More and more enterprises plan to switch their legacy system to service-oriented architecture (SOA). SOA, the focus of recent software-engineering, modulizes the IT components as “services” which could be re-jointed with each other flexibly and reused to avoid building parts repeatedly. This methodology also yields network externalities (Katz and Shapiro 1986; Markus 1987) as a number of services are integrated. An enterprise could increase the number of services to earn network externalities but such benefits come with risks. / This study aims to evaluate the investment of SOA and justifies the switch of current systems to SOA. Since SOA investment is usually a long-term and risky project for most enterprises, uncertainty becomes an important evaluation factor of an SOA project. This research applies the real option approach to evaluate an SOA switching project which majorly justifies the uncertainties, and use Monte-Carlo simulation to do the option pricing work. We consider three components of uncertainty in the model– risk, exercise time and number of connecting services for reusing- and evaluate how the uncertainty relates to the value of an SOA project. Finally, this research deduces the investment strategies under uncertainties, and describes what advantages for real option SOA has which are SOA could reduce the investment friction.

我國勞工退休金新制自2005年7月1日開始實施，由過去的確定給付制改為具有確定提撥特色的「個人帳戶制」。對於勞工而言，確定提撥制和過去確定給付制不同之處在於承擔退休金投資風險的責任將由雇主轉由個人承擔。如何透過退休機制的設計以降低退休金的投資風險是近年來的重要議題，因此本文主要從個人偏好與風險的觀點探討保證投資收益率制度與制度轉換選擇權等兩個降低確定提撥制投資風險的重要配套措施。 在本論文的第一篇研究中發現，資產配置與國際投資對保證成本的影響頗大，在個人可選擇資產配置的情況下，高投資風險的資產選擇將造成政府未來龐大的或有負債。為了解決政府保證成本過高造成代內與代間的財富移轉，本文從使用者付費與個人效用的觀點探討保證投資收益率制度的設計，發現藉由設立保證投資收益上限可提升風險趨避者、損失趨避者與後悔趨避者等偏好下的預期效用，且能降低個人管理下方風險所需的提撥成本與退休計畫參加者所需繳交的保證費用，故建議政府可將投資收益率上限納入保證投資收益率制度，供退休計畫參加者選擇合於本身偏好的保證收益率上限。 在近來許多國家的公、民營退休體系由過去以確定給付制改為確定提撥制，為了降低在確定提撥制下的退休金投資風險，在美國的佛羅里達州之公務人員退休體系中，存在著可供個人選擇是否轉換到確定給付制的機制。在我國勞退新制中除了從過去的確定給付制改為確定提撥制外，亦輔以「年金保險制」供勞工選擇與轉換，若年金保險制具有確定給付制的特徵，則勞工等於是擁有一個從確定提撥轉換轉到確定給付制的選擇權，因此制度選擇權的探討對我國而言亦是相當地重要。在本論文的第二篇研究中發現，當風險趨避程度越高則轉換至確定給付制的機率越高，轉換到確定給付制的高峰期會出現在開始工作的初期與屆臨退休之際等兩段期間。隨著工作期間的延長，個人轉換到確定給付制的機率越低，但仍可有效地提升退休金的所得替代率與達到降低退休金下方風險的效果，在加入退休制度初期不得轉換的限制之後，會降低轉換到確定給付制的機率。 / The Labor Retirement Pension Act enacted in 2005 introduced defined contribution (DC) pension plan for substituting the traditional defined benefit (DB) pension plan. In the defined contribution pension plan, the investment risk is transferred to the participants. However, the design of rate of return guarantee makes the investment risk less severe for participants. In the first essay, we find that the asset allocation and foreign investment have large impact on the guarantee cost: the high risky investment may result in large potential liability of the government in the future if participants have the investment portfolio choice. This study develops a framework to analyze design of rate of return guarantee from the financial engineering and user paid principle view. We find that the cap of investment return guarantee not only increases the expected utility of risk aversion, loss aversion and regret aversion, but also decreases the contribution cost to participant associated with managing the downside risk. Around the world, the defined contribution (DC) plans have been the primary trend of pension reform in the both public and private sector. In an attempt to decrease the investment risk associated with DC plan, the public employees are provided with an option to buy back DB plan in the Florida State of U.S.A. In the second essay, we find that the higher level of risk aversion is, the higher probability to buy back DB plan is. During the employee’s early years of service and as the employees near retirement, the probability to exercise the option is the highest. The probability to exercise the option is decreasing with the years of service being increasing; the option also increase the pension replacement rate as well as decrease the downside risk of pension. The probability to exercise the option is lower, when the option to buy back the DB plan is prohibited during the employee’s early years of service.

勞退新制即將在 94年 7 月 1 日起正式實施，在新的退休金體系下，勞工可由舊制的確定給付制轉換到擁有資產配置與投資決策權利的確定提撥制。台灣的勞退新制可分為兩種退休金制度供勞工選擇－個人帳戶制及其他年金制。確定提撥制與確定給付制在本質上有諸多的差異性，分別具有不同的優缺點，在本文的假設下，轉換選擇權存在於個人帳戶制與其他年金制之間。另外，在期望達到勞工退休金財富極大化的目標下，勞工會選擇在適當的時點，由個人帳戶制轉換到其他年金制。 　　雖然本文是採定值模型來分析，但是提供一個直觀上充分的洞悉與表徵，來解釋勞退新制下之個人帳戶制及其他年金制之間，若存在一最適轉換時點，其在經濟意涵中所表示之抵換關係與經濟價值為何。本文建構一個退休金財富極大化之模型，結合數值模擬的方法來分析其要點。研究結果發現，最適轉換時點之衡量，是由兩種制度下的變動率，而非帳戶內金額之大小來決定；此外，年金精算現值計算經折現後的給付率和剩餘工作年數，對於勞動工作者的選擇也屬重要變數之一。另外，本文針對年輕的勞工，在不同投資報酬率環境下，計算出兩種制度間抵換的價值；最後，本文也探討了執行轉換選擇權對於不同年紀的勞動工作者影響的幅度。總而言之，本文希望提供勞動工作者在勞退新制下，一個退休金財富配置最適化的準則，及執行轉換選擇權時參考的方針。 / The newly Labor Pension Act will be carried out in 2005 soon. Under this new pension system, employees will be given the choices of converting their traditional defined benefit (DB) pension plan into an individual-account defined contribution (DC) pension plan with full control over assets allocation and investment decisions. Under DC pension plan in Taiwan, there are two types of pension plan- Individual Account System and Commercial Pension Plan System- for employees to choose. DC and DB pension plan are totally different in essences, so on the basis of our assumptions, switch options will exist among Individual Account System and Commercial Retirement Plan System. Thus, in order to maximum employees’ retired wealth, employees might choose the optimal time to convert Individual Account System into Commercial Pension Plan System. Although our model is deterministic in nature, we believe that it provides an intuitive insight about switch options. We find not only the optimal switch time between Individual Account System and Commercial Retirement Plan System but also the “trade-off” economic values. This paper designs a model of maximizing retired wealth and makes numerical simulation to analyze optimal switch time. We find it is the “rate of change” of these two different pension systems affects the times for employees to exercise switch options. Besides, both the payment-rate scaled present value of the DB pension annuity and the retirement horizon are significant parameters in our analysis. Third, we also calculate the threshold investment returns between Individual Account System and Commercial Pension Plan System under various investment environments. Finally, we also contrast the effects of exercising switch options between younger and older employees. In short, we want to provide some principles for employees to make the optimal retired wealth allocation under Newly Labor Pension Act, then exercise switch options at the proper time.