Cette thèse porte sur les choix des investisseurs de long terme en matière de gestion de portefeuille ainsi que sur les primes de risque offertes par le marché financier Français. Les travaux réalisés dans cette thèse se proposent d’apporter un éclairage ainsi que des arguments en faveur des placements à caractère long, risqué et productifs.En matière de gestion de portefeuille, ce travail apporte plusieurs réponses en matière d’allocation d’actifs et de stratégies optimales d’investissement. Tout d’abord, et en se basant sur des indices boursiers actions et obligataires, il s’avère que le marché français est efficient au sens faible et que l’hypothèse de marche aléatoire n’y est pas rejetée. Ce premier résultat implique que les rentabilités anormales que l’on peut mesurer sur ce marché émanent de facteurs de risque à rémunérer et non pas d’anomalies. Ainsi, dans le deuxième article, on démontre une prime de valeur persistante au sein du marché Français sur la période étudiée. Par contre, la prime de taille n’est observable que pour les titre à ratio valeur comptable sur valeur de marché très faibles ou très élevés ainsi que pour les titres ayant une rentabilité cumulée passée élevée. Aussi, investir dans les entreprises à momentum élevé mène toujours à des rentabilités meilleures quelle que soit la taille de l’entreprise considérée. On confirme également que la bonne spécification du portefeuille de marché est sine qua non pour une évaluation correcte des actifs financiers. Dans le troisième article, et dans une optique multi-périodiques de gestion de portefeuille, l’écart-type des rentabilités annualisées des actifs risqués décroit lorsqu’on allonge la période de détention ce qui implique que les gestionnaires de portefeuille tendent à biaiser les allocations vers des actifs plus sûrs et négligent par cela un manque à gagner. Ce travail démontre également que détenir un portefeuille d’actions de petites capitalisations s’avère un placement optimal pour les investisseurs ayant un horizon long. Ces résultats mettent en lumière des règles prudentielles inefficaces du point de vue des assurés d’une part, et, mettent en évidence la nécessité de mesures visant à relancer les marchés pour les petites entreprises et de faciliter leur accès au financement direct d’autre part. / This thesis focuses on long term investments and risk premiums within the French financial market. The results bring evidence supporting placements in long term, risky and productive assets. In terms of portfolio management, this thesis brings several answers regarding the optimal allocation strategies. The first article demonstrates that the French financial market is weak form efficient since we could not reject the random walk hypothesis based on the variance ratio methodology. This first contribution implies that abnormal returns are resulting from risk factors and not from anomalies. Thus, the second article revisits famous asset pricing models and highlights optimal portfolio strategies. We find that value and momentum premiums are persistent in the French market. However, size premium is only observable in extreme book to market and momentum strategies. Moreover, we show that market portfolio choice is sine qua non to models performances and that the latest is surprisingly increasing in times of distress. The third article considers the term structure of risk-return tradeoff. Based on a VAR model, we find that excess annualized standard deviation of stocks excess returns with respect to bonds and bills decreases as we lengthen investment horizon which means that investors may bias their portfolios towards safe assets and neglect additional return. Furthermore, we measured the time diversification effect among stock portfolios by distinguishing small and big capitalizations and prove that it is more profitable to hold small capitalizations than big capitalizations stocks in the long run. These results shed light on inefficient prudential rules from the viewpoint of policyholders on one hand, and, on the other hand, highlight the necessity of implementing measures to revive the markets for small enterprises and facilitate their access to direct financing through the market.

Operações de alta frequência ganharam destaque nos últimos anos, tanto no mercado nacional quanto internacional, e têm atraído a atenção de reguladores, pesquisadores e da mídia. Assim, surgiu a necessidade de estudar o mercado de capitais brasileiro no contexto dos dados em alta frequência. Este estudo preocupa-se em analisar os efeitos dos avanços tecnológicos e novas formas de negociação na qualidade do mercado. Tais pontos são caracterizados pelo HFT. Gomber e Haferkorn (2013) explicam que HFT é um subgrupo das negociações com algoritmos. Os investidores HFTs são caracterizados por negociarem com seu próprio capital, manterem posições por espaços curtos de tempo, pelo alto volume de negociação e por atualizarem as ordens com frequência. A revisão da literatura permitiu delinear o termo e identificar as estratégias adotadas, os impactos positivos e negativos na qualidade de mercado, os riscos advindos da prática e medidas adotadas ou propostas para mitigar esses riscos. A contribuição decorrente das negociações em alta frequência foi analisada empiricamente com ênfase na questão da eficiência informacional do mercado nacional. Para isso, foram utilizados dados intradiários do índice Bovespa, com frequências de observação a partir de 1 minuto. Aplicações do teste de sequência para aleatoriedade e teste de razão de variância de Lo e Mackinlay (1988) evidenciaram um aumento na eficiência do mercado ao longo do período analisado, entre 2007 e 2015, para a frequência de observações de 1 minuto. Foi encontrada relação entre esse ganho em eficiência e o aumento da participação do HFT no mercado. Também foi constatado que o mercado se mostra menos eficiente quando a frequência de observação aumenta e que os ganhos em eficiência são mais acentuados para frequências maiores. Os últimos resultados fortalecem a percepção de que a melhora na eficiência está relacionada diretamente à atuação dos HFTs no mercado, haja vista a característica destes de explorarem ineficiências de preço em frações de segundos. Descreveu-se assim o mercado de capitais nessa era de alta frequência e os impactos do HFT na eficiência de mercado. Tais pontos podem ser colocados como contribuições práticas deste estudo. / High-frequency trading has gained notoriety in recent years and attracted incresing attention among policymakers, researchers and media. This brought about the need for research of high frequency data on brazilian capital market. This study aims to investigate the effects of technological advancements and new forms of trading, specially HFT, on market quality. Gomber and Haferkorn (2013, p. 97) define HFT as a subset of algorithmic trading \"characterized by short holding periods of trading positions, high trading volume, frequent order updates and proprietary trading\". The literature review made it possible to define the term and identify strategies, positive and negative impacts on market quality, risks and ways to mitigate these risks. The contribution arising from HFT was analyzed empirically with an emphasis on price efficiency in the domestic market, using intraday Bovespa index data in different frequencies. Run tests and Lo and Mackinlay (1988) variance ratio tests showed increasing efficiency over the period, between 2007 and 2015, for observations in 1 minute frequency. Relationship between this gain in price efficieny and the growth of HFT market share was found. It was found that the market is less eficiente when higher frequencies are analyzed, and that the efficiency gains are more pronounced for higher frequencies. The last results strengthen the perception that the efficiency gains are directly related to high-frequency trading, given its characteristc of exploring price inefficiencies that last fractions of seconds. The capital market in this high frequency era and the impacts of HFT on market efficiency were described in this study

Les marchés financiers occupent, depuis des décennies, une place importante dans notre société. Pourtant, ils présentent des risques accrus auxquels font face la majorité des institutions financières. Les crises, les krachs, les bulles et les turbulences financières jalonnent l’histoire de ces marchés et les déstabilisent fréquemment. En effet, l’existence des anomalies et des biais psychologiques, allant à l’encontre de l’hypothèse d’efficience, remettent en question la théorie financière et révèlent de façon rigoureuse les inefficacités des mécanismes de gestion financière et de contrôle du risque du marché. Confrontés à ces évolutions, le comité de Bâle II recommande la Value at Risk comme une nouvelle vision réglementaire des risques. Ce processus d’innovation financière, introduite par la banque JP Morgan dans les années 90, a connu une grande reconnaissance en finance, mais elle est aussi sujette à des controverses continuelles. Pour surmonter les limites de la VaR, nous proposons un nouveau cadre d’analyse de la VaR basé sur des processus fractals. Tenant compte des anomalies et des facteurs de risques du marché financier, qui induisent des rendements par nature non-gaussiens, nous introduisons la VaR en fonction du modèle multifractal à changements de régime markovien de Calvet et Fisher. L’approche VaR-MSM qui modélise la volatilité multifractale à différentes fréquences constitue un aperçu différent d’évaluation du risque du marché. En appliquant ce modèle sur l’indice boursier français le CAC 40, les résultats obtenus révèlent que la VaR-MSM a surpassé assez nettement les autres modèles d’évaluation de la VaR. / Financial markets occupy an important place in our society. However, they present increased risks to financial institutions. Crises, crashes, bubbles and financial turbulence often destabilize these markets. Indeed, the existence of different anomalies and psychological bias, going against the hypothesis of efficiency, put into question financial theory and present an inefficiency of financial and risk management. Faced with these effects, Bale II committee recommended Value at risk as a new financial instrument of risk management. Value at Risk, introduced by JP Morgan Bank in the 90, have a great recognition in finance, but it is also a subject of controversy. To overcome the VaR limits, we propose a new framework based on fractal process. Taking into account abnormalities and risk factors of financial markets, which induce non-Gaussian returns, we introduce the VaR with a Markov-switching multifractal model proposed by Calvet and Fisher. The VaR-MSM approach presents multifractal volatility at different frequencies. We apply this model to the France CAC 40 stock market index. The results clearly show the advantages of VaR-MSM compared with other models of VaR evaluation.

WHAT WAS DONE? This study researches the success of several value investment strategies in the stock markets of the United Kingdom and Germany based on nine firm fundamentals that are extracted from listed firms annual financial statements. In this regard, we first examine alternative forecast combination methods in a novel way to utilise fully the financial information at hand. Second, we examine the drivers of investment returns, particularly the role of information uncertainty, for which a new direct measure is developed. Finally, we evaluate the performance of these financial health investment strategies in alternative institutional environments by focusing on the differences between the two markets regarding both their corporate culture and their legal environment. WHY WAS IT DONE? Similar to economics, the discipline of finance is a social science because its observations emanate from economic transactions between humans. Nevertheless, a significant part of the research in this area is undertaken by means that are almost exclusively applied to the natural sciences, such as mathematics or physics. Although the reasons seem manifold, an increased form of scientificity, in conjunction with greater credibility of the research process and results, is deemed to be of primary importance. However, the benchmark for evaluating these research outcomes differs from those used in the natural sciences. From the example of the efficient market hypothesis one can see that alternative research results that cast serious doubt upon efficiency per se are disregarded as aberrations, leading to the assumption that the hypothesis in its entirety is more or less valid. This study assumes that inefficiencies in the stock market do exist for prolonged periods of time and investors are actually able to benefit from them. HOW WAS IT DONE? Secondary financial statement data of listed companies in the United Kingdom and Germany were downloaded from Datastream for the period between 1992 and 2010. A quantitative analysis of the significance of the correlation between groups of firms with similar financial characteristics and their one-year-ahead stock returns was subsequently performed. Various combination methods for differential weighting of individual financial statement items were conducted. The aim was to increase the profitability of the investment strategy. WHAT WAS FOUND? In general, a classification of stocks according to certain internal criteria of financial health is capable of separating future winners from losers and at the same time confirms the results of a previous US study. More specifically, we first show that a wide range of combination methods generate profitable investment strategies whereby especially measures of profitability are the central indicator of a firm s future performance. Secondly, the more complex methods neither consistently nor substantively outperform the simpler methods. Thirdly, information uncertainty does not seem to be the prime driver of the profitability of an investment strategy. Lastly, we show that financial health investment strategies are profitable both in market-oriented, common law settings and in bank-oriented, code law settings.

Aim of this diploma thesis is to provide empirical tests of market efficiency of tennis wagering market. In large dataset, which consists of nearly 47 thousands matches and 225 thousands odds, I am searching for anomalies, which can prove market inefficiency. Potentially profitable and exploitable betting strategies are also examined. Main tools of empirical analysis are linear probability models and logit models. Favorit-longshot bias is present in my data, this finding is consistent with results of other empirical works (Lahvička, 2013; Cain, Law, Peel, 2000). Major contribution of this paper is confirmation of home-away bias, the issue, which was not tested in tennis matches so far. The same holds for chart-bias. I am not able to find profitable wagering rules based on out-of-sample predictions of my models. Simple betting rule, which consists of betting systematically on overwhelming favorites, is derived from historical odds. This strategy yields a profit 0,0094, but it's applicability is very limited.

Antalet genomförda företagsförvärv på aktiemarknaden har ökat genom åren. Företagsförvärv ämnar till att skapa tillväxt och konkurrenskraftighet genom synergier, ökning av marknadsandelar eller via diversifiering. Syftet med studien är att beskriva hur marknaden reagerar vid tillkännagivande av ett företagsförvärv, samt om det finns något samband mellan marknadens reaktion, konjunktur och förvärvsstrategi. Studien undersöker marknadsreaktionen vid tillkännagivandet av ett företagsförvärv för börsnoterade företag på den svenska marknaden under perioden 2010 till 2020. Studien utgår från arbitrageteorin, den effektiva marknadshypotesen, signaleringsteorin och ekonomisk psykologi. Relevanta studier för ämnet lyfts också fram. Studien har tillämpat en kvantitativ statistisk eventstudie som huvudmetodik för att analysera marknadsreaktionen vid förvärvstillkännagivande. För att förklara eventstudiens resultat genomfördes en multipel linjär regressionsanalys, vilken undersökte sambandet mellan marknadens reaktion, konjunktur och förvärvsstrategi. Resultatet från eventstudien visade att den genomsnittliga abnormala avkastningen var högst på eventdagen men genomsnittligt nära noll. För majoriteten av förvärvstillkännagivandena gick det inte att påvisa någon signifikant skillnad i abnormal avkastning. Studien visade att marknaden inte reagerade kraftigare än vad som var förväntat. Vidare visade regressionsanalysen att varken konjunktur eller förvärvsstrategi hade någon signifikant påverkan på abnormal avkastning. Det betyder således att marknadens reaktion inte påverkades av varken rådande konjunktur eller vilken förvärvsstrategi bolaget hade. / The number of completed acquisitions on the stock market has increased over the years. Acquisitions aim to create growth and competitiveness through synergies, increase market shares or through diversification. The purpose of this study is to describe how the market reacts when announcing an acquisition, and whether there is any relation between the market reaction, the economic cycle and the acquisition strategy. This study examines the market reaction when announcing an acquisition, for listed companies on the Swedish stock market during the period 2010 to 2020. This study is based on the arbitrage theory, the effective market hypothesis, the signaling theory, behavioral finance and other relevant studies. This study has applied a quantitative statistical event study as the main methodology to analyz the market reaction when announcing an acquisition. A multiple linear regression analysis was performed, which examined the relationship between the market reaction, the economic cycle and the acquisition strategy. The results from the event study showed that the average abnormal return was greatest on the event day but on average close to zero. For the majority of the acquisition announcements, it was not possible to determine any significant differences in abnormal returns. This study revealed that the market did not react more deviating than expected. Furthermore, the regression analysis indicated that neither the economic cycle nor the acquisition strategy had any significant effect on abnormal returns. Which means that the market reaction was not affected by neither the current economic situation or the companies acquisition strategy.

El presente trabajo comprueba la hipótesis de eficiencia de mercado (EMH) a través de una medida de persistencia temporal conocida como exponente de Hurst. Esta aproximación además de estar relacionada con la dimensión fractal, permite expandir el análisis de la hipótesis de mercado eficiente, propuesta por Eugene Fama en 1970. El cálculo del exponente de Hurst se realiza en base al método de rango reescalado; y se extiende su aplicación a una estimación dinámica entre el periodo 2006-2021. Este indicador sirve como índice de eficiencia de mercado, y se estima para las series de retornos diarios de los mercados de valores del MILA, conformado por Chile, Colombia, México y Perú. Los resultados demuestran que Perú es el mercado menos eficiente, y con mayor número de ciclos de ineficiencia para el periodo calculado. Por otro lado, México resulta ser el único mercado del MILA que estuvo dentro de la región de eficiencia. / The present work tests the market efficiency hypothesis (EMH) through a measure of time persistence known as the Hurst exponent. This approach, in addition to being related to the fractal dimension, allows us to expand the analysis of the efficient market hypothesis proposed by Eugene Fama in 1970. The calculation of the Hurst exponent is carried out based on the rescaled range method; and its application is extended to a dynamic estimation between the 2006-2021 period. This indicator serves as a market efficiency index and is estimated for the series of daily returns of the MILA securities markets, made up of Chile, Colombia, Mexico, and Peru. The results show that Peru is the least efficient market, and with the highest number of inefficiency cycles for the calculated period. On the other hand, Mexico turns out to be the only MILA market which has been in the efficient region. / Trabajo de investigación

Thesis (M.A. Agricultural Management (Agricultural Economics)) -- University of Limpopo, 2022 / Wheat forms part of the most essential grain crop produced in South Africa after maize. In South Africa, most of the wheat produced is used mainly for human consumption while the remaining is used for animal feed and seed. The wheat industry in South Africa is undergoing severe pressure, with drastic decreases in the area planted to wheat production while imports of wheat continued to increase since the year 1997. This has in return affected the performance and competitiveness of the South African wheat industry at the international stage and its ability to produce enough to meet local demand, hence continuous reliance on imports which later affect domestic wheat prices. Regardless of wheat as one of the most essential grain crop produced in South Africa, very little research is done to evaluate the co-movement, magnitude and speed of price transmission from world to domestic wheat market in South Africa. The study intends to analyse the transmission of world wheat prices to the domestic wheat market in South Africa using average weekly prices for wheat for the period between January 2010 and December 2019. The objectives of the study are to determine the level of cointegration or long run relationship between the world wheat prices and the domestic wheat prices in South Africa, and to assess the degree of world wheat price transmission to the domestic wheat prices in South Africa, with the application of the Error Correction Model. While several authors indicted that long run relationship does exist between spatially separated markets, this study also finds evidence of cointegration or long run relationship between world wheat markets and the domestic wheat market in South Africa. The results confirmed this priori expectation, that in a long run world wheat prices are ultimately transmitted to the domestic market in South Africa. The results further indicate that the speed of corrections or adjustments towards equilibrium conditions were established to be fairly low for domestic wheat prices. The study recommends further research with more emphasis on vertical price transmission from wheat to wheat flour and other wheaten products such as bread and cereals. Further recommendation suggested by the study is that government intervention through implementation of Dollar-Based Reference Price and Variable Tariff Formula for wheat must continue with more caution and improved speed for a quicker response, once there is a newly triggered import duty. / Department of Agriculture, Land Reform and Rural Development

Aktiemarknaden uppfattas som effektiv då aktiepriset faller i paritet med utdelningen på ex-dagen. Tidigare studier ger belägg för att aktiepriset faller med mindre än utdelningen. Att aktiepriset faller med mindre än utdelningsbeloppet på ex-dagen utgör ex-dagseffekten och innebär en avvikande avkastning för aktier kring ex-dagen. Ex-dagseffektens existens har genom historien undersökts och det råder delade meningar kring dess uppkomst och existens. Skattehypotesen, kortsiktiga handelshypotesen, mikrostrukturhypotesen och dispositions-effekten är fyra olika förklaringar till ex-dagseffektens uppkomst som ligger till grund för denna studie. Hypoteserna analyseras i samband med tidigare utförda studier och sedan dras slutsatsen att skattehypotesen är den mest uppmärksammade förklaringen till ex-dagseffekten. / The stock market is perceived as efficient under the presumption that stock prices falls in parity with the dividends on the ex-dividend day. Earlier researches establish that stock prices rather falls with less than the amount of the dividend. The phenomen that the stock prices falls with less than the dividend constitutes the ex-div effect and implicate an abnormal return on the ex-dividend day. The existence of the ex-div effect has been examined through the history and there are shared opinions about its origin and existence. The tax hypothesis, the short-term trading hypothesis, the microstructure hypothesis and the disposition effect are four different explanations of the ex-div effect that forms the basis of this study. The hypotheses are analyzed in conjunction with earlier researches and the conclusion of the study is that the tax hypothesis is the most common explanation for the ex-div effect.

This thesis explores various aspects of long memory behaviour in African stock markets (ASMs). First, we examine long memory in both equity returns and volatility using the weak-form version of the efficient market hypothesis (EMH) as a criterion. The results show that these markets (largely) display a predictable component in returns; while evidence of long memory in volatility is mixed. In general, these findings contradict the precepts of the EMH and a variety of remedial policies are suggested. Next, we re-examine evidence of volatility persistence and long memory in light of the potential existence of neglected breaks in the stock return volatility data. Our results indicate that a failure to account for time-variation in the unconditional mean variance can lead to spurious conclusions. Furthermore, a modification of the GARCH model to allow for mean variation is introduced, which, generates improved volatility forecasts for a selection of ASMs. To further evaluate the quality of volatility forecasts we compare the performance of a number of long memory models against a variety of alternatives. The results generally suggest that over short horizons simple statistical models and the short memory GARCH models provide superior forecasts of volatility; while, at longer horizons, we find some evidence in favour of long memory models. However, the various model rankings are shown to be sensitive to the choice of error statistic used to assess the accuracy of the forecasts. Finally, a wide range of volatility forecasting models are evaluated in order to ascertain which method delivers the most accurate value-at-risk (VaR) estimates in the context of Basle risk framework. The results show that both asymmetric and long memory attributes are important considerations in delivering accurate VaR measures.