針對各國普遍面臨人口結構逐漸老化、退休人口增加問題，世界銀行曾提出應建立至少三層保障的養老制度之呼籲；而我國迄今尚未建構出一套全面性之老年經濟生活安全保障制度，現有退休制度係依國民職業身分作為區分基礎。近幾年政府財政日趨惡化，加以國內經濟景氣不佳，失業率節節升高，公務人員由於工作與薪資相對較為穩定，其退休給付亦較完備；因此，遂引起各界對公務人員退休給付及其條件之合理及公平性的諸多討論。而公務人員退撫基金管理良窳，除攸關公務人員退休權益，亦牽涉政府最後給付責任，在政府可用資源相對減少下，如何防範政治力介入，暨因應現有制度與管理上的若干缺失，避免未來發生嚴重財務危機，均為本研究之重點。 本研究採取文獻探討、比較研究法，並輔以德菲爾法（Delphi Method）、問卷調查等方法，就公平及管理角度檢視現行公務人員退休制度所存在之缺失及具體改進之道。研究結果發現大多數受訪者認為我國對老年經濟生活安全之保障，與個人從事職業別有很大關聯；除軍公教人員以外之其他職域與非工資勞動者的老年經濟生活保障普遍不足，故在制度比較上常衍生出差別性待遇公平性問題；而退撫基金經營決策又常有政治力介入，特別是政經情勢不穩定時，除非逐漸民營化，政府僅擔任監督者角色，否則既使修法明定政府干預、挪用基金等限制條文，只要仍維持現行制度精神，由政府管理，便很難防範政治力介入該基金之實際運作。 基此，本研究提出下述幾點建議：1.政府應致力提升其他職域（身分）人員之老年經濟生活安全保障；2.公務人員請領月退休金年齡條件應予以延後，並適度降低現行給付水準；3.研議增訂彈性退休規定，並研酌展期年金及減額年金之可行性；4.宜朝向「確定給付制」兼採「確定提撥制」混合制方向發展，並逐步提高「確定提撥制」比例及採個人退休金帳戶制；5.修法明確規範退撫基金提撥率之調整機制，以健全基金財務結構；6.宜逐步增加退撫基金國外投資配置比例；7.應研酌未達法定最低收益由國庫補足差額之規定，以免否對資產長期配置造成扭曲；8.對於有價證券之投資應改採市價法評價，以反映基金資產真實價值；9.加強退撫基金財務資訊公開，以利全體投保人之監督；10.現行基金管理與監理組織，可研酌精簡合併為一獨立專業監理機關。11.修法使退撫基金經營管理趨向私有化與自由化。 / To confront the ever growing ageing trend and consequent retirement tide, the World Bank has contended three pillars of old age security over the past few years. The ROC government, however, has not yet launched a national pension scheme to ensure the elderly economic security so far although the Plan has been worked out for some time. The country is currently adopting a retirement system based on people’s occupation. Civil servants all along enjoy relatively sound and stabilized retirement benefits even under the aggravating financial difficulties and the economy recession. Together with the increasing unemployment rate, this phenomenon has augmented a great deal of discussion with regard to its fairness. In addition, since the government has played significant role in terms of Pension Fund Management, how to prevent political intervention and avoid mismanagement particularly during economic crisis certainly deserve close scrutiny. In light of the aforementioned, this study, based on literature review, survey, and Delphi, focuses on the fairness and management perspectives of the existing pension system for civil servants. It is found that most interviewees agree that civil servants comparatively enjoy better retirement benefits than the rest of the population since the current pension system has been designed on occupational basis. It is further observed by the interviewees that political intervention does exist in terms of Pension Fund Management especially during economic recession. It is thus harbored that perhaps only through “privatization”, such intervention can come to its stop. The study, among other things, suggests the followings: 1.A national pension scheme covering all people is required. 2.Postponing the age of receiving annuity from the current 50 to a later age and reasonably cutting off some civil servants’ pension benefits need to be addressed. 3.Adding flexibility to current civil servants’ retirement system is worth pondering. 4.Working out a system blending together “defined benefit” and “defined contribution” in which the proportion of “defined contribution” should be gradually enlarged. Thoughts with regard to “individual account” should also be studied. 5.Adjusting the insurance fee for pension fund is necessary in order to ensure financial viability. 6.Bigger proportion of pension funds’ overseas investment should be allowed. 7.Investment in securities should be evaluated with market price to reflect the actual value of fund assets. 8.Pension funds management report should be released to the general public for supervision. 9.Professional pension fund supervision mechanism has to be established. 10.Law provisions as to privatize and liberalize the pension fund need to be worked out.

本文於確定提撥退休金制度下，探討基金經理人如何決定最適資產策略規避薪資所得及通貨膨脹之不確定風險，求得期末財富效用期望值極大化。本研究首先擴展Battocchio與Menoncin (2004)所建構之資產模型，我們不僅探討來自市場之風險，同時考量薪資所得、通貨膨脹與費用率之不確定性，研究其對最適資產配置行為的影響，建構隨機控制模型，以動態規劃方法求解Hamiltonian方程式，研究結果顯示，我們可利用五項共同基金分離定理來描述投資人之最適投資決策：短期市場基金、狀態變數避險基金、薪資所得避險基金、通貨膨脹避險基金與現金部位。數值結果顯示，股票持有部位中通貨膨脹避險基金佔有最大的成份，債券持有部位中通貨膨脹避險基金與狀態變數避險基金佔有最大的成份。 關鍵字：確定提撥、薪資的不確定性、通貨膨脹、隨機控制、動態規劃 / In this study, we investigate the portfolio selection problem in order to hedge the labor income and inflation uncertainties for defined contribution (DC) pension schemes. First, we extend the previous work of Battocchio and Menoncin (2004) that allowed the state variables (i.e., the risks from the financial market) and a set of stochastic processes to describe the inflation, labor income and expense uncertainties. A five-fund separation theorem is derived to characterize the optimal investment strategy for DC pension plans to hedge the labor income and the inflation risks. Second, by solving the Hamiltonian equation in the three-asset framework, we show that the optimal portfolio consists of five components: the myopic market portfolio, the hedge portfolio for the state variables, the hedge portfolio for the inflation risk, the hedge portfolio for the labor income uncertainty and the riskless asset. Then we explicitly solve the optimal portfolio problem. Finally, the numerical results indicate that the inflation hedge portfolio comprises the overwhelming proportion of stock holdings in the optimal portfolios. In addition, the inflation hedge portfolio and the state variable hedge portfolio constitute the overwhelming proportions of bond holdings. Keywords: defined contribution; salary uncertainty; inflation; stochastic control; dynamic programming.

現行各國的退休金計畫逐漸地由確定給付制轉變為確定提撥制。這表示投資的風險由原本退休金計畫的發起者(雇主)轉移到了參與者(員工)的身上。為了減少每個確定提撥制計畫參與者的投資風險，本文中採用退休時所得替代率為預估的目標，藉由模擬與最適化的方法找到最適投資策略與最適提撥率。 能反映出時間性的隨機模型在精算科學的領域是日漸重要，本文試著藉由隨機性的變化來估計代替以往精算上各種假設下所求得的負債。本文藉由隨機模擬的方式，得到各種資產在市場上或者是經濟上的價值來建構相關投資標的之報酬率，並利用動態隨機規劃模型去改善財務上避險以及資產負債管理。此外，為了避免模擬分析時間過長的問題，本文採用了情境抽樣的方法去改善電腦模擬分析計算時的效率。 我們主要得到以下結論： (一)確定提撥制下的負債受薪資水準波動的影響，所以此時會持有較 多的指數連結型債券以反應薪資水準及通貨膨脹的影響。整體投 資的結果與Vigna & Haberman (2001) 文中的結果及實務上生命 週期型態(lifestyle)投資方式呈現相同的現象。 (二)考慮每期下跌風險(downside risk)時，期中的投資可能會偏向 於投資風險較高的股票。在每年觀察下跌風險的情況下其投資因 為必須考慮避免每一年的下跌風險，需要比每五年觀察下跌風險 的情況做風險較大的投資，以達到其目標。 (三)在本文的調整投資組合策略下，因為調整次數不多，所以在考慮 交易成本的情況，當交易成本很小時對於整體的最適化資產配置 與最適化提撥率的影響是很小的。在本文的調整投資組合策略 下，交易成本的影響只有在交易成本非常大的情況下才能看得出 來。 (四)均勻抽樣法抽出的400組情境幾乎可以完全的代替4000組情境， 其結果可以看出與未抽樣相同的生命週期型態(lifestyle)投資 方式。而隨機抽樣法的結果雖然也可看出趨勢，但準確性相對於 均勻抽樣法仍稍嫌不足，並不適合用來代替原先的4000組情境。 / A shift from defined-benefit pension plan towards defined-contribution pension plan is currently popular around the world. This means that a serious investment risk transfers from defined-benefit sponsors to the individual members of defined-contribution plans. In order to reduce the risk of individual DC member, we investigate the methodology of finding the optimal contribution rate and asset allocation to reach a certain target of the retirement replacement rate in this paper. Stochastic processes are getting more important to the field of actuarial science. Instead of trying to approximate liabilities by a single deterministic set of actuarial assumption, we seek to take account of market or economic valuation for both assets and liabilities using stochastic simulation. We applied dynamic stochastic programming models to improve financial hedging and asset liability management. Moreover, in order to avoid the problem of time-consuming, we use scenario sampling method to improve the efficiency of computer calculation. We draw four conclusions from our investigations： (1)We will hold more assets in indexed-linked bonds because the pension liability is highly related to the wage- index and inflation rate. The optimal investment strategy is very like the so called "lifestyle" investment strategy. (2)When we consider downside risk, we should hold more risky equities. The investment strategy is more risky when we consider downside risk every year than every 5 years. (3)Under our rebalancing strategy, if the transaction cost is small, the influence on the investment strategy and contribution rate is small. We can see the influence of the transaction cost in a situation that the transaction cost is very big only. (4)There are almost no different between uniform sampling scenarios and original simulation scenarios, so uniform sampling scenarios may replace the original simulation scenarios perfectly. And random sampling method is unsuitable to replace the original simulation scenarios.

Asset allocation is the most influential factor driving investment performance. While researchers have made substantial progress in the field of asset allocation since the introduction of mean-variance framework by Markowitz, there is little agreement about appropriate portfolio choice for multi-period long horizon investors. Nowhere this is more evident than trustees of retirement plans choosing different asset allocation strategies as default investment options for their members. This doctoral dissertation consists of four essays each of which explores either a novel or an unresolved issue in the area of asset allocation for individual retirement plan participants. The goal of the thesis is to provide greater insight into the subject of portfolio choice in retirement plans and advance scholarship in this field. The first study evaluates different constant mix or fixed weight asset allocation strategies and comments on their relative appeal as default investment options. In contrast to past research which deals mostly with theoretical or hypothetical models of asset allocation, we investigate asset allocation strategies that are actually used as default investment options by superannuation funds in Australia. We find that strategies with moderate allocation to stocks are consistently outperformed in terms of upside potential of exceeding the participant’s wealth accumulation target as well as downside risk of falling below that target by very aggressive strategies whose allocation to stocks approach 100%. The risk of extremely adverse wealth outcomes for plan participants does not appear to be very sensitive to asset allocation. Drawing on the evidence of the previous study, the second essay explores possible solutions to the well known problem of gender inequality in retirement investment outcomes. Using non-parametric stochastic simulation, we simulate iv and compare the retirement wealth outcomes for a hypothetical female and male worker under different assumptions about breaks in employment, superannuation contribution rates, and asset allocation strategies. We argue that modest changes in contribution and asset allocation strategy for the female plan participant are necessary to ensure an equitable wealth outcome in retirement. The findings provide strong evidence against gender-neutral default contribution and asset allocation policy currently institutionalized in Australia and other countries. In the third study we examine the efficacy of lifecycle asset allocation models which allocate aggressively to risky asset classes when the employee participants are young and gradually switch to more conservative asset classes as they approach retirement. We show that the conventional lifecycle strategies make a costly mistake by ignoring the change in portfolio size over time as a critical input in the asset allocation decision. Due to this portfolio size effect, which has hitherto remained unexplored in literature, the terminal value of accumulation in retirement account is critically dependent on the asset allocation strategy adopted by the participant in later years relative to early years. The final essay extends the findings of the previous chapter by proposing an alternative approach to lifecycle asset allocation which incorporates performance feedback. We demonstrate that strategies that dynamically alter allocation between growth and conservative asset classes at different points on the investment horizon based on cumulative portfolio performance relative to a set target generally result in superior wealth outcomes compared to those of conventional lifecycle strategies. The dynamic allocation strategy exhibits clear second-degree stochastic dominance over conventional strategies which switch assets in a deterministic manner as well as balanced diversified strategies.

Made available in DSpace on 2009-11-18T19:00:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2001 / o trabalho discute os fatores que condicionaram a migração de planos de beneficios entre os Fundos de Pensão localizados no Estado do Espírito Santo. O mais antigo modelo de plano de beneficios implantado no Brasil, o plano de beneficio definido, tem características bastante vantajosas aos participantes, pois as empresas patrocinadoras assumem os riscos de desequilíbrio do plano, e os beneficios futuros são assegurados aos participantes. O segundo modelo, mais recente no país, tem como característica principal o fato de que o participante assume os riscos do plano, e os beneficios futuros dependem de diversos fatores, como rentabilidade, tempo de participação, entre outros, deixando de existir garantia aos participantes. Apesar disso, os Fundos de Pensão tem implantado processos de migração de planos de beneficio definido para contribuição definida com sucesso. O texto procura identificar as razões e conseqüências da migração, estabelecendo correlações entre os dois modelos, identificando suas diferenças e semelhanças, o papel exercido pelas empresas patrocinadoras e a estratégia de convencimento dos participantes. Pretende-se que as reflexões sobre esse processo possam contribuir para que os Fundos de Pensão e outros pesquisadores interessados possam ter um nível maior de compreensão e fundamentação sobre o assunto. / This dissertation discusses the factors that have created the framework for the migration of the pension plans among the pension funds in the state of Espirito Santo. The first benefit plan model in Brazil, the defined benefit plan, has many advantages for the participant. Their risks are supported by the sponsor of the plan, and future benefits are assured to the participants. The second model, more recently introduced in the country, has its main point in the fact that participants have to bear the risks, and future benefits depend on many factors like the historical performance of the plan and time of participation, and there is no guaranty to the participants. Regardless these facts, pension funds have adopted successful processes for the migration from defined benefits plans to defined contribution plans. This text identifies reasons and consequences of those process of migration, establishing correlations, differences and similarities between the two models, and the role of the sponsors and their strategies in persuading the participants. We intend to raise questions upon this process, in order to contribute for a greater levei of comprehension of the issue.

La présente thèse s'intéresse à trois acteurs du financement des régimes de retraite : le législateur, l'assureur et l’individu. Dans un environnement en proie à un comportement déviant du marché financier et à des évolutions démographiques défavorables, le rôle de ces parties prenantes doit impérativement faire l’objet d’une réévaluation pour relever le défi de la pérennité du financement des retraites. L’étude de la règlementation et de la conception des régimes a été réalisée en intégrant des caractéristiques types du futur paysage des retraites, telles que le poids de plus en plus important du risque assumé par l’individu ou l’éventuelle participation d'investisseurs boursiers dans l’offre de contrats. Les conclusions de cette étude permettent de dégager des orientations en vue de la gestion du risque de longévité pour les individus, une évaluation de l’attrait de l’exposition au risque de longévité pour les investisseurs, des informations sur l’élaboration des contrats pour les assureurs ainsi que des propositions, pour les décideurs politiques, de mesures règlementaires favorisant la durabilité du paysage des retraites. / This dissertation examines three stakeholders in pension finance: the individual, the policymaker, and the pension provider (e.g., an insurer or a pension fund). In a setting beset by unforseen financial market circumstances and demographic changes that disfavor financial security in retirement, a re-evaluation of these stakeholders’ role is necessary. We explore the regulation and design of retirement plans by incorporating features that characterize the future retirement landscape, such as the increasing burden of risk borne by the individual, and the potential involvement of market investors in the provision of retirement contracts. The implications of our findings encompass guidance for individuals in managing longevity risk, evaluation of the appeal of longevity risk exposure to investors, insights on contract design for the insurer, and proposals to the policymaker on regulatory measures that foster a sustainable retirement environment.

近年來有很多關於退休金計畫的研究主要在探討從確定給付計畫(defined benefit plan)轉向確定提撥計畫(defined contribution plan)趨勢的影響。而這些早期的研究(Clark and McDermed(1990 and 1993), Gustman and Steinmeier(1992), Ippolito(1985, 1986, 1993, and 1997), and Kruse (1995); Papke(1994, 1996)and Papke, Petersen and Poterba(1996)主要是利用計畫個數的改變或者是計畫參與者人數的增減來作為衡量此一趨勢影響力的指標。然而，這兩項指標從退休收入多寡的觀點來看，卻無法反應此一趨勢對於員工福利的影響程度。Wang andVanDerhei(2000)利用了「雇主退休金成本」的新概念，探討此一趨勢的影響。而本篇論文將要延續Wang and VanDerhei(2000)的研究，藉由衡量雇主慷慨程度的改變，進一步分析此一趨勢對於員工未來退休收入的影響程度。為了檢視雇主退休金慷慨度是否有隨著時間以及環境變化而有所不同，我們利用OLS迴歸模型來分析在兩段期問中（1985年與1996年）雇主退休金慷慨度的變化。結果發現在確定給付計畫及401(k)計畫之下，退休金計畫存在的時間愈長以及工會的支持對於雇主慷慨程度都有正面的影響。在財務變數方面，我們則是發現不論哪一種型態的退休金計畫，稅前收入金額的多寡對於雇主慷慨程度均具有正面的影響。此外，利用Chow Test，我們發現確定給付計畫在1985年和1996年的確具有結構上的改變，進一步分析之後，發現退休金計畫存在時間愈長、工會的支持、金融相關產業、固定資產佔總資產的比例以及稅前收入金額的多寡對於1996年確定給付計畫下之雇主退休金慷凱度的正向影響遠大其對於1985年的確定給付計畫。在員工退休福利上，我們則是發現401(k)計畫的雇主相對提撥率在過去20年有明顯地成長，這意味著401(k)計畫下的員工在過去20年裡的退休福利有明顯的增加。 關鍵字：退休金趨勢、雇主退休金慷慨度、確定給付計畫、確定提撥計畫、401(k)計畫 / Much debate has devoted in recent pension literature to discuss the impacts of current pension trend toward defined contribution(DC) plans, especially the substitution effect between 401(k) and other pension plans. However, the“generosity”of the employer pension plan deserves little attention. This paper analyzes the impacts of the effects of this trend on workers' future retirement income by measuring the changes of employers' pension generosity. We construct a panel data of firms that sponsor at least one pension plan in 1985 and compare the changes of their pension generosity for DB, DC and 401(k) plans between 1985 and 1996. OLS Regression Models are adopted to analyze the generosity of employers' primary plan and supplemental plan and Chow test is conducted to test the structural changes between 1985 and 1996. Our results find that plan age and union status have positive impacts on employers' generosity ofDB and 401(k) plans. For financial variables, pretax income is an important consideration to employers' generosity disregarding the type of plan. In addition, we find that there was a structure change ofDB plans between 1985 and 1996 and that union status,plan age, financial etc. industry, proportion of fixed assets and pretax income have greater positive impacts on employers' generosity ofDB plans in 1996 than in 1985. For employees' retirement income, the matching rates have grown over the last two decades and this stands for that employees covered by 401(k) plans have received better retirement benefit over the last two decades. Key words: Pension trends; Employers' generosity; Defined benefit plan; Defined contribution plan; 401(k) plan

本研究探討長期投資人之最適資產配置問題，並著重於通貨膨脹風險之分析。第一部份討論確定提撥退休金制度下，機構投資人或高所得自然人如何擬定投資策略規避通貨膨脹風險，達到極大化期末財富效用期望值。此研究擴展Battocchio與Menoncin (2004)所建構資產模型，不僅探討市場風險，亦考量通貨膨脹不確定性與基金費用誘因、下方風險保護兩機制，研究對資產配置行為之影響，並依動態規劃方法求得投資策略公式解。第二部份則強調下方風險之重要性，檢視在最低保證收益下，長期投資人跨期資產配置之財富管理議題，並回顧Deelstra et al.(2003)之模型架構，依平賭方法求得投資策略公式解，研究結果顯示基金投資策略可表示為最適CRRA(γ,T)型態共同基金與最低收益避險之組合。另一方面，如何估計通貨膨脹風險亦為本文強調之重點。Campbell和Viceira (2001)首次納入通貨膨脹風險並探討跨期投資議題，結論市場缺乏通貨膨脹連動投資標的時，投資人將減碼長期債持有比例。Brennan和Xia (2002)假設通貨膨脹率服從Ornstein-Uhlenbeck過程，結論投資人之避險需求隨持有債券到期日與投資期限改變。但以上結論未將通貨膨脹學習機制納入模型，因此，在第三部份提出依學習機制修正之投資策略可顯著增加財富效用，並分析在不同參數設定下，學習機制對於期末財富效用之影響。 / In this study, we study three essays of asset allocation problem for long term investors, which means that in this discourse we emphasis the importance of inflation risk. In the first topic, we derive the dynamic optimal investment strategy of the defined contribution pension schemes which include two mechanisms of partial floor protection and incentive fees and their benchmarks. We find investors should hold high proportion of stock index fund to hedge the inflation risk; moreover, the ratio of incentive fees to the setting of benchmark will change the optimal investment trend of underlying assets. In the second topic, we introduce the optimal investment portfolio with minimum guarantees and show that the fund manager should adjust the optimal weights of underlying assets with the ratio of the guarantee fund's value to the value of fund. Finally, this work focuses on how to precisely predict the dynamics of inflation rate. We apply learning method to adjust the prediction of inflation process and we use numerical analysis to study the effect of learning mechanism under different parameter setting.

退休金是退休人未來生活的依靠，確保在退休後能得到適足的退休給付，政府在退休金上實施保證收益制度，此制度為最低保證利率與投資報酬率連結。本文探討退休金給付標準為確定提撥制，當退休金的投資報酬率是根據其連結之股價指數的表現來計算時，股價指數報酬率的模型假設為馬可夫調控跳躍過程模型，考慮市場狀態與布朗運動項、跳躍項的跳躍頻率相關，即為Elliot et al. (2007) 的模型特例。使用1999年至2012年的道瓊工業指數與S&P 500指數的股價指數對數報酬率作為研究資料，採用EM演算法估計參數及SEM演算法估計參數共變異數矩陣。透過概似比檢定說明馬可夫調控跳躍過程模型比狀態轉換模型、跳躍風險下狀態轉換模型更適合描述股價指數報酬率變動情形，也驗證馬可夫調控跳躍過程模型具有描述報酬率不對稱、高狹峰及波動叢聚的特性。最後，假設最低保證利率為固定下，利用Esscher轉換法計算不同模型下型I保證之確定提撥制退休金的評價公式，從公式中可看出受雇人提領的退休金價值可分為政府補助與個人帳戶擁有之退休金兩部分。以執行敏感度分析探討估計參數對於馬可夫調控跳躍過程模型評價公式的影響，而型II保證之確定提撥制退休金的價值則以蒙地卡羅法模擬並探討其敏感度分析結果。 / Pension plan make people a guarantee life in their retirement. In order to ensure the appropriate amount of pension plan, government guarantees associated with pension plan which ties minimum rate of return guarantees and underlying asset rate of return. In this paper, we discussed the pension plan with defined contribution (DC). When the return of asset is based on the stock indices, the return model was set on the assumption that markov-modulated jump diffusion model (MMJDM) could the Brownian motion term and jump rate be both related to market states. This model is the specific case of Elliot et al. (2007) offering. The sample observations is Dow-Jones industrial average and S&P 500 index from 1999 to 2012 by logarithm return of the stock indices. We estimated the parameters by the Expectation-Maximization (EM) algorithm and calculated the covariance matrix of the estimates by supplemented EM (SEM) algorithm. Through the likelihood ratio test (LRT), the data fitted the MMJDM better than other models. The empirical evidence indicated that the MMJDM could describe the asset return for asymmetric, leptokurtic, volatility clustering particularly. Finally, we derived different model's valuation formula for DC pension plan with type-I guarantee by Esscher transformation under rate of return guarantees is constant. From the formula, the value of the pension plan could divide into two segment: government supplement and employees deposit made pension to their personal bank account. And then, we done sensitivity analysis through the MMJDM valuation formula. We used Monte Carlo simulations to evaluate the valuation of DC pension plan with type-II guarantee and discussed it from sensitivity analysis.

員工持股計畫是由財經律師Louis Kelso所創，在美國已行之多年，廣為美國企業所採。最早的員工持股計畫是一種為了和平地從資本家手中移轉資本給員工、縮減貧富差距的工具。為了使這個計畫可以持續有效地運作下去，立法者將員工持股計畫為退休金計畫的一種，使員工必須長期持有股票，直到退休。然而在實務運作上，員工持股信託經常被運用為防止敵意併購的工具。尤有甚者，某些公司內部人會利用員工持股計畫為自己取得大量資金、移轉投資風險,但仍可保留對於公司的控制力。這些行為都有可能對股東及員工造成不利的影響，但在現行法制下，只能仰賴司法者透過判決保護這些經濟及資訊上的弱勢族群。 在台灣，員工持股計畫雖然已廣為許多企業所採用，但是發展了將近20年，只能成為另一種員工持有股票的工具。員工擁有的股票數量並不足以使其在股東會上贏得一個受公司內部人重視的地位，也不足以倚賴這些股票作為退休金之用。這種規模上的差異是台美員工持股計畫最關鍵的不同點。小規模雖然使員工持股計畫帶來的優勢少了許多，但相對地也減低許多代理成本，至今未有員工持股計畫侵害大量員工利益的事件爆發。然而這不表示員工持股計畫在台灣就是個可以被忽略的問題，若能在未來建立一套有效率的立法制度，使員工持股計畫的規模擴大，員工將可因此享受到更多公司盈餘，並且使其退休生活受到保障。相對地，參考美國員工持股計畫的問題後，也可以預先設想未來可能發生的弊端，未雨綢繆。本文相信，一個有效率的員工持股計畫，可以實現解決貧富不均的理想。 / Employee stock ownership plan (ESOP) which is created by Louis Kelso is brought to practice for many years. Many enterprises use it as their retirement pension plan. The earliest employee stock ownership plan to transfer the capital frome capitalists to labors and reduce the disparity between the rich and the poor.In order to make the plan work out continueously and effectively, the legislator devise ESOP as a pension fund which makes employee own stock chronically until they retires. However, in practice, ESOP is usually exercised for preventing hostile takeover. Moreover, some company insiders may use ESOP TTO get a great deal of capital and transfer the investment risk, but still own the controlling power to their company. This behaviors will cause some harmful effects to the shareholders and the employees, but in the current legal system,the only one we can depend is the judge who can protect the minority in the economic and the information. ESOP is exercised by many enterprises in Taiwan. But after 20 years, it can only become one of the tools which assist employees to acquire company stocks.The number of shares which employees owns can’t make them have a posi-tion which let the company insiders take account in the shareholder committee and have enough amounts for their retirement pensions.This disparity in scale is the keypoint what is different between Tiwan and the U.S. ESOP. Althoygh small scale makes the adventage of ESOP decrease, it reduce lots of agency costs. To this day, there’re not any events which injure the interests of employees by ESOP. Never-theless, it doesn’t mean that ESOP in Taiwan is a issue which can be neglected. If we can establish an efficient legal system and extend the scale of ESOP, employees can obtain more company interests and have a security of their retirement life.In the opposite, after researching the problem of the U.S. ESOP, we can assume the culpably misconduct which will happen in the future and repair the house before it rains。Ｉ believe that a efficient ESOP can realize the ideal to solve the problem of uneven distribution of the wealth.