The modelling of volatility has long been seminal to finance and risk management in general, as it provides information on the spread of portfolio returns. In order to reduce the overall volatility of a stock portfolio, modern portfolio theory (MPT), within an efficient market hypothesis (EMH) framework, dictates that a well-diversified portfolio should have a market beta of one (thereafter adjusted for risk preference), and thus move in sync with a benchmark market portfolio. Such a stock portfolio is highly correlated with the market, and considered to be entirely hedged against unsystematic risk. However, the risks within and between stocks present in a portfolio still impact on each other. In particular, risk present in a particular stock may spill over and affect the risk profile of another stock included within a portfolio - a phenomenon known as volatility spill-over effects. In developing economies such as South Africa, portfolio managers are limited in their choices of stocks. This increases the difficulty of fully diversifying a stock portfolio given the volatility spill-over effects that may be present between stocks listed on the same exchange. In addition, stock portfolios are not static, and therefore require constant rebalancing according to the mandate of the managing fund. The process of constant rebalancing of a stock portfolio (for instance, to follow the market) becomes more complex and difficult during times of financial distress. Considering all these conditions, portfolio managers need all the relevant information (more than MPT would provide) available to them in order to select and rebalance a portfolio of stocks that are as mean-variance efficient as possible. This study provides an additional measure to market beta in order to construct a more efficient portfolio. The additional measure analyse the volatility spill-over effects between stocks within the same portfolio. Using intraday stock returns and a residual based test (aggregate shock [AS] model), volatility spill-over effects are estimated between stocks. It is shown that when a particular stock attracts fewer spill-over effects from the other stocks in the portfolio, the overall portfolio volatility would decrease as well. In most cases market beta showcased similar results; this change is however not linear in the case of market beta. Therefore, in order to construct a more efficient portfolio, one requires both a portfolio that has a unit correlation with the market, but also includes stocks with the least amount of volatility spill-over effects among each other. / MCom (Risk Management), North-West University, Potchefstroom Campus, 2013

The modelling of volatility has long been seminal to finance and risk management in general, as it provides information on the spread of portfolio returns. In order to reduce the overall volatility of a stock portfolio, modern portfolio theory (MPT), within an efficient market hypothesis (EMH) framework, dictates that a well-diversified portfolio should have a market beta of one (thereafter adjusted for risk preference), and thus move in sync with a benchmark market portfolio. Such a stock portfolio is highly correlated with the market, and considered to be entirely hedged against unsystematic risk. However, the risks within and between stocks present in a portfolio still impact on each other. In particular, risk present in a particular stock may spill over and affect the risk profile of another stock included within a portfolio - a phenomenon known as volatility spill-over effects. In developing economies such as South Africa, portfolio managers are limited in their choices of stocks. This increases the difficulty of fully diversifying a stock portfolio given the volatility spill-over effects that may be present between stocks listed on the same exchange. In addition, stock portfolios are not static, and therefore require constant rebalancing according to the mandate of the managing fund. The process of constant rebalancing of a stock portfolio (for instance, to follow the market) becomes more complex and difficult during times of financial distress. Considering all these conditions, portfolio managers need all the relevant information (more than MPT would provide) available to them in order to select and rebalance a portfolio of stocks that are as mean-variance efficient as possible. This study provides an additional measure to market beta in order to construct a more efficient portfolio. The additional measure analyse the volatility spill-over effects between stocks within the same portfolio. Using intraday stock returns and a residual based test (aggregate shock [AS] model), volatility spill-over effects are estimated between stocks. It is shown that when a particular stock attracts fewer spill-over effects from the other stocks in the portfolio, the overall portfolio volatility would decrease as well. In most cases market beta showcased similar results; this change is however not linear in the case of market beta. Therefore, in order to construct a more efficient portfolio, one requires both a portfolio that has a unit correlation with the market, but also includes stocks with the least amount of volatility spill-over effects among each other. / MCom (Risk Management), North-West University, Potchefstroom Campus, 2013

現今世界趨勢已朝向全球整合的方向邁進，隨著科技日新，世界各國跨越地域隔閡，不論是在政治、經濟、科技、文化等各方面往來接觸愈來愈頻繁，中國大陸近年來與世界經貿關係連結更為緊密，同時亦對外開放直接投資，使跨國企業逐漸擴大進軍中國大陸之版圖，享受中國大陸豐沛之廉價勞動力。 然而，開放外人直接投資(Foreign Direct Investment, FDI)勢必為中國大陸相關之產業或總體經濟帶來某種程度之影響，儘管外人直接投資可帶來充沛之資本及先進之技術，但亦有可能加劇國內市場競爭，不利於本土廠商。 本文運用1998-2006 年「中國工業企業統計數據庫」中之電子業廠商，建構追蹤資料模型(Panel Data)，並運用隨機邊界法（stochastic frontier approach）估計中國大陸本資、台港澳資及外資企業生產效率，藉以衡量FDI之外溢效果。根據實證結果我們發現：中國大陸電子業之外人直接投資存在正向外溢效果及正向之技術移轉，顯示FDI之進入將有助於提升中國大陸電子業本土廠商之生產力。此外，我們同時發現FDI集中投資的結果將可能造成外溢效果的減低，除此之外，經濟區位亦是影響外人直接投資所帶來之外溢效果及技術移轉效果之重要因子之一。 / Global integration is the world trend nowadays. With the breakthrough of technology, the geographical barriers no longer exist. It would be much closer with other countries in many fields, such as politics, economics, technology and culture. In recent years, China has a closer economics and trades linkage with the world. As the results of openness to foreign direct investments, more and more multinational enterprises enter to China, expanding their scale and being benefited from the low-cost labor of China. China is benefited from the plentiful capital and advanced technologies of foreign direct investments; however, the openness to FDI might cause the competition which can aggravate in domestic market and hurt the domestic firms. The research uses the data of electronic firms from Chinese Industrial Enterprises Database. We apply panel data model and stochastic frontier approach to estimate the production efficiency of Chinese, Taiwanese, Hong Kong, Macanese and Other foreign enterprises. According to the empirical results, we discover that there are positive spill-over effects and technology transformation from foreign direct investments in Chinese electronic industry. These results indicate the entry of FDI will promote the productivity of Chinese electronic firms. Beside the positive results, we also discover the negative deduction stem in concentrated investments; furthermore, the spill-over effects and the technology transformation effects are affected by the economic location.