To calibrate parametric models,a nonparametric estimation method with least-squares errors is studied. Comparison with maximum likelihood estimation is provided. On a separate problem, we review the theoretical properties of temepered stable processes, a class of processes with potential great use in Mathematical Finance.

This thesis presents two classes of models of boundedly rational decision makers - one with application to finance and the other to pricing. It consists of three parts. The first part of the thesis investigates the impact of investors' boundedly rational forecasting on asset price bubbles. We present a class of models, called extrapolation-correction models, of boundedly rational investor behavior. That is, the investors in our model, quite reasonably, use data available to them, i.e. past price data, to form forecasts about future prices. We relate the model parameters to various behavioral aspects like investor memory, caution/confidence, and panic. We present the resulting dynamical system model of asset price bubbles and relate the behavior of the dynamical system to the parameters capturing investor forecasting behavior. We show that, depending on the behavioral parameters, the associated dynamical system can converge to the fundamental value, go into predictable price cycles, or go into unpredictable price cycles. In particular, we find that the greater the weight investors' forecasts put on the most recent observations, the greater the tendency for the asset prices to exhibit cycles, forming positive and negative bubbles. We also find that when forecasts are strongly affected by recent prices, the price process becomes chaotic and it becomes increasingly difficult to forecast future prices accurately. The second part of the thesis addresses the question: How do investors make their price forecasts? We present the design of an experiment where investors participate in a virtual asset market run over a computer network. During the course of the experiment, the participants report their price forecasts and enter buy and sell orders. The computer software determines the market clearing prices. Despite full disclosure of the assets' dividends and the fundamental value, the price trajectories in all three experimental sessions exhibited cycles. We calibrated various models, including rational expectations based models and the extrapolation-correction family of models presented in the first part of the thesis. The results indicate that rational expectations hypothesis does not provide an accurate model of forecast formation. Moreover, a simple one-parameter exponential smoothing model is much better at modeling forecast formation, with the extrapolation-correction models making the fit slightly better. The third part of the thesis explores a different aspect of customer rationality - that of customer impatience - and its effect on pricing of product versions. We consider a setting in which impatient customers are faced with frequent product introductions, for example, products like Apple iPhones. This raises the following questions regarding customers: Given the pricing strategy of the firm, what are the optimal buying behaviors of the customers? How does customer buying behavior change in relation to impatience? We consider two settings. In the first setting, the firm offers a trade-in price for existing customers and a higher full price for new customers. In the second setting, the firm offers the same prices to new and existing customers, however there is an introductory full price and a discounted price later in the product cycle. We model the customer's problem in these two settings and characterize their optimal actions as a function of the price parameters. We also analyze the bilevel program for the firm's pricing decisions. We see that in both settings considered there are certain well-defined regions in the price space wherein the firm's optimal decision lies. We also provide some numerical computations to study the behavior of the optimal prices as the cost per unit increases.

Created in 2009, the digital currency of bitcoin is a relatively new phenomenon. During this short period of time, it has however displayed a strong development of both price and trade volume. This has led to increased media attention, but also regulators and researchers have developed an interest. At this moment, the amount of available research is however limited. With a focus on the price volatility of bitcoin and an aim of finding drivers of this volatility, this study is taking a unique position. The research has its basis in the philosophical position of positivism and objectivism. This has shaped the research question as well as the construction of the study. The result is a describing and explaining research with a deductive research approach, a quantitative research method and an archival research strategy. This has in turn stimulated an extensive literature review and information search. Areas of discussion are microstructure theory, the efficient market hypothesis, behavioural finance and informational structures. Due to the limited amount of previous bitcoin research within the area of price volatility, the study has drawn extensively on research performed on more classical assets such as stocks. Nevertheless, when available, bitcoin research has been used as a foundation/reference and an inspiration. Reviews of academic literature and economic theories, as well as public news helped to identify the variables for the empirical study. These variables are; information demand, trade volume, world market index, trend and six specified events, occurring during the chosen sample period and included in the study as dummy variables. The variables are all analysed and included in a GARCH (1,1) model, modified following a similar research by Vlastakis & Markellos (2012) on stocks. This GARCH (1,1) model is then fitted to the bitcoin volatility registered for the sample period and is able thereby able to generate data of if and how the variables affect the bitcoin volatility. The test result suggests that five of the ten variables are significant on a 5 %-level. More specifically it suggests that information demand is a significant variable with a positive influence on the bitcoin volatility, something that corresponds to the literature on information demand and price volatility. This also relates to the events found significant, as they generated bitcoin related information. The significant events of the Cypriot crisis and the failure of the bitcoin exchange MtGox are thus specific examples of how information affects price volatility. Another significant variable is trade volume, which also displays a positive influence on the volatility. The last significant variable turned out to be a constructed positive trend, suggesting that increasing acceptance of bitcoin decreases its volatility.

L’objectif de cette thèse est d’étudier les divers aspects de la crise financière 2007-09. Dans l’ensemble, les deux types d’objectifs sont poursuivis dans cette thèse: le premier objectif est de déchiffrer les liaisons entre les différents marchés boursiers, immobiliers et pétroliers afin d’évaluer les retombées du rendement et de la volatilité. L’accent dans ce champ est mis sur le niveau d’intégration entre les marchés pendant différents périodes de temps y compris la crise. Ce domaine est examiné par le développement de trois essais distincts. Le premier essai examine la déclaration du gouvernement Russe affirmant que ce sont les chocs initiés par les marchés étrangers qui ont été essentiellement responsables de la panique sur leur marché boursier pendant la période Septembre - Octobre 2008. En utilisant l’approche de la contagion financière, les résultats indiquent que le marché boursier Russe est intégré faiblement avec les marchés Américain et Européen ce qui met à l’écart l’affirmation du gouvernement. Les résultats de la comparaison bivariée des marchés montrent que le marché Russe émet un niveau élevé des chocs en affectant la structure de corrélation entre la Russie et les marchés étrangers tandis que l’inverse est vrai dans le cas des retombées de la volatilité. Il est conclu que les gouvernements ne devraient pas utiliser la justification des chocs étrangers qui affectent les marchés locaux pendant la crise globale. Comme dans l’analyse précédente, nous examinons la transmission des chocs et de la volatilité sur les marchés des sociétés d’investissements immobiliers cotées (SIIC). Etant donné que la loi exige des SIIC de consacrer une grande partie de leurs investissements dans les actifs immobiliers, le rôle des SIIC dans la propagation de la crise hypothécaire des subprimes à travers le globe a été évalué. L’analyse préliminaire démontre que pendant la crise tous les marchés possèdent entre eux des liens de causalité dans le sens de Granger. Ce résultat est en accord avec le point de vue largement répandu que les marchés boursiers se comportent de la même manière pendant la crise globale. Ensuite l’intégration entre les SIIC américaines (USREITs) et les SIIC globales et le S&P500 a été examiné. Les résultats indiquent que les SIIC américaines sont faiblement intégrées avec les SIIC globales impliquant un niveau faible des retombées bidirectionnelles du choc et de la volatilité tandis que l’inverse est vrai dans le cas des SIIC américaines (USREITs) - S&P500. Enfin, l’intégration entre le S&P500 et les SIIC globales a été exploré. Les résultats suggèrent une faible intégration entre le S&P500 et les SIIC globales. Les chocs sont essentiellement transmis du S&P500 vers les SIIC globales. D’une manière générale, l’étude amène à la conclusion que ni les SIIC américaines ni le S&P500 ne peuvent pas créer une panique plus grande sur les marchés des SIIC globales pendant la crise. Ces liens faibles indiquent également les avantages de la diversification d’un portefeuille.En étudiant la crise au niveau suivant, nous analysons la relation à court ainsi qu’à long terme entre le prix du pétrole brut et les marchés boursiers pour le Brésil, la Russie, l’Inde et la Chine (BRIC) dans le cadre des modèles structurels contraints. Nos conclusions indiquent que les marchés boursiers du BRIC suivent dans certaine mesure l’hypothèse de l’efficience des marchés comme dans le cas d’un pays importateur du pétrole un choc positif de prix du pétrole entraîne une chute du marché boursier et l’inverse est vrai pour tous les pays exportateurs du pétrole. Les deux comportements importants ont été identifiés qui sont liés au taux d’intérêt à court terme et à la production industrielle. La montée des prix du pétrole engendre l’inflation qui est enrayée par une hausse du taux d’intérêt à court terme. En même temps, la production industrielle a tendance à s’accroître en termes réels au lieu de diminuer vu le choc des prix du pétrole (une hausse des prix du pétrole). Ce résultat peut être imputé à la couverture du risque d’une hausse des prix du pétrole avec la livraison physique. Dès que le contrat de couverture commence à expirer après 30, 90 ou 180 jours l’impact des prix du pétrole commence à réduire la production industrielle. Le deuxième objectif de la thèse est d’étudier l’intervention gouvernementale particulièrement sur les marchés boursiers et dans l’économie en général. D’un point de vue boursier, nous analysons le cas de l’intervention répétée du gouvernement Russe sur ses marchés boursiers nationaux pendant la fin d’année 2008. En utilisant la méthodologie des études d’événements, les résultats sont peu concluants sur l’efficacité de l’intervention gouvernementale pour protéger le marché boursier contre des chocs financiers extérieurs. Ainsi l’étude préconise aux gouvernements de ne pas intervenir pendant la crise des marchés boursiers.En étudiant le cas de l’économie en général, une nouvelle idée a été développée et lancée concernant l’intervention de la banque centrale pour contrecarrer une Bulle des Prix des Actifs (BPA). Nous avons détecté différents problèmes dans la théorie économique concernant l’intervention de la banque centrale sur le marché monétaire en cas d’apparition d’une BPA comme par exemple, - un décalage dans le temps ne peut pas avoir une incidence sur le secteur formant une bulle spéculative tout seul ainsi que l’inadéquation des canaux traditionnels des prêts bancaires. Pour faire face à ces problèmes l’étude fait avancer l’idée d’une intervention réglementaire basée sur certaines suppositions classiques. L’idée implique que contrairement à l’intervention traditionnelle de la politique monétaire la banque centrale devrait imposer aux institutions de crédit des limites d’exposition au risque de crédit pour chaque secteur. Ces limites devraient être imposées une fois que la banque centrale découvre une hausse anormale des prix dans un secteur économique donné. Nos résultats préliminaires suggèrent que l’idée d’une intervention réglementaire a du potentiel de contrecarrer la BPA. / The objective of the dissertation is to study various aspects of financial crisis 2007-09. Overall there are two kinds of objectives that are pursued in this dissertation: the first objective is to decipher the linkages between different stock markets, real estate markets and oil markets in order to assess the return and volatility spillover effects. The focus in this area is on the level of integration among the markets during different periods of time including crisis. This area is investigated through developing three separate essays. The first essay tests the Russian government claim that shocks originating in foreign markets were primarily responsible for its stock market panic during September-October 2008. Using financial contagion framework, the results indicate that the Russian stock market is weakly integrated with the US and European market in turn discarding the government claim. In bivariate market comparison, the results indicate that Russian market emits high level of shocks affecting the correlation structure between Russia and foreign markets while the reverse is true in case of volatility spillover effects. It is concluded that the governments should not use the justification of foreign shocks affecting the local markets during global crisis. Akin to foregoing analysis, we look at the transmission of shock and volatility in the Real Estate Investment Trust (REIT) markets. Since by law REITs are required to invest a large portion of their investments in real estate, the role of REITs in spreading the subprime mortgage crisis across the globe has been assessed. The initial analysis indicates that during crisis all markets are granger causing each other. The result is in compliance with the widely held view that the stock markets behave alike during global crisis. Next the integration between USREITs and global REITs and S&P500 has been examined. The results indicate USREITs is weakly integrated with the global REITs implying low level of bidirectional shock and volatility spillover while the reverse is true in case of USREITs- S&P500. Finally the integration between S&P500 and global REITs has been explored. The results suggest weak integration between S&P500 and global REITs. The shocks are mainly transmitted from S&P500 to global REITs. Over all the study concludes that neither USREITs nor S&P500 can create a wider panic in the global REIT markets during crisis. These weak linkages points towards portfolio diversification benefits as well.Studying the crisis at the next level, we analyze short-run as well as long-run relationship between crude oil price and stock markets for Brazil, Russia, India and China (BRIC) within a constrained structural modeling framework. Our findings indicate that BRIC stock markets to certain extent follow the efficient market hypothesis such that in case of oil importing country a positive oil price shock cause the stock market to fall and the reverse is true for an oil exporting country. Two important behaviors have been identified related to short-run interest rate and industrial production. The rise in oil prices generate inflation which is countered by increase in short-run interest rate. At the same time, industrial production tends to increase in real terms instead of decreasing in view of oil price shock (increase in oil price). The result can be attributed to hedging oil price risk with physical delivery. Once the hedge contract starts expiring after 30, 90 or 180 days the impact of oil price starts reducing the industrial production. The second objective of the dissertation is to study the government intervention specifically in the stock markets and generally in the economy. From stock market perspective, we analyze the case of Russian government repeated intervention in its national stock markets during late 2008. Using event-study methodology the findings indicate weak evidence that government intervention can in fact prevent stock market from external financial shocks. The study strongly recommends that the governments should not intervene during stock market crisis.Studying the case of general economy, a new idea has been developed and floated regarding central bank’s intervention directed to preempt an Asset Price Bubble (APB). The economic theory regarding central bank monetary policy intervention has been found to suffer from various problems in the event an APB occurs, such as, -time lag, -cannot affect bubbled sector alone as well as –irrelevance of traditional bank-lending channel. To deal with these issues the study brings forward the idea of regulatory intervention based on certain text book assumptions. The idea entails that contrary to traditional monetary policy intervention, the central bank should impose credit exposure limits for a particular sector on credit institutions. These limits should be imposed once the central bank finds out the abnormal increase in prices in a given sector of the economy. Our preliminary findings suggest that idea of regulatory intervention has the potential to preempt the APB.

本篇研究旨在探討利率政策對所得分佈不均的關係，利用 Azzimonti, De Francisco, and Quadrini (2014) 的模型加以延伸擴展，並加入土地或資產的價格變動，從而進一步探討中央銀行的低利率政策對企業主與受薪階層的影響。 模型假設簡單將市場參與者分成2大類，分別是企業家與受薪的勞工，藉由此2大類分別的終生效用函數對利率的變動來說明利率政策對所得分配的影響。Joseph E. Stiglitz (2015b) 提及在低利率政策之下將導致信用的膨脹，進而使土地或資產的價值提高，而土地或資產之價格不斷上漲為造成所得分佈不均之重要原因之一，故本篇論文將土地價格變動納入模型加以延伸，並觀察台灣近幾年之現況。 此篇研究發現，在中央銀行的低利率政策之下，有產階層的企業家之財富條件將會愈來愈好，而與之相對的受薪階層的勞工之財富條件將會愈來愈差；而台灣近幾年之數據亦顯示當利率降低之際，代表所得分佈不均的GINI指數隨之上升，與本篇之研究結果相符。 / The objective of this thesis is to testify the relation between interest rate policy and income inequality. We develop a model based on Azzimonti, De Francisco, and Quadrini (2014) and expand the model by considering the change of the land or asset price so as to analyze the impact of low interest rate on the welfare of entrepreneurs and workers, respectively. The model simply divides the agents into two groups, entrepreneurs and workers, and uses their lifetime utility to explain the impact of interest rate policy on income inequality. Joseph E. Stiglitz (2015b) mentioned that low interest rate would expand the credit availability and drive up the land or asset price. The continuous upward trend of land or asset price is one of the important reason causing income inequality. After taking into account the land or asset price on the sensibility of income inequality toward interest rate, this thesis is able to provide a theoretical underpinning of Taiwan’s empirical observation in recent years. We find out that with low interest rate policy, entrepreneurs’ wealth condition is doing better and better while the workers’ wealth is getting worse. Taiwan’s data in the recent years also shows that once the central bank lowering the interest rate GINI index, which represent the income inequality distribution, will rise immediately. This situation is in accord with the thesis.

The thesis analyses and compares the economies of Spain and Ireland in the run up to and during the current economic and financial crisis. Firstly, the focus is on the pre-crisis period since the mid 90's, the causes and extent of the price bubble on the property markets, the caracter of lending boom and the indebtedness of the private sector. The end of the lending boom and conjuncture on the real estate markets in 2006-2007 had strong impact on real economy and the financial sector. Both countries currently pass through a three-level crisis: economic, banking and debt crisis. The aim of the thesis is to examine their causes, evolution and causal links. The paper also illustrates future perspectives of both countries in context of the membership in EMU and possible solutions to their current situation.

La conduite des politiques économiques a été mise en question après le déclenchement de la crise financière en 2007. Cette thèse analyse les faiblesses identifiées dans la réglementation existante avant la crise et propose des pistes d’amélioration. Le premier chapitre s’intéresse à l’existence du canal de la prise de risque en zone euro. Parle biais des mesures de causalité de long terme, nous démontrons que la politique monétaire a une influence sur le niveau de risque financier. Un autre constat tiré de cette analyse concerne l’absence des mesures de risque systémique.Par conséquent, le deuxième chapitre étudie les mesures proposées après la crise pour les institutions financières et les applique aux États membres de la zone euro. A l’aide de ces mesures, les autorités pourront imposer des règles plus strictes aux pays les plus risqués d’un point de vue systémique. Le chapitre trois envisage une première solution visant à atténuer l’effet des décisions monétaires sur le risque. Nous étudions, à travers un modèle DSGE, l’impact de la stratégie de “leaning against the wind” sur les cycles économiques et financiers. Les résultats montrent qu’unetelle approche n’est pas suffisante pour stabiliser l’économie et que des arbitrages entre objectifs apparaissent. Pour cette raison, le dernier chapitre porte plus en détail sur les arbitrages entre objectifs, et propose, comme une deuxième solution, l’intégration des mesures macroprudentielles dans l’analyse. En utilisant un modèle Néo-Keynésien sous forme réduite, nous trouvons que les fonds propres contracycliques aident à réduire la volatilité des cycles, mais que les trade-offs demeurent en cas de chocs financiers. Le rôle de la banque centrale dans le maintien de la stabilité financière s’avère aussi important, puisque l’utilisation du leaning against the wind semble améliorer la volatilité des cycles. / The conduct of economic policy has been called into question after the outbreak of the financial crisis in2007. This thesis analyzes the flaws identified in the regulation enforced before the crisis and offers suggestionsfor improvement. The first chapter focuses on the existence of the risk-taking channel in the Eurozone. Throughmeasures of long-term causality, we demonstrate that monetary policy influences the level of financial risk. Anotherconclusion drawn from this analysis is the absence of systemic risk measures. Therefore, the second chapter analyzesthe measures proposed after the crisis for financial institutions and applies them to members of the Eurozone. Basedon these measures, authorities may impose stricter rules on countries that prove to be systemically risky. Chapterthree considers a first solution to mitigate the effect of monetary policy decisions on risk. We study, through a DSGEmodel, the impact of the "leaning against the wind" strategy on economic and financial cycles. The results show thatthis approach is not sufficient to stabilize the economy and that it gives rise to trade-offs between objectives. For thisreason, the last chapter examines in more detail the trade-offs between objectives, and proposes as second solution,the integration of macroprudential measures in the analysis. Using a reduced form New-Keynesian model, we find thatcountercyclical capital helps to reduce the volatility of cycles, but trade-offs appear in case of financial shocks. Therole of the central bank in maintaining financial stability seems also important, as the use of leaning against the windimproves cycles’ volatility.

本論文嘗試探討總體經濟中的金融資金面因素， 對於資產價格之決定， 以及價格波動程度與基本面訊息揭露的影響。 本論文包含三篇文章。 第一篇的主旨在於本論文認為投資人所面對的資金成本差異， 是一項解釋資產價格過度波動現象不可或缺的因素。 文獻研究既已指出短期資金市場， 資金成本價差可以有效預測實質產出， 則股價與短期資金市場變數之間似乎也應有所關連。 投資人由於期初財富水準不同， 資金充裕者可以同時持有風險性資產和無風險資產， 資金短缺者則可以採取融資方式投資風險性資產。 一般而言， 融資利率應高於無風險利率， 即使投資人訊息同質， 但因為資金成本不同， 投資需求亦不相同。 當投資人之資金成本差異擴大， 造成平均資金成本變動， 即使基本面沒有任何變化， 資產價格仍然會波動， 並且低於完美市場下的均衡價格。 本篇所建立的部分均衡模型， 可以說明資金成本差異對價格波動性的影響， 以及均衡價格的特性。 第二篇討論加入投資人異質訊息的假設， 投資人在受到資金衝擊之下， 資金借貸限制透過對投資人決策行為的影響， 進而對資產流動性及價格揭露訊息的功能產生何種影響。 本論文嘗試藉由個體結構模式(micro-structure model)， 分析市場資金流動性多寡和訊息效率性(information efficiency)的關聯。 體系存在借貸限制是本論文重點之一， 若沒有借貸限制， 資金將無短缺之虞， 資金流動性多寡就不是問題。 資金流動性若不能轉化為信用(credit)， 則無法探討投資人面對資金衝擊與借貸限制， 所決定的投資決策如何進一步影響基本面訊息反映的程度。 本篇模型特色在於每位投資人， 不論是否擁有關於期末給付的私人訊息， 都可能遭受流動性衝擊。 研究發現當市場資金相對寬鬆時， 借貸行為的比例增加， 但訊息揭露程度反而降低。 第三篇嘗試探討理性投資人或雜訊投資人受到借貸限制， 亦即不是所有想借貸的投資人都能取得可貸資金時， 資金環境對長期資產價格偏離基本面價值所產生之助漲助跌作用， 以及資產價格何時出現高估、 何時出現低估的情形。 本論文舉出兩個基本面完全不同但卻有共同理論模型的故事背景(scenarios)， 用意在顯現我們所觀察到的金融市場價格表現可能來自於兩種不同的市場結構， 單就理論模型來看無法區分究竟是哪一個故事背景之下的結果。 提高融資限制可能妨礙了相關訊息融入， 使得價格更偏離基本面而沒有達到阻卻非理性投機交易的目的。 降低融資限制亦可能是使得非理性投機交易更加猖獗， 而不是刺激基本面相關訊息正確反映。 1 導論 2 資金成本與資產價格波動 2.1 研究動機與目的 2.2 模型 2.3 資本市場均衡 2.4 政策意涵 2.5 結論與相關文獻比較 3 資金流動性與訊息揭露 3.1 研究動機與目的 3.2 模型 3.3 均衡解模擬分析 3.4 結論 4 融資限制與價格穩定性 4.1 研究動機與目的 4.2 模型 4.3 資產均衡價格特性分析 4.4 結論