Les pactes d’actionnaires, conventions adoptées par les protagonistes des affaires internationales, répondent aux attentes des administrateurs et actionnaires quant à la circulation des actions et des parts sociales. Par contre, hors le marché règlementé, la liberté contractuelle accordée à la société – et actionnaires – de recourir à ce type d’arrangement contractuel, se heurte à la réalité légale et jurisprudentielle qui demeure la seule source de droit régissante cette convention. En optant pour la conclusion d’un pacte d’actionnaires, aucune disposition légale, notamment article de droit, ne régit cette convention. Ce contrat reste donc soumis aux règles de droit commun. Cette particularité accorde aux protagonistes une certaine liberté de rédaction, ce qui créé une originalité quant à la forme, au fond et aux effets de l’application du pacte. Reconnu, dans le monde des affaires français – tant par le législateur français que par les praticiens et protagonistes, comme étant une des formes adaptées à la gestion leurs sociétés, le législateur égyptien découvre encore cette forme contractuelle. La mondialisation, culturelle et commerciale, a non seulement permis de rapprocher entre les commerçants afin de trouver des solutions créatives quant à la conclusion des pactes d’actionnaires, mais aussi aux législateurs, autant bien français qu’égyptiens, de trouver des solutions quant aux problématiques qui s’opposent aux praticiens lors de la négociation, la conclusion ou même l’exécution de ces contrats. L’objet de cette étude sera d’examiner les particularités des pactes d’actionnaires dès la phase des négociations, passant par les phases de conclusion et exécution, jusqu’à la phase conflictuelle. Cette étude visera le modèle français, ayant déjà avancé sur ce domaine, en le comparant au modèle égyptien qui commence à se familiariser avec cette pratique. Bien que ces deux exemples demeurent toujours en voie d’évolution, le recours à ce type de contrat révèle des particularités et difficultés lors de son application, ce qui incitera les protagonistes à trouver des modalités novatrices permettant une mise en œuvre plus efficace de ces contrats et répondant à leurs attentes. / The shareholder agreements, considered as the one of the major contracts concluded by and between the actors of the international affairs, meet the expectations of the companies’ directors and shareholders regarding the transfer of stocks and shares. Nevertheless, outside the regulated market, the principle of contractual freedom accorded to the company - and its shareholders - to resort to this type of contractual arrangement, faces both legal and jurisprudential realities, which remains the only source of law governing this agreement.By choosing to undertake a shareholder agreement, no legal provision, including article nor law, governs this type of agreement. This agreement is therefore subject to the dispositions of the applicable general law. This feature gives the parties some freedom on drafting the agreement, which affects the form and content of the contract and produce its effects on the contract’s application. vWhile this agreement is frequently used in the French business practice - both by the French legislature and by practitioners and shareholders, and considered as one of the forms used to manage the companies, the Egyptian legislation is still discovering this contractual management form.The cultural and commercial globalization has not only helped traders to find creative solutions by entering into this agreement, but it has also helps the French and Egyptian legislations to find solutions as to issues that oppose practitioners during the negotiation of the contract, its conclusion or even during its execution.The purpose of this study is to examine the features of the shareholder agreements starting from the negotiations phase, through the conclusion and execution phases, until the conflictual phase. This study will focus on the French model, having already progressed in this area, compared to the Egyptian model that begins to become familiar with this practice. Although these two examples are still in process of evolution, the use of this type of contracts reveals the peculiarities and difficulties in its implementation, which will encourage the parties to find more innovative methods for more effective implementation of these contracts in order to meet their mutual expectations.

Investors constantly seek information that provides an edge over the market. One of the conventional methods is to find factors which can predict asset returns. In this study we improve the Fama and French Five-Factor model with Regime-Switches, student's t distributions and copula dependencies. We also add price momentum as a sixth factor and add a one-day lag to the factors. The Regime-Switches are obtained from a Hidden Markov Model with conditional Student's t distributions. For the return process we use factor data as input, Student's t distributed residuals, and Student's t copula dependencies. To fit the copulas, we develop a novel approach based on the Expectation-Maximisation algorithm. The results are promising as the quantiles for most of the portfolios show a good fit to the theoretical quantiles. Using a sophisticated Stochastic Programming model, we back-test the predictive power over a 26 year period out-of-sample. Furthermore we analyse the performance of different factors during different market regimes.

Diese Dissertation zielt darauf ab, ein besseres Verständnis für Anomalien und Insiderhandel zu schaffen, sowie die Verfügbarkeit von qualitativ hochwertigen Daten für den deutschen Aktienmarkt zu verbessern. Der erste Aufsatz beinhaltet eine verzerrungsfreie Zeitreihe von monatlichen Renditen deutscher Aktien für die Jahre 1954 bis 2013, die auf der Basis stabiler Regeln berechnet und gut dokumentiert ist. Im Weiteren enthält der Aufsatz eine detaillierte Beschreibung des deutschen Aktienmarktes und dessen Besonderheiten, insbesondere im Vergleich zu den USA. Der zweite Aufsatz zeigt am Beispiel des Fama/French Drei-Faktoren-Modells die Probleme auf, die Anbieter und Nutzer von Faktorendaten haben, die sich nicht auf die USA beziehen. Die empirische Analyse von sieben Faktorensets für Deutschland zeigt, dass die Übernahme von Faktormodellen in einen anderen Kapitalmarkt eine komplexe Thematik ist. Der Aufsatz gibt Anregungen für Nutzer und Anbieter von Faktorensets und zeigt, wie die Wahl des Faktorensets das Ergebnis einer Studie beeinflussen kann. Im dritten Aufsatz werden verschiedene zyklische und antizyklische Handelsstrategien hinsichtlich ihrer Performance im deutschen Aktienmarkt untersucht. Von den untersuchten Strategien erscheint nur Momentum konsequent abnormale Renditen zu erzielen, dies auch nach Transaktionskosten. Die vierte Arbeit untersucht öffentlich bekannt gegebene Aktientransaktionen von Insidern börsennotierter deutscher Unternehmen. Der Aufsatz zeigt, dass Insider von TecDAX-Unternehmen und ihre Imitatoren hohe und statistisch signifikante abnormale Renditen erzielen. Insgesamt zeigt die Dissertation, dass methodische Variationen, die Verwendung verschiedener Untersuchungsdesigns, die Datenqualität und die Sorgfalt beim Erstellen von empirischen Analysen zur Beurteilung der Robustheit und der Stabilität der Ergebnisse unerlässlich sind. Der deutsche Aktienmarkt scheint effizienter zu sein als bisherigere Studien typischerweise nahelegen. / This doctoral thesis aims to contribute to a better understanding of stock market anomalies and insider trading as well as to improve the availability of high quality data for the German stock market. The first paper provides a sixty-year time series of monthly returns on German stocks that is constructed on the basis of stable rules, is well documented, includes all return components, and is free of biases. The paper also contains a detailed description of the German stock market, its peculiarities, regulation and differences as compared to the U.S. The second paper uses the Fama/French three-factor model as an example to point out the problems that providers and users of non-U.S factor data sets face. The empirical analysis of seven different factor data sets available for Germany shows that exporting a specific factor model from the U.S. to another capital market is neither an easy nor well-defined task. The paper gives suggestions to users and creators of factor sets and shows how the choice of a factor set affects the result of an empirical study. The third paper provides evidence on how various contrarian, momentum and seasonality strategies perform in the German stock market. Among these strategies, only momentum investing appears to earn persistently non-zero returns, even after transaction costs. The fourth paper studies publicly disclosed stock transactions by insiders of listed German firms. The paper finds that insiders of TecDAX firms earn large and statistically significant abnormal returns net of transaction costs; for DAX insiders they are indistinguishable from zero. Overall, this thesis illustrates that methodological variations, the use of different specifications, data quality and care when preparing empirical analyses is essential in the assessment of the robustness and stability of results. In sum, the German stock market appears to be more efficient than previous studies have typically suggested.

Die vorliegende kumulative Doktorarbeit umfasst drei Arbeiten aus dem Bereich der empirischen Rechnungslegungsforschung. Die erste Arbeit untersucht die Rolle persönlicher Eigenschaften von Rechnungslegungsstandardsetzern bei der Entwicklung der Internationalen Rechnungslegungsstandards IFRS. Sie dokumentiert, dass in den IFRS insgesamt ein Rückgang der Bedeutung von Prinzipien gegenüber Regeln sowie ein Anstieg der Bedeutung des beizulegenden Zeitwerts im Zeitablauf zu verzeichnen sind. Zwischen Änderungen von IFRS-Eigenschaften sowie beruflichen und kulturellen Eigenschaften von Mitgliedern des International Accounting Standards Board (IASB) wird ein Zusammenhang festgestellt. Die zweite Arbeit widmet sich Ursachen und Folgen fehlerhafter Finanzberichterstattung im Rahmen des deutschen Systems der Durchsetzung von Rechnungslegungsregeln. Sie findet systematische Unterschiede in der Unternehmensführung von Unternehmen, bei denen fehlerhafte Finanzberichte festgestellt werden, gegenüber einer Kontrollgruppe. Weitere Ergebnisse lassen die Vermutung zu, dass die Aufdeckung fehlerhafter Finanzberichte Verbesserungen in der unternehmensspezifischen Aufsicht über den Rechnungslegungsprozess auslösen könnte. Die dritte Arbeit nutzt umfangreiche Befragungsergebnisse deutscher Privatanleger zur Untersuchung der Ursachen ihres Unternehmensüberwachungsverhaltens. Demnach üben Anleger, die ein geringeres Vertrauen in andere Anspruchsgruppen eines Unternehmens haben, zugleich eine geringere Unternehmensüberwachung aus. Darüber hinaus dokumentiert die Arbeit, dass Vertrauen und Unternehmensüberwachung in einem Zusammenhang mit dem Ausmaß der Teilnahme am Aktienmarkt und dem Bildungshintergrund der Anleger stehen. / This cumulative doctoral thesis consists of three papers within the field of empirical financial accounting research. The first paper examines the role of personal characteristics of accounting standard setters in the development of the International Financial Reporting Standards (IFRS). It documents that the full set of IFRS exhibited a decrease in the importance of principles relative to rules and an increase in its fair value orientation over time. Changes in IFRS properties are found to be associated with the professional and cultural background of International Accounting Standards Board (IASB) members. The second paper investigates determinants and consequences of erroneous financial reporting under the German financial reporting enforcement regime. The corporate governance of firms detected with erroneous financial reporting is found to differ systematically from that of control firms. Further results suggest that error detection might trigger improvements in firm-level accounting oversight. The third paper uses large-scale survey evidence from German individual investors to explore the determinants of their monitoring behavior. Investors who are less trusting in their fellow stakeholders are found to engage in less monitoring. Furthermore, trust and monitoring are documented to be associated with the stock market exposure and the educational background of investors.

La présente étude a pour objet de montrer que les moyens de la protection des actionnaires minoritaires en droit chinois et en droit français ne sont pas soumis à des critères fondamentalement différents. Dans les sociétés anonymes, les règles juridiques visent à trouver un équilibre des rapports entre les actionnaires majoritaires et minoritaires, ainsi qu’entre les actionnaires et la société ou le groupe de sociétés.C’est l’intérêt social et le principe d’égalité qui guident le législateur et le juge de proposer des solutions convenables.Il importe de noter qu’en droit français, les dispositions sur les responsabilités et les moyens de recours pour les minoritaires sont d’applications faciles qu’en droit chinois. D’ailleurs, la recherche de l’acquisition des sociétés cotées chinoises sous l’angle de la protection des minoritaires, tout à fait différent à l’offre publique en droit français, présente les particularités du marché réglementé chinois et mérite que les investisseurs étrangers découvrent davantage. / The dissertation aimed to point out that the methods of the protection of minority shareholders in Chinese law and in French law are not subject to the different criteria. In company limited by shares, the legal provisions intend to find a balance of relation between majority shareholders and minority shareholders, and between the shareholders and the company or group of company. It is corporate profits and the principal of equality that direct legislators and judges to suggest applicable solutions.It is important to notify that in French law, legal provisions about the responsibility of majority shareholders or company leaders and the ways of resort of minority shareholders provide reference for improvement of Chinese law. Besides, the study of acquisition of chinese listed companies, looked from the angle of the protection of minority shareholders, very different from tender offer in French law, demonstrate the characteristics of Chinese stock market and deserve foreign investors’ enough attention.

In this paper, market participants’ tendency to form investor herds in the stocks listed on Nasdaq First North Growth Market of Sweden is examined for the period from 2018 to 2023. The models used in this study to detect herd behavior in stocks consist of two measures of dispersions, Cross-Sectional Standard Deviation of returns (CSSD) and Cross-Sectional Absolute Deviation of returns (CSAD), which were proposed by Christie and Huang (1995) and Chang, et al. (2000), respectively. An equally-weighted index consisting of all of the stocks that have traded on this market during the period is created and a quantitative analysis is conducted. Evidence showed absence of herd behavior when using both models, as well as when accounting for robustness tests consisting of small, mid-and large cap portfolios. Our results also support the prediction of rational asset pricing models, which suggest that stock return dispersions around the market returns increase during periods of market stress.

已實現投資報酬率與無風險利率之差、被稱為超額報酬，而股票的預期報酬率超過無風險利率的部份則為股票風險溢酬，是許多資產評價模型的重要依據，例如資本資產定價模型。有不同的理論架構解釋說明風險溢酬值，例如；股票風險溢酬的迷思、短期損失的憎惡、生還存留因素和回歸與偏離平均值等等。 研究台灣股市的超額報酬與股票風險溢酬，有助投資大眾和企業理性面對股市的預期報酬和風險，對台股才有合理的期望報酬值。分析1967年迄2003年的台灣金融市場，計算過去37年長期的幾何平均年報酬率，以臺灣證券交易所發行量加權股價指數為台股市場報酬率，已實現台股實質年報酬率為6.71%。無風險報酬率使用第一銀行的一年期定期存款利率，實質台幣存款年利率為3.07%，消費者物價指數年增率則為4.80%。以年資料計算的台股實質超額報酬，算術和幾何值分別為12.48%和3.63%(年)，計算月資料算術平均和幾何平均值分別為0.77%和0.25%(月)。過去37年長期的台股超額報酬現象未較歐美市場的情況更加明顯，也比一般市場的預期報酬率低。 因資料取得的限制、台股的理論超額報酬方面，1991年迄2003年的近十三年來，經固定股利成長模式和盈餘成長模式的兩種計算方式，台股的實質超額報酬分別為 0.6%和-4.3%，此時期台股的投資報酬率比起台幣存款並不突出、且是低超額報酬。同期的已實現的實質超額報酬值；算術平均1.69%和幾何平均-3.35%。評估目前台股風險溢酬，將十分接近過去37年長期歷史資料得到的超額報酬數值，算術年均值為12.48%(年)和0.77%(月)，幾何平均分別為3.63%(年)和0.25%(月)，低風險溢酬是當前台灣股票市場的一般現象。 / The difference between the observed historical investment return and the risk-free interest rate is the excess return. The equity risk premium, ERP is the expected rate of return on the aggregate stock market in excess of the rate of risk-free security. ERP is one of important factor of many asset-pricing models, including Capital Asset Pricing Model, CAPM. There were many theories and factors to explain the equity risk premium; equity premium puzzle, myopic loss aversion, survivorship bias, mean reversion & aversion and etc. Studying the value of Taiwan equity excess return and risk premium is fundamental for investors and institutions evaluating the expected market investment return and risk. Analyzing the data from year 1967 to 2003 for thirty-seven years long holding period, Taiwan Stock Exchange Capitalization Weighted Stock Index as Taiwan stock market return, the realized real return was 6.71%. One-year bank time deposit rate as NT dollars risk-free asset rate and real interest rate was 3.07% and consumer price index, CPI annual growth rate was 4.80%. The historical real yearly excess return was 12.45% for arithmetic mean and 3.63% geometric mean; the historical real monthly excess return was 0.77% for arithmetic mean and 0.25% geometric mean. Taiwan realized equity excess returns were not higher than the returns in the developed countries and were also lower than the market's expectation. Due to the limits of available data, the theoretical equity excess returns that were calculated on two theoretical models; Constant Growth Dividend Discount Model (dividend yield model) and earnings yield model were 0.6% and -4.3% from year 1991 to year 2003. Comparing the same period of historical realized excess returns of 1.69% for arithmetic mean and -3.35% geometric mean, Taiwan stock market returns were not spectacular. The current equity risk premium of Taiwan stock market is low and should be near the level of the long historical realized equity excess return.