This study shows that managers of short-term insurers may improve their financial results if they can identify and manage the factors that are critical to their financial results. The development and application of the concept of critical success factors are therefore used as a basis for this study. The study reviews the functions performed by short-term insurers, focusing on the effect these functions have on their cash flows. Selection and pricing of risk are discussed in detail. The underwriting cycle in South Africa, and several possible causes of the cycle are investigated. Reinsurance, claims handling and rilanagement expenses are important components of the cash flows of short-term insurers and are therefore examined in detail. The optimum risk level at various combinations of underwriting and investment income is empirically tested, using the financial results of several insurers. The study investigates different approaches to the measurement of financial success of insurers, and the return on shareholders' funds is found to provide the fairest and most reliable method. Empirical comparisons are made on the financial results of the insurers that participated in the study to distinguish between those that are financially successful and those that are not. To discover what the industry consider to be their critical financial success factors, a postal survey was done of key decision makers in the South African short-term insurance industry. Respondents identified several success factors, but did not include some success factors discovered during the review of the literature. Respondents apparently experienced difficulty in separating strategic issues from operational ones. The survey revealed that the pricing of risk is problematic for short-term insurers. The importance of the investment function is also underestimated by the industry. The study concludes that the combined systematic risk of the investment and underwriting portfolios is a critical success factor, along with the capital base of the insurer, the ability of the insurer to use the leverage provided by using policyholders' funds as free reserves and the size and direction of an insurer's cash flows. / Business Management / D. Com (Business Management)

Der erste Artikel liefert Beweise dafür, dass ein Liquiditätsschock bei geschlossenen Fonds zu einer Liquiditätsverschlechterung bei offenen Fonds führen kann. Unsere Ergebnisse zeigen, dass Aktien von geschlossenen Fonds, die aufgrund eines Marktversagens notverkauft wurden, temporär im Preis sinken. Offene Fonds, die viele der betroffenen Aktien halten, erleiden daraufhin einen Kapitalabfluss, der weitere Notverkäufe bedingt. Dies unterstreicht die Ansteckungsgefahr zwischen den beiden Finanzmärkten. Der zweite Artikel untersucht, ob Fonds, die mit Staatsanleihen handeln, ihr Risiko durch den Wertpapierverleih erhöhen, indem sie die hierbei erhaltenen Sicherheiten risikoreich reinvestieren. Hiermit konsistent finden wir, dass die Returnvolatilität von Fonds ansteigt, je mehr Wertpapiere verliehen werden. Diese Korrelation ist nur evident, wenn der für den Wertpapierverleih verantwortliche Agent bereits in der Vergangenheit solch eine Strategie praktiziert hat. Sie verschwindet hingegen, wenn der Agent Sicherheiten nicht risikoreich reinvestieren kann. Im dritten Artikel stellen wir ein neues Maß vor, mit dem sich die Handelsaktivität von Fonds drei Tage vor den Geschäftsberichten untersuchen lässt. Stark handelnde Fonds halten bei Berichtsschluss mehr Gewinner- und weniger Verliereraktien. Zudem sind die üblichen Maße, die zur Identifizierung von Window Dressing verwendet werden, signifikant höher. Aktien, die in den letzten drei Tagen vor den Juli und Dezember Berichten einen starken Nachfrageüberschuss aufweisen, steigen in dieser Periode um durchschnittlich 20 Bsp. Dieser Anstieg ist nicht durch Informationstheorien erklärbar, da die Preise innerhalb von einer Woche auf ihr ursprüngliches Niveau zurückfallen. Aktien mit hoher Liquidität zeigen geringere Anstiege und kehren schneller zum Ausgangspreis zurück. Die Preisbewegungen lassen sich nicht durch einen einzelnen Faktor, wie Window Dressing oder Portfolio Pumping, erklären. / The first paper provides evidence that a liquidity shock to closed-end funds can transmit to open-end funds. Using the failure of the market for auction rate securities we show that forced asset sales of highly levered closed-end funds result in temporary price declines in those assets. Open-end funds that hold significant numbers of the affected stocks in turn experience outflows, forcing them to conduct additional fire-sales. These forced sales induce additional price pressure consistent with financial contagion. The second paper examines whether mutual bond funds increase their risk exposure through securities lending transactions by reinvesting the cash collateral of these transactions in risky assets. Consistent with such behavior, we find that the return volatility of government bond funds increases with the percentage of securities on loan. This relation is only evident among funds whose lending agent likely reinvests the lending collateral riskily and disappears if the lending program is managed by agents who typically cannot make risky reinvestments. The third paper provides a new way to measure the trading activity by mutual funds in the last three days of their reporting periods. Consistent with window dressing, heavy end-of-period (EoP) traders report more winner, fewer loser stocks and higher return and rank gaps, yet perform no better. Stocks with a high positive EoP trade imbalance show significant price increases of about 20 bps at the end of reporting periods in June and December. Inconsistent with information trading, prices revert within a week. Liquid stocks appreciate less strongly and revert more quickly. Finally, we show that window dressing, portfolio pumping, or fund flows alone are unlikely to explain our results.

La thèse analyse les effets de la régulation sur le risque systématique d’un panel de 17 grands opérateurs de télécommunications européens entre 1997 et 2012. La relation régulation/risque est étudiée sous trois angles : (i) via la modification de la distribution des revenus de la firme, (ii) la promotion de l’intensité concurrentielle, et (iii) les choix de structure financière des opérateurs. Une modélisation de l’impact de la régulation sur la structure financière de la firme met en évidence que la hausse stratégique de l’endettement peut accroitre ou décroitre le risque systématique. Trois méthodologies d’estimations du risque sont utilisées : les MCO et le filtre de Kalman sans et avec effet TGARCH. Les trois aspects de la relation risque/régulation sont ensuite abordés via une étude en données de panel (couvrant les ratios financiers, l’intensité concurrentielle, l’intensité et le régime de régulation) puis en évaluant la réaction du risque aux annonces d’évolutions du cadre réglementaire européen (étude d’évènements). / The thesis analyzes the effects of regulation on the systematic risk of a panel of 17 leading European telecommunications operators between 1997 and 2012. The regulation / risk relationship is studied through: (i) the changes in the firm income distribution, (ii) the promotion of competitive intensity, and (iii) the operators' choice of financial structure. Modeling the impact of regulation on the financial structure of the firm highlights that strategic increase in debt may increase or decrease the systematic risk. Three estimation methodologies of risk are used: OLS and Kalman filter technics with and without TGARCH effect. The three aspects of risk / regulation relationship are then addressed through a panel data study (covering financial ratios, competitive intensity, and regulatory regime index) and then by an events study evaluating market reactions to announcements of changes in the European regulatory framework.

Die studie vergelyk die prestasie van 'n koop-en-hou-strategie met die van 'n tydsberekeningstrategie binne die raamwerk van die arbitrasie-prysbepalingsteorie (APT) op die nywerheidsindeks van die Johannesburgse Aandelebeurs (JA). Die periode van die studie is oor twee tydperke, naamlik Januarie 1970 tot September 1987 en Januarie 1989 tot Junie 1997. Die langtermyntendens van die nywerheidsindeks en APT-faktore is bepaal deur die beste nie-reglynige model vir elke tydreeks te vind. Reglynige meervoudige stapsgewyse regressie-ontleding is gebruik om die bewegings van die nywerheidsindeks rondom die langtermyntendens te voorspel. Die sloeringsreekse van die langtermyntendensresidutelling van die APT-faktore en die sloeringsreekse van die eerste-ordeverskiltelling van die langtermyntendensresidutelling is as moontlike voorspellers gebruik. Gegrond hierop is beslissingslyne ontwik:kel wat gebruik is vir die implementering van 'n tydsberekeningstrategie. Die resultate van die studie is die volgende: • Waar die sloeringsreekse van die langtermyntendensresidutelling van die APTfaktore as moontlike voorspellers gebruik is, is die risiko-aangepaste opbrengskoers van 'n tydsberekeningstrategie 6, 41 persent en 0, 71 persent b6 die van 'n koop-en-hou-strategie vir tydperk een en twee onderskeidelik. • Waar die sloeringsreekse van die eerste-ordeverskiltelling van die langtermyntendensresidutelling van die APT-faktore as moontlike voorspellers gebruik is, is die risiko-aangepaste opbrengskoers van 'n tydsberekeningstrategie 10,40 persent en 1,04 persent b6 die van 'n koop-enhou- strategie vir tydperk een en twee onderskeidelik. Die belangrikste gevolgtrekking van die studie is dat die APT en 'n tydsberekeningstrategie teoreties en prakties versoenbaar is op die JA. Aanbevelings vir toekomstige navorsing is die volgende: ( 1) sistematiese risikofaktore, anders as makro-ekonomiese faktore, behoort identifiseer te word wat die voorspellingswaarde van die faktore in die tweede tydperk van die studie kan verhoog; (2) elke stap van die model wat ontwikkel is, behoort op elke indeks van die JA toegepas te word om die risiko-aangepaste opbrengskoers van 'n tydsberekeningstrategie toegepas op elkeen van die indekse met die van 'n koop-en-hou-strategie te vergelyk; en (3) die invloed van transaksiekoste en dividende op die potensiele voordele van tydsberekening moet bepaal word. / The study compares the performance of a buy-and-hold strategy with that of a markettiming strategy in the framework of the arbitrage pricing theory (APT) applied to the industrial index of the Johannesburg Stock Exchange (JSE). The study period is divided into two parts, namely January 1970 to September 1987 and January 1989 to June 1997. The long-term trend of the industrial index and every APT factor is determined by finding the best nonlinear model for each time series. Linear multiple stepwise regression analysis, with the lagged time series of the long-term trend error terms of the APT factors, is used to forecast the movement of the industrial index around its long-term trend. Decision lines were developed to implement a market-timing strategy. The results of the study are as follows: • Where the lagged time series of the long-term trend error terms of the APT factors were used as possible predictors, the risk-adjusted return of a markettiming strategy was 6, 41 percent and 0, 71 percent higher than that of a buyand- hold strategy for periods one and two respectively. • Where the lagged time series of the first-order difference of the long-term trend error term of the APT factors were used as possible predictors, the riskadjusted return of the market-timing strategy was 10,40 percent and 1,04 percent higher than that of a buy-and-hold strategy for periods one and two respectively. The main conclusion of the study is that the APT and a market-timing strategy are theoretically and practically reconcilable on the JSE. The main recommendations of the study are the following: (1) systematic risk factors, other than macroeconomic factors, should be identified in order to increase the forecasting value of these factors in the second period of the study; (2) each step of the model developed in this study should be repeated on every index of the JSE; and (3) the influence of transaction costs and dividends on the potential benefits of a market-timing strategy should be determined. / Business Management / DCom (Sakebestuur)

This study shows that managers of short-term insurers may improve their financial results if they can identify and manage the factors that are critical to their financial results. The development and application of the concept of critical success factors are therefore used as a basis for this study. The study reviews the functions performed by short-term insurers, focusing on the effect these functions have on their cash flows. Selection and pricing of risk are discussed in detail. The underwriting cycle in South Africa, and several possible causes of the cycle are investigated. Reinsurance, claims handling and rilanagement expenses are important components of the cash flows of short-term insurers and are therefore examined in detail. The optimum risk level at various combinations of underwriting and investment income is empirically tested, using the financial results of several insurers. The study investigates different approaches to the measurement of financial success of insurers, and the return on shareholders' funds is found to provide the fairest and most reliable method. Empirical comparisons are made on the financial results of the insurers that participated in the study to distinguish between those that are financially successful and those that are not. To discover what the industry consider to be their critical financial success factors, a postal survey was done of key decision makers in the South African short-term insurance industry. Respondents identified several success factors, but did not include some success factors discovered during the review of the literature. Respondents apparently experienced difficulty in separating strategic issues from operational ones. The survey revealed that the pricing of risk is problematic for short-term insurers. The importance of the investment function is also underestimated by the industry. The study concludes that the combined systematic risk of the investment and underwriting portfolios is a critical success factor, along with the capital base of the insurer, the ability of the insurer to use the leverage provided by using policyholders' funds as free reserves and the size and direction of an insurer's cash flows. / Business Management / D. Com (Business Management)

Cette thèse examine la responsabilité sociale des entreprises (RSE) par les entreprises de secteurs controverses. Dans le premier chapitre, on évalue les stratégies en RSE pour 565 entreprises de secteurs controverses de 1991 à 2013 en estimant la relation compensatoire entre Irresponsabilité Sociale des Entreprises (ISE) et RSE. On montre que ces entreprises tendent à compenser pour leur ISE en s'engageant dans des domaines stratégiques de RSE tels que la protection de l'environnement et le respect des communautés locales avec un manque d'engagement dans d'autres activités telles la gouvernance d'entreprise. Dans le deuxième chapitre, on examine si l'engagement RSE de 499 entreprises de secteurs controverses est susceptible de diminuer leur risque financier. Nos résultats montrent qu'un engagement RSE stratégique réduit le risque idiosyncratique et total pour certaines industries controversées et que le manque d'engagement dans les activités de gouvernance augmente leur risque. Le troisième chapitre examine la divulgation sociétale en tant que mécanisme de reddition de comptes dans le contexte d'un incident environnemental majeur. L'étude de cas des stratégies RSE utilisées par l'entreprise Canadienne En bridge, durant sa réponse a l'incident de déversement de parole en 2010 révèle que ses rapports RSE sont souvent optimistes et ne réussissent pas a décrire son incapacité à faire face aux problèmes de sécurité ayant entrainé l'incident; et ont aussi sous-estime le volume du déversement et la difficulté du nettoyage, ainsi mettant en question l'effet des activités RSE compare à l'effet de facteurs contextuels dans la protection de l'entreprise durant la crise. / This thesis is composed of three chapters that examine corporate social responsibility (CSR) within firms in controversial sectors. In the first chapter, we evaluate patterns of investment in CSR for 565 US publicly traded companies in eight controversial sectors between 1991 and 2013 by assessing the relationship between CSR and Corporate Social Irresponsibility (CSI). We show that firms in controversial sectors compensate for their CSI by engaging in strategic CSR areas such as environmental protection and community development with a lack of engagement towards other areas, such as corporate governance. In the second chapter, we determine whether engagement in specific CSR activities for 499 US companies in controversial sectors decreases their financial risk. We show that engaging in specific CSR activities considered as strategic reduces idiosyncratic and total risk for some controversial industries; and that poor engagement in corporate governance activities increases firm risk. In the third chapter, we investigate CSR reporting as an important mechanism for stakeholder accountability in the context of an environmental crisis. We perform a case study analysis of the CSR strategies used by the Canadian oil company Enbridge in its response to the July 2010 Kalamazoo spill and revealed that Enbridge's CSR reports were frequently optimistic and failed to describe the company's inability to deal with known safety problems that led to spill; and underestimated both the volume of the spill and the difficulty of the cleanup, thus making it difficult to distinguish the effects of the CSR efforts from the effects of other contextual and external factors.

Abstracts in English, Afrikaans and Sesotho / As one of the renowned anomalies in modern investment theory, the low idiosyncratic volatility anomaly may be the most bewildering and captivating of them all. The anomaly defies the traditional asset pricing theories of modern portfolio theory, which state the fundamental principle that high-risk portfolios are compensated for with higher expected returns. This study determined if the low idiosyncratic volatility premium is present on the cross-section of share returns of the JSE. 12-, 36- and 60-month volatility estimation periods were used in this study to determine if this has any significant effect on share returns. A relevant 26-year sample period from January 1994 to December 2019 was employed. In examining the CAPM OLS regression results utilising the 60-month idiosyncratic volatility estimation period, statistically significant evidence was found to support the alternative hypothesis of a low idiosyncratic volatility anomaly on the cross-sectional returns on the JSE. These findings are supported by a statistically significant alpha for five of the six portfolios examined and clearly indicate the superior performance of the low volatility portfolio in contrast to the high idiosyncratic volatility portfolios. These findings of the 60-month CAPM regression analysis provide clear evidence of a low idiosyncratic volatility anomaly and reject the null hypothesis that there is no statistically significant evidence in favour of a low idiosyncratic volatility anomaly on the cross-section of share returns on the JSE after estimating volatility utilising a 60-month volatility estimation period. / As een van die bekendste anomalieë in moderne beleggingsteorie, is die lae idiosinkratiese gestadigheidsanomalie moontlik die mees verbysterende en boeiende anomalie van almal. Hierdie besondere anomalie bied ʼn uitdaging aan die tradisionele bateprysingsteorie van moderne portefeuljeteorie, die grondbeginsel waarvolgens daar vir hoërisiko-portefeuljes vergoed word deur hoër verwagte opbrengste. Die doel van hierdie studie is om te bepaal of die lae idiosinkratiese gestadigheidspremie aanwesig is by die deursnee-aandeleopbrengste op die JSE. In hierdie studie, is gestadigheidsramingstydperke van 12, 36 en 60 maande gebruik om te bepaal of dit enige beduidende uitwerking op aandeleopbrengste het. ʼn Relevante steekproeftydperk van 26 jaar van Januarie 1994 tot Desember 2019 is gebruik. Deur ondersoek van regressieresultate van die kapitaalbateprysingsmodel (KBPM) kleinste-kwadratemetode aan die hand van ʼn idiosinkratiese gestadigheidsramingstydperk van 60 maande is statisties-beduidende bewyse gevind om die alternatiewe hipotese van ʼn lae idiosinkratiese gestadigheidsanomalie in die deursnee-opbrengste op die JSE te ondersteun. Hierdie bevindings word ondersteun deur ʼn statisties-beduidende alfa vir vyf van die ses portefeuljes wat ondersoek is en dit dui duidelik op die superieure prestasie van die laegestadigheidsportefeulje in kontras met die hoë idiosinkratiese gestadigheidsportefeuljes. Die bevindings van die KBPM-regressie-analise van 60 maande voorsien duidelike bewyse van ʼn lae idiosinkratiese gestadigheidsanomalie en verwerp die nulhipotese dat daar nie statisties-beduidende bewyse is ten gunste van ʼn lae idiosinkratiese gestadigheidsanomalie in die deursnee-aandeleopbrengste op die JSE nie nadat gestadigheid geraam is aan die hand van ʼn gestadigheidsramingstydperk van 60 maande. / E le e nngwe ya diphoso tse tummeng kgopolong ya sejwale-jwale ya matsete, bothata bo tlase ba ho hloka botsitso e ka ba ntho e makatsang le e hohelang ka ho fetisisa. Phoso e ikgethileng ha e latele dikgopolo tsa ditheko tsa thekiso ya thepa ya sejwale-jwale, e hlalosang molao-theo wa hore dipotefoliyo tse kotsing e kgolo di lefellwa bakeng sa dikgutliso tse phahameng tse lebelletsweng. Phuputso ena e ne e ikemiseditse ho fumana hore na tefo e tlase ya botsitso e teng dikarolong tse sa tshwaneng tsa dikgutliso tsa dikabelo ho JSE. Phuputsong ena ho sebedisitswe dinako tsa tekanyetso ya ho hloka botsitso ya dikgwedi tse 12, 36 le tse 60 ho fumana hore na sena se na le phello e kgolo ho dikgutliso tsa dikabelo. Nako ya sampole e loketseng ya dilemo tse 26 ho tloha ka Pherekgong 1994 ho isa ho Tshitwe 2019 e ile ya sebediswa. Ha ho hlahlojwa sephetho sa tekanyo ya CAPM OLS ho sebediswa nako ya dikgakanyo tsa ho hloka botsitso ha dikgwedi tse 60, ho fumanwe bopaki ba bohlokwa ho tshehetsa mohopolo o mong wa phokotso dikgutlisong tsa dikarolo tse fapaneng ho JSE. Diphumano tsena di tsheheditswe ke qaleho ya dipalo bakeng sa dipotefoliyo tse hlano ho tse tsheletseng tse hlahlobilweng mme di bontsha tshebetso e phahameng ya potefolio e tlase ya ho hloka botsitso ho fapana le dipotefoliyo tse phahameng tsa ho hloka botsitso. Diphumano tsena tsa tlhahlobo ya tekanyo ya CAPM ya dikgwedi tse 60 di fana ka bopaki bo hlakileng ba phokotso e sa tlwaelehang ya ho hloka botsitso le ho hanyetsa kgopolo-taba ya hore ha ho na bopaki ba dipalo-palo bo tshehetsang boemo bo tlase ba ho hloka botsitso bo sa tlwaelehang dikarolong tse sa tshwaneng tsa dikabelo ho JSE kamora ho lekanyetsa ho hloka botsitso ho sebedisang nako ya dikgakanyo tsa ho hloka botsitso ya dikgwedi tse 60. / Business Management / M. Com. (Business Management)

Cette thèse est organisée en trois chapitres. Dans le premier chapitre, qui est co-écrit avec Ilze Kalnina, nous proposons un test statistique pour évaluer l’adéquation de la volatilité idiosyncratique comme mesure du risque idioyncratique. Nous proposons un test statistique qui est basé sur l’idée qu’un bon proxy du risque idiosyncratique devrait être non correélé à travers les actifs financiers. Nous démontrons que l’estimation de la volatililité est sujet à des erreurs qui rendent le test non standard. Nous proposons un modèle à facteurs qui permet de réduire sinon éliminer les corrélations dans la volatilité idiosyncratique, avec comme ultime but d’ aboutir à un facteur qui satisfait mieux aux critères souhaités du risque idiosyncratique. Dans le deuxième chapitre de ma thèse, qui est co-écrit avec Christian Dorion et Pierre Chaigneau, nous proposons une méthodologie pour étudier l’importance des risques d’ordres supérieurs dans la valorisation des actifs financiers. A la suite de Kraus and Litzenberger (1976) et Harvey and Siddique (2000a), beaucoup d’études ont analysé l’aversion aux risques de skewness et kurtosis de façon inconditionnelle. Dans ce chapitre, nous proposons une méthodogie qui permet de faire une analyse conditionnelle assez précise de l’aversion au risques d’ordres superieurs. Notre étude complémente la littérature dans la mesure ou nous étudions aussi la valuation des risques d’ordre plus élevé que la kurtosis à savoir l’hyperskewness et l’hyperkurtosis qui sont théoriquement valorisés dans certaines fonction d’utilité comme le CRRA. Dans le dernier chapitre de ma thése, j’étudie la structure à terme de la prime de risque pour le risque de co-skewness, un risque qui mesure l’asymmétrie systématique dans les actions individuelles. Nous y proposons une méthode assez générale qui permet de faire une analyze mutli-horizon contrairement à la plupart des études existantes. / This thesis is organized in three chapters. In the first chapter (which is co-authored with Ilze Kalnina), we propose a statistical test to assess the adequacy of the most popular measure of idiosyncratic risk, which is the idiosyncratic volatility. Our test statistic exploits the idea that a “good" measure of the idiosyncratic risk should be uncorrelated in the cross-section. Using in-fill asymptotics, we study the theoretical properties of the test and find that it has a non-standard behaviour due to various biases induced by the latency of the idiosyncratic volatility. Moreover, we propose a regression model that can be used to reduce if not eliminate the cross-sectional dependences in assets idiosyncratic volatilities. The second chapter of my thesis is the fruit of a colaboration with Christian Dorion and Pierre Chaigneau. In this chapter, we study the relevance of higher-order risk aversion in asset pricing. The evidence in Kraus and Litzenberger (1976) and Harvey and Siddique (2000a) has spurred the literature on the estimation of the risk premiums attached to skewness and kurtosis risk in addition to the standard variance risk. However, most of these studies focus on the estimation of unconditional premiums or average premiums. In this chapter, we propose a methodology that allows to accurately estimate the time-varying higher-order risk aversions using options prices. Our study complements the literature as we also study the higher-order risks beyond the kurtosis such as hyperskewness and hyperkurtosis risks which are valued by a CRRA investor. . In my third chapter, I study the term-structure of price of co-skewness risk. Co-Skewness risk captures the portion of the stock returns asymmetry that arises as a result of market returns asymmetry. I propose a general methodology that allows to study the multi-horizon pricing of this risk in contrast to many existing studies.

台灣早期有關系統風險（β）的研究皆指出β不能解釋台灣股票報酬的變異，故控尋更能解釋股票報酬的風險因素為本文的主要目的之一。 本研究分析民國71年7月至85年5月股票上市公司資料（排除金融、保險、及變更交易方式的公司）。因民國79年股價指數從2月的最高點12,495急遽下滑至10月的2,560，故分析上將79年度予以排除。在71年7月至78年12月的時段中，整體市場因素（RM-RF）不能解釋股票報酬的變異。此點發現與台灣早期研究的結論一致。其他變數顯著者僅有與規模有關的因素（SZSMB），或與負債比率有關的因素（DEHML），其中以 SZSMB的解釋能力最強。在民國80年1月至85年5月的時段中，所有模式中整體市場因素（ RM-RF）的係數皆顯著，並且是所有因素中最顯著者。這點發現與前時段（71年7月至78年12月）的結果有很大的不同。其他的變數顯著者，有代表成長機會的BMHML（與淨值市價比有關的因素）、EPHML（與益本比有關的因素）、或CPHML（與營運現金市價比有關的因素），及代表利率結構有關的風險因素TERM（與利率期間結構有關的風險溢酬）、或DFT（與利率違約風險有關的風險溢酬）。其中以（RM-RF）、EPHML、CPHML及TERM的風險組合最能解釋股票報酬的變異。 應用更完整的股票報酬解釋變數，探討股票報酬與盈餘間的關係，亦為本文主要目的之一。經分析以(1)各時段最能解釋股票報酬的因素組合為基礎，計算異常報酬；(2)單獨的以整體市場因素（RM-RF）為基礎計算異常報酬，然後再分別估出盈餘反應比較係數（ERC）比較之。結果顯示，以各時段最能顯著解釋股票報酬的因素組合為基礎的ERC為正的顯著，且其ERC大於只以整體市場因素（RM-RF）為基礎所算出的ERC。 另外，關於盈餘品質假說之測試，經以公司規模大小為虛擬變數放入迴歸式中，結果顯示，代表大公司的虛擬變數之係數時而為正，時而為負，且都不顯著，故盈餘品質假說未獲得支持。 再者，關於成長機會與ERC關係之測試，經以公司成長機會大小為虛擬變數放迴歸式中，結果顯示，代表成長機會的虛擬變數之系數時而為正，時而為負，且大都不顯著，故成長機會大的公司之ERC大於成長機會小的公司之ERC的假說，未獲得實證的支持。 / Earlier studies (Chen 1990; Chiu 1990; and Wang 1992) found that systematic risk (β) could not explain the variance of stock returns in Taiwan. The findings were inconsistent with the Capital Asset Pricing Model (CAPM). One of the major purposes of this paper is to examine the factors that have higher explanatory power of stock returns. To test the hypotheses, this study uses the data of Taiwanese listed companies covering the period from July 1982 to may 1996. The 1990 data are excluded because the stock market index climbed to a record high of 12,495 in February 1990 and then fell sharply to allow level of 2,560 in October 1990. The "crash" might cause structural changes in stock market, so the analyses are conducted separately for the periods before and after the crash, namely the prior-crash period (from July 1982 to December 1989) and the post-crash period (from January 1991 to May 1996). The empirical results show that for the prior-crash period the overall market factor (market returns minus risk free rate, RM-RF) can not explain the variance of stock returns. The findings are consistent with those of previous studies. However, we find that the factor-related to size (SZSMB) and the factor related to debt/equity ratio (DEHML) have significant association with stock returns. Furthermore, SZSMB has higher explanatory power. In contrast, the overall market factor is the most significant factor for the post-crash period. Other factors that are significant consisted of (1) proxies for growth opportunities, including book-to-market equity (BMHML), earnings/price ratio (EPHML), and cash flow/price ratio (CPHML), and (2) the factors related to interest structure, including term structure (TERM) and default risk (DFT). Among these factors, the set of RM-RF, EPHML, CPHML, and TERM explains the variance of stock returns most. Another purpose of this paper is to use the aforementioned findings to study the relationship between stock returns and earnings. The results show that the earnings response coefficients based on the most explanatory factor portfolio of each period are positive and significant, and are greater than those based on the traditional systematic risk (β). The tests for earnings quality hypothesis indicate that the coefficients of the dummy variable proxies for big companies are insignificant. The earnings quality hypothesis is not supported. The tests regarding the relationship between growth opportunities and earnings response coefficients show that the coefficients of the dummy variable proxies for high growth companies are unstable. The hypothesis that the earnings response coefficients of high growth companies are greater than those of low growth companies is not supported by empirical evidence.

Notre thèse consiste à expliquer, en apportant quelques éléments théoriques, les imperfections des stress tests macro-prudentiels d’EBA/BCE, et de proposer une nouvelle méthodologie de leur application ainsi que deux stress tests spécifiques en complément. Nous montrons que les stress tests macro-prudentiels peuvent être non pertinents lorsque les deux hypothèses fondamentales du modèle de base de Gordy-Vasicek utilisé pour évaluer le capital réglementaire des banques en méthodes internes (IRB) dans le cadre du risque de crédit (portefeuille de crédit asymptotiquement granulaire et présence d’une seule source de risque systématique qui est la conjoncture macro-économique), ne sont pas respectées. Premièrement, ils existent des portefeuilles concentrés pour lesquels les macro-stress tests ne sont pas suffisants pour mesurer les pertes potentielles, voire inefficaces si ces portefeuilles impliquent des contreparties non cycliques. Deuxièmement, le risque systématique peut provenir de plusieurs sources ; le modèle actuel à un facteur empêche la répercussion propre des chocs « macro ».Nous proposons un stress test spécifique de crédit qui permet d’appréhender le risque spécifique de crédit d’un portefeuille concentré, et un stress test spécifique de liquidité qui permet de mesurer l’impact des chocs spécifiques de liquidité sur la solvabilité de la banque. Nous proposons aussi une généralisation multifactorielle de la fonction d’évaluation du capital réglementaire en IRB, qui permet d’appliquer les chocs des macro-stress tests sur chaque portefeuille sectoriel, en stressant de façon claire, précise et transparente les facteurs de risque systématique l’impactant. Cette méthodologie permet une répercussion propre de ces chocs sur la probabilité de défaut conditionnelle des contreparties de ces portefeuilles et donc une meilleure évaluation de la charge en capital de la banque. / Our thesis consists in explaining, by bringing some theoretical elements, the imperfections of EBA / BCE macro-prudential stress tests, and proposing a new methodology of their application as well as two specific stress tests in addition. We show that macro-prudential stress tests may be irrelevant when the two basic assumptions of the Gordy-Vasicek core model used to assess banks regulatory capital in internal methods (IRB) in the context of credit risk (asymptotically granular credit portfolio and presence of a single source of systematic risk which is the macroeconomic conjuncture), are not respected. Firstly, they exist concentrated portfolios for which macro-stress tests are not sufficient to measure potential losses or even ineffective in the case where these portfolios involve non-cyclical counterparties. Secondly, systematic risk can come from several sources; the actual one-factor model doesn’t allow a proper repercussion of the “macro” shocks. We propose a specific credit stress test which makes possible to apprehend the specific credit risk of a concentrated portfolio, as well as a specific liquidity stress test which makes possible to measure the impact of liquidity shocks on the bank’s solvency. We also propose a multifactorial generalization of the regulatory capital valuation model in IRB, which allows applying macro-stress tests shocks on each sectorial portfolio, stressing in a clear, precise and transparent way the systematic risk factors impacting it. This methodology allows a proper impact of these shocks on the conditional probability of default of the counterparties of these portfolios and therefore a better evaluation of the capital charge of the bank.