Modelling of size-based portfolios using a mixture of normal distributions
- Authors: Janse Van Rensburg, Stéfan
- Date: 2009
- Subjects: Capital assets pricing model
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:10569 , http://hdl.handle.net/10948/985 , Capital assets pricing model
- Description: From option pricing using the Black and Scholes model, to determining the signi cance of regression coe cients in a capital asset pricing model (CAPM), the assumption of normality was pervasive throughout the eld of nance. This was despite evidence that nancial returns were non-normal, skewed and heavy- tailed. In addition to non-normality, there remained questions about the e ect of rm size on returns. Studies examining these di erences were limited to ex- amining the mean return, with respect to an asset pricing model, and did not consider higher moments. Janse van Rensburg, Sharp and Friskin (in press) attempted to address both the problem of non-normality and size simultaneously. They (Janse van Rens- burg et al in press) tted a mixture of two normal distributions, with common mean but di erent variances, to a small capitalisation portfolio and a large cap- italisation portfolio. Comparison of the mixture distributions yielded valuable insight into the di erences between the small and large capitalisation portfolios' risk. Janse van Rensburg et al (in press), however, identi ed several shortcom- ings within their work. These included data problems, such as survivorship bias and the exclusion of dividends, and the questionable use of standard statistical tests in the presence of non-normality. This study sought to correct the problems noted in the paper by Janse van Rensburg et al (in press) and to expand upon their research. To this end survivorship bias was eliminated and an e ective dividend was included into the return calculations. Weekly data were used, rather than the monthly data of Janse van Rensburg et al (in press). More portfolios, over shorter holding periods, were considered. This allowed the authors to test whether Janse van Rensburg et al's (in press) ndings remained valid under conditions di erent to their original study. Inference was also based on bootstrapped statistics, in order to circumvent problems associated with non-normality. Additionally, several di erent speci cations of the normal mixture distribution were considered, as opposed to only the two-component scale mixture. In the following, Chapter 2 provided a literature review of previous studies on return distributions and size e ects. The data, data preparation and portfolio formation were discussed in Chapter 3. Chapter 4 gave an overview of the statistical methods and tests used throughout the study. The empirical results of these tests, prior to risk adjustment, were presented in Chapter 5. The impact of risk adjustment on the distribution of returns was documented in Chapter 6. The study ended, Chapter 7, with a summary of the results and suggestions for future research.
- Full Text:
- Date Issued: 2009
- Authors: Janse Van Rensburg, Stéfan
- Date: 2009
- Subjects: Capital assets pricing model
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:10569 , http://hdl.handle.net/10948/985 , Capital assets pricing model
- Description: From option pricing using the Black and Scholes model, to determining the signi cance of regression coe cients in a capital asset pricing model (CAPM), the assumption of normality was pervasive throughout the eld of nance. This was despite evidence that nancial returns were non-normal, skewed and heavy- tailed. In addition to non-normality, there remained questions about the e ect of rm size on returns. Studies examining these di erences were limited to ex- amining the mean return, with respect to an asset pricing model, and did not consider higher moments. Janse van Rensburg, Sharp and Friskin (in press) attempted to address both the problem of non-normality and size simultaneously. They (Janse van Rens- burg et al in press) tted a mixture of two normal distributions, with common mean but di erent variances, to a small capitalisation portfolio and a large cap- italisation portfolio. Comparison of the mixture distributions yielded valuable insight into the di erences between the small and large capitalisation portfolios' risk. Janse van Rensburg et al (in press), however, identi ed several shortcom- ings within their work. These included data problems, such as survivorship bias and the exclusion of dividends, and the questionable use of standard statistical tests in the presence of non-normality. This study sought to correct the problems noted in the paper by Janse van Rensburg et al (in press) and to expand upon their research. To this end survivorship bias was eliminated and an e ective dividend was included into the return calculations. Weekly data were used, rather than the monthly data of Janse van Rensburg et al (in press). More portfolios, over shorter holding periods, were considered. This allowed the authors to test whether Janse van Rensburg et al's (in press) ndings remained valid under conditions di erent to their original study. Inference was also based on bootstrapped statistics, in order to circumvent problems associated with non-normality. Additionally, several di erent speci cations of the normal mixture distribution were considered, as opposed to only the two-component scale mixture. In the following, Chapter 2 provided a literature review of previous studies on return distributions and size e ects. The data, data preparation and portfolio formation were discussed in Chapter 3. Chapter 4 gave an overview of the statistical methods and tests used throughout the study. The empirical results of these tests, prior to risk adjustment, were presented in Chapter 5. The impact of risk adjustment on the distribution of returns was documented in Chapter 6. The study ended, Chapter 7, with a summary of the results and suggestions for future research.
- Full Text:
- Date Issued: 2009
The current role of modern portfolio theory in asset management practice in South Africa
- Authors: Garaba, Masimba
- Date: 2005
- Subjects: Portfolio management -- South Africa , Investments -- South Africa , Bank investments -- Mathematical models , Capital assets pricing model , Asset -- Liability management , Money market -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:965 , http://hdl.handle.net/10962/d1002699 , Portfolio management -- South Africa , Investments -- South Africa , Bank investments -- Mathematical models , Capital assets pricing model , Asset -- Liability management , Money market -- South Africa
- Description: This research examines the role that modern portfolio theory (MPT) plays in current South Africa asset management practice in comparison to other portfolio management techniques and security evaluation methods. The purpose of asset management is to pool complementary financial market expertise, in order to generate returns in excess of the market return on the investments of the owners of financial resources that are entrusted to the firm, since the owners of financial resources might not be able to make superior investment decisions on their own. The research presents and discusses the literature pertaining to modern portfolio theory, traditional portfolio theory (fundamental and technical analyses), and behavioural finance theory. The implication of the efficient market hypothesis in relation to all the portfolio management theories is also presented and discussed. In line with a positivist paradigm, the survey research methodology, which combines both qualitative and quantitative aspects, was adopted. The instrument used for data collection was a questionnaire, which was found to be reliable and valid for this research. The questionnaire encompassed the Lickert scale to measure the data. The results of the analysis were interpreted using descriptive statistics. The results of this research suggest that modern portfolio theory does not play a significant role in the management of portfolios and security evaluation in South Africa. South African asset managers regard fundamental analysis as the most significant method of security evaluation in the management of portfolios. Technical analysis and econometric models are regarded as playing a moderate role and complement fundamental analysis whilst behavioural finance models play the least role. This research recommends an integrated portfolio management strategy that incorporates MPT, traditional portfolio theory and behavioural finance models to enhance investor value and protection.
- Full Text:
- Date Issued: 2005
- Authors: Garaba, Masimba
- Date: 2005
- Subjects: Portfolio management -- South Africa , Investments -- South Africa , Bank investments -- Mathematical models , Capital assets pricing model , Asset -- Liability management , Money market -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:965 , http://hdl.handle.net/10962/d1002699 , Portfolio management -- South Africa , Investments -- South Africa , Bank investments -- Mathematical models , Capital assets pricing model , Asset -- Liability management , Money market -- South Africa
- Description: This research examines the role that modern portfolio theory (MPT) plays in current South Africa asset management practice in comparison to other portfolio management techniques and security evaluation methods. The purpose of asset management is to pool complementary financial market expertise, in order to generate returns in excess of the market return on the investments of the owners of financial resources that are entrusted to the firm, since the owners of financial resources might not be able to make superior investment decisions on their own. The research presents and discusses the literature pertaining to modern portfolio theory, traditional portfolio theory (fundamental and technical analyses), and behavioural finance theory. The implication of the efficient market hypothesis in relation to all the portfolio management theories is also presented and discussed. In line with a positivist paradigm, the survey research methodology, which combines both qualitative and quantitative aspects, was adopted. The instrument used for data collection was a questionnaire, which was found to be reliable and valid for this research. The questionnaire encompassed the Lickert scale to measure the data. The results of the analysis were interpreted using descriptive statistics. The results of this research suggest that modern portfolio theory does not play a significant role in the management of portfolios and security evaluation in South Africa. South African asset managers regard fundamental analysis as the most significant method of security evaluation in the management of portfolios. Technical analysis and econometric models are regarded as playing a moderate role and complement fundamental analysis whilst behavioural finance models play the least role. This research recommends an integrated portfolio management strategy that incorporates MPT, traditional portfolio theory and behavioural finance models to enhance investor value and protection.
- Full Text:
- Date Issued: 2005
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