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.

Summaries in English, Afrikaans and Zulu / Orientation: Security personnel work in a high risk and consequently high stress environment. This may negatively affect their wellbeing. Owing to the high crime rate in South Africa, one of the continuous stressors security personnel experience might be fearing for their lives. If security personnel fail to use effective coping strategies they will remain stressed, and this may have a negative impact on them, and their organisation or community. Challenges such as work stress in the South African security industry have not been comprehensively researched or documented (Sibanyoni, 2014). Consequently, no South African questionnaire measuring coping with stress or a stress management model for dealing with stress in a security environment, could be found. Research purpose: The general aim of the research was to develop a valid and reliable coping questionnaire and stress management model for high stress security occupations. Research methodology: A questionnaire development process, as suggested by scientific literature, was followed. The process entailed (1) determining coping strategies by means of a literature review, (2) developing the coping questionnaire, (3) administering the questionnaire to the target population, and (4) statistical analysis. The stress management model was developed by combining the results of the confirmatory factor analysis (CFA) and canonical correlation analysis (CCA). The development of the questionnaire was based on a sample of 381 active duty security personnel working in a high stress security environment in South Africa. Main findings: The study resulted in the development of a psychometrically sound 39-item questionnaire. The following 12 empirically validated healthy and unhealthy coping strategies were identified: (1) social support, (2) group cohesion, (3) physical exercise, (4) relaxation, (5) social media addiction, (6) healthy sleeping habits, (7) healthy diet, (8) training, (9) humour, (10) religion, (11) avoidance, and (12) denial. CFA confirmed both the construct and content validity, and composite reliability. The questionnaire was found to be invariant, and could thus be applied to different groups in high stress security occupations. A stress management model indicating the interrelationship between personality and coping was also developed. Contribution/value-add: The main contribution of this study was the development of a valid coping questionnaire and stress management model. By identifying the specific coping strategies, targeted stress management interventions could be developed. This could contribute to the overall wellness of security personnel working in high stress occupations, resulting in a healthy organisation and sound relationships with the community. Security organisations could also use the model during assessments to identify candidates with personality traits that would lead to healthier coping strategies, thereby selecting personnel that could better adapt to a security environment. / Oriëntasie: Sekuriteitspersoneel werk in ’n hoë risiko en gevolglik ’n stresvolle omgewing. Dit kan hulle welstand negatief beïnvloed. As gevolg van die hoë misdaadsyfer in Suid-Afrika kan een van die deurlopende stressors wat sekuriteitspersoneel ervaar ’n vrees vir hulle lewens wees. Indien sekuriteitspersoneel nie effektiewe streshantering strategieë gebruik nie, kan hulle voortdurend stres ervaar en dit kan ’n negatiewe impak op hulleself, hulle organisasie of gemeenskap hê. Uitdagings soos beroepstres in die Suid-Afrikaanse sekuriteitsindustrie is nog nie deeglik nagevors of gedokumenteer nie (Sibanyoni, 2014). Gevolglik kon daar vir die sekuriteitsomgewing geen Suid-Afrikaanse vraelys wat streshantering meet of ’n stresbestuursmodel gevind word nie. Doel van die navorsing: Die algemene doel van die navorsing was om vir stresvolle sekuriteitsberoepe ’n geldige en betroubare streshanteringsvraelys en stresbestuursmodel te ontwikkel. Navorsingsmetodologie: ’n Vraelys ontwikkelingsproses, soos deur wetenskaplike literatuur voorgestel, is gevolg. Die proses het die volgende behels: (1) die vasstel van die streshantering strategieë deur middel van ’n literatuuroorsig, (2) die ontwikkeling van die streshanteringsvraelys, (3) administrasie van die vraelys aan die teiken populasie en (4) statistiese analise. Die stresbestuursmodel is ontwikkel deur die resultate van die bevestigende faktoranalise (BFA) en die kanoniese korrelasie analise te kombineer. Die ontwikkeling van die vraelys is gebaseer op ’n steekproef van 381 aktiewe diens sekuriteitspersoneel wat in Suid-Afrika in ’n stresvolle sekuriteitsomgewing werk. Hoofbevindinge: Die studie het tot ’n psigometries betroubare 39-item vraelys gelei. Twaalf empiries gestaafde gesonde en ongesonde streshantering strategieë is geïdentifiseer naamlik: (1) sosiale ondersteuning, (2) groep kohesie, (3) fisiese oefening, (4) ontspanning, (5) sosiale media verslawing, (6) gesonde slaapgewoontes, (7) gesonde dieet, (8) opleiding, (9) humor, (10) godsdiens, (11) vermyding en (12) ontkenning. BFA het die konstruk- en inhoudsgeldigheid so wel as die saamgestelde betroubaarheid bevestig. Die vraelys is invariant en kan dus op verskillende groepe in hoë stres sekuriteitsberoepe toegepas word. ’n Stresbestuursmodel wat die verwantskap tussen persoonlikheid en streshantering aandui is ook ontwikkel. Bydrae/waardetoevoeging: Die belangrikste bydrae van hierdie studie was die ontwikkeling van ’n geldige streshanteringsvraelys en stresbestuursmodel. Deur die spesifieke streshantering strategieë te identifiseer kan gefokusde streshantering intervensies ontwikkel word. Dit kan tot die algehele welstand van sekuriteitspersoneel wat in stresvolle beroepe werk bydra en derhalwe ’n gesonde organisasie en goeie verhoudings met die gemeenskap. Sekuriteitsorganisasies kan ook tydens keurings die model gebruik om kandidate met persoonlikheidstrekke, wat tot gesonder streshantering strategieë sal lei, te identifiseer en dus personeel kies wat beter by ’n sekuriteitsomgewing sal aanpas. / Isimo somqondo: Abasebenzi bezokuphepha basebenza ezindaweni ezinobungozi obuphakeme nengcindezi ephakeme. Lokhu kungaba nomthelela omubi esimeni sabo sempilo. Ngenxa yezinga lobugebengu eliphezulu eNingizimu Afrika, okukodwa okudala ingcindezi ngokuqhubekayo kubasebenzi bezokuphepha ukwesabela izimpilo zabo. Uma abasebenzi bezokuphepha bengasebenzisi amasu aphumelelayo okubhekana nalezi zimo, bazohlala benengcindezi futhi lokhu kungaba nomphumela omubi kubona, enhlanganweni yabo noma emphakathini wabo. Ucwaningo ngezinselelo ezinjengokucindezeleka emsebenzini ezimbonini zokuphepha lapha eNingizimu Afrika alwenziwanga futhi akubhaliwe kabanzi ngakho (Sibanyoni, 2014). Kanjalo, alutholakalanga uhlu lwemibuzo lwaseNingizimu Afrika olungalinganisa ukuthi abasebenzi bezokuphepha babhekana kanjani nengcindezi kanye nomlinganiso olawula ingcindezi ukubhekana nengcindezi ezindaweni zezokuphepha. Inhloso yocwaningo: Inhloso enkulu yocwaningo kwakuwukuqamba uhlu lwemibuzo oluqinisekile noluthembekile ukubhekana nengcindezi nomlinganiso wokulawula ingcindezi emisebenzini yezokuphepha enengcindezi ephakeme. Indlela yokwenza ucwaningo: Isenzo sokuqamba uhlu lwemibuzo njengoba kuhlongozwa yimibhalo yezesayensi silandelwe kulolu cwaningo. Lesi senzo sibe (1) nokuthola amasu okubhekana nengcindezi ngokubhekisa emibhalweni ehloliwe, (2) nokuqamba uhlu lwemibuzo ephathelene nokubhekana nengcindezi, (3) nokunikeza uhlu lwemibuzo kubantu abathintekayo, kanye (4) nokwenza uhlaziyo lwezibalo. Umlinganiso wokulawula ingcindezi wenziwe ngokuhlanganisa imiphumela yeConfirmatory Factor Analysis (CFA) neyeCanonical Correlation Analysis (CCA). Ukuqanjwa kohlu lwemibuzo kweyeme esampuleni labasebenzi bezokuphepha abangama-381 abamatasa emsebenzini abasebenza ezindaweni ezinengcindezi ephakeme eNingizimu Afrika. Okukhulu okutholakele ocwaningweni: Ucwaningo lube nomphumela ekuqanjweni kohlu lwemibuzo oluqinisekile ngokwesayikhomethri olunemibuzo angama-39. Kukhonjwe amasu okubhekana nengcindezi ayishumi nambili aqinisekiswe ngokubukisiswa asesimeni esiphilile nesingaphilile sempilo, okubalwa kuwo, (1) uxhaso lomphakathi, (2) ukuba ndawonye kweqembu, (3) ukuzivocavoca umzimba, (4) ukuziphumuza, (5) ukuba yisigqili semithombo yomphakathi, (6) imikhuba emihle yokulala, (7) uqeqesho, (8) amahlaya, (10) inkolo, (11) ukuxwaya, kanye (12) nokwala. ICFA iqinisekise ukuba neqiniso kombono nokuqukethwe, kanye nokwethembeka okuxubile. Kutholakele ukuthi uhlu lwemibuzo aluguquki futhi lungasetshenziswa emaqenjini ehlukene emisebenzini yezokuphepha anengcindezi ephakeme. Kuthuthukiswe nomlinganiso olawula ingcindezi okhombisa ubudlelwano phakathi komuntu isibili nokubhekana nengcindezi. Umnikelo: Umnikelo omkhulu walolu cwaningo kube ukuqamba uhlu lwemibuzo oluqinisekile ukubhekana nengcindezi kanye nomlinganiso wokulawula ingcindezi. Ngokukhomba amasu aqondene nokubhekana nengcindezi, kungathuthukiswa izindlela ezihlosiwe zokulawula ingcindezi. Lokhu kunganikela esimeni esihle sempilo yabasebenzi bezokuphepha abasebenza imisebenzi enengcindezi ephakeme, okuzoholela enhlanganweni esesimeni esihle nasebudlelwaneni obuhle nomphakathi. Izinhlangano zezokuphepha nazo zingawusebenzisa lomlinganiso ngesikhathi sokuhlola ukubona abafundi abanezici ezinomthelela omuhle, kumasu abhekana nengcindezi asesimeni esihle, ezizobenza bakhethe abasebenzi abazongena kahle ezindaweni zokuphepha. / Industrial and Organisational Psychology / D. Phil. (Industrial and Organisational Psychology)