The Black-Litterman model is analyzed in three steps seeking to investigate, develop and test the B-L model in an applied perspective. The first step mathematically derives the Black-Litterman model from a sampling theory approach generating a new interpretation of the model and an interpretable formula for the parameter weight-on-views.  The second step draws upon behavioural finance and partly explains why managers find B-L portfolios intuitively accurate and also comments on the risk that overconfident managers state too low levels-of-unconfidence. The third step, a case study, concerns the implementation of the B-L model at a bank. It generates insights about the key-features of the model and their interrelations, the importance of understanding the model when using it, alternative use of the model, differences between the model and reality and the influence of social and organisational context on the use of the model. The research implies that it is not the B-L model alone but the combination model-user-situation that may prove rewarding. Overall, the research indicates the great distance between theory and practice and the importance of understanding the B-L model to be able to keep a critical attitude to the model and its output. The research points towards the need for more research concerning the use of the B-L model taking cultural, social and organizational contexts into account. / QC 20101202

Questa tesi è composta da 3 differenti lavori che ci confermano la prevedibilità degli extra rendimenti rispetto al mercato usando semplici strategie di portafoglio azionario utilizzabili sia dal semplice risparmiatore sia dall'investitore istituzionale. Nel primo capitolo è stata analizzata la profittabilità della contrarian strategy nel mercato azionario Italiano. In letteratura é stato già abbondantemente dimostrato che i rendimenti azionari sono caratterizzati da un’autocorrelazione negativa nel breve periodo e da un effetto di ritorno alla media nel lungo periodo. La contrarian strategy é utilizzata per trarre profitto dalla correlazione seriale negativa dei rendimenti azionari, infatti, vendendo i titoli che si sono rivelati vincenti nel passato (in termini di rendimento) e acquistando quelli "perdenti" si ottengono profitti inaspettati. Nel secondo paper, l'analisi si focalizza sulla strategia di portafoglio definita Dollar Cost Averaging (DCA). La Dollar Cost Averaging si riferisce a una semplice metodologia di portafoglio che prevede di investire una somma fissa di denaro in un'attività rischiosa a uguali intervalli di tempo, per tutto l'orizzonte temporale prefissato. Il lavoro si propone di confrontare i vantaggi, in termini di riduzione sostanziale del rischio, di questa strategia dal punto di vista di un semplice risparmiatore. Nell'ultimo capitolo, ipotizzando di essere un investitore istituzionale che possiede ogni giorno numerose informazioni e previsioni, ho cercato di capire come egli può usare tutte le informazioni in suo possesso per decidere prontamente come allocare al meglio il patrimonio del fondo. L’investitore normalmente cerca di identificare la migliore previsione possibile, ma quasi sempre non riesce ad identificare l’esatto processo dei prezzi sottostanti. Quest’osservazione ha condotto molti ricercatori ad utilizzare numerosi fattori esplicativi per ottenere un buona previsione. Il paper supporta l’esistente letteratura che utilizza un nuovo approccio per trasformare previsioni di rendimenti in scelte di gestione di portafoglio che possano offrire una maggiore performance del portafoglio.Partendo dal modello d’incertezza di Pesaran e Timmerman(1996), considero un cospicuo numero di fattori macroeconomici per identificare un modello predittivo che mi permetta di prevedere i movimenti del mercato tenendo presente i maggiori indicatori economici e finanziari e considerato che il loro rispettivo potere predittivo cambia nel tempo. / This thesis is composed by three different papers that confirm us the predictability of expected returns using different simple portfolio strategy and under different point of view (i.e. a generic saver and institutional investor). In the first chapter, I investigate the profitability of contrarian strategy in the Italian Stock Market. However empirical research has shown that asset returns tend to exhibit some form of negative autocorrelation in the short term and mean-reversion over long horizons. Contrarian strategy is used to take advantage of serial correlation in stock price returns, such that selling winners and buying losers generates abnormal profits. On the second chapter, the analyse is focused in another classic portfolio strategy called Dollar Cost Averaging (DCA). Dollar Cost Averaging refers to an investment methodology in which a set dollar amount is invested in a risky asset at equal intervals over a holding period. The paper compares the advantages and risk of this strategy from the point of view of a saver. Lastly, supposing to be an institutional investor who has a large number of information and forecasts, I tried to understand how using all them he decide with dispatch how to allocate the portfolio fund. When a wide set of forecasts of some future economic events are available, decision makers usually attempt to discover which is the best forecast, but in almost all cases a decision maker cannot identify ex ante the true process. This observation has led researchers to introduce several sources of uncertainty in forecasting exercises. The paper supporting the existent literature employs a novel approaches to transform predicted returns into portfolio asset allocations, and their relative performances. First of all dealing with model uncertainty, as Pesaran and Timmerman (1996), I consider a richer parameterization for the forecasting model to find that the predictive power of various economic and financial factors over excess returns change through time.

Many optimal stochastic control problems in finance can be formulated in the form of Hamilton-Jacobi-Bellman (HJB) partial differential equations (PDEs). In this thesis, a general framework for solutions of HJB PDEs in finance is developed, with application to asset allocation. The numerical scheme has the following properties: it is unconditionally stable; convergence to the viscosity solution is guaranteed; there are no restrictions on the underlying stochastic process; it can be easily extended to include features as needed such as uncertain volatility and transaction costs; and central differencing is used as much as possible so that use of a locally second order method is maximized. In this thesis, continuous time mean variance type strategies for dynamic asset allocation problems are studied. Three mean variance type strategies: pre-commitment mean variance, time-consistent mean variance, and mean quadratic variation, are investigated. The numerical method can handle various constraints on the control policy. The following cases are studied: allowing bankruptcy (unconstrained case), no bankruptcy, and bounded control. In some special cases where analytic solutions are available, the numerical results agree with the analytic solutions. These three mean variance type strategies are compared. For the allowing bankruptcy case, analytic solutions exist for all strategies. However, when additional constraints are applied to the control policy, analytic solutions do not exist for all strategies. After realistic constraints are applied, the efficient frontiers for all three strategies are very similar. However, the investment policies are quite different. These results show that, in deciding which objective function is appropriate for a given economic problem, it is not sufficient to simply examine the efficient frontiers. Instead, the actual investment policies need to be studied in order to determine if a particular strategy is applicable to specific investment problem.

Many optimal stochastic control problems in finance can be formulated in the form of Hamilton-Jacobi-Bellman (HJB) partial differential equations (PDEs). In this thesis, a general framework for solutions of HJB PDEs in finance is developed, with application to asset allocation. The numerical scheme has the following properties: it is unconditionally stable; convergence to the viscosity solution is guaranteed; there are no restrictions on the underlying stochastic process; it can be easily extended to include features as needed such as uncertain volatility and transaction costs; and central differencing is used as much as possible so that use of a locally second order method is maximized. In this thesis, continuous time mean variance type strategies for dynamic asset allocation problems are studied. Three mean variance type strategies: pre-commitment mean variance, time-consistent mean variance, and mean quadratic variation, are investigated. The numerical method can handle various constraints on the control policy. The following cases are studied: allowing bankruptcy (unconstrained case), no bankruptcy, and bounded control. In some special cases where analytic solutions are available, the numerical results agree with the analytic solutions. These three mean variance type strategies are compared. For the allowing bankruptcy case, analytic solutions exist for all strategies. However, when additional constraints are applied to the control policy, analytic solutions do not exist for all strategies. After realistic constraints are applied, the efficient frontiers for all three strategies are very similar. However, the investment policies are quite different. These results show that, in deciding which objective function is appropriate for a given economic problem, it is not sufficient to simply examine the efficient frontiers. Instead, the actual investment policies need to be studied in order to determine if a particular strategy is applicable to specific investment problem.

In the first essay, I decompose inflation risk into (i) a part that is correlated with real returns on the market portfolio and factors that determine investor’s preferences and investment opportunities and (ii) a residual part. I show that only the first part earns a risk premium. All nominal Treasury bonds, including the nominal money-market account, are equally exposed to the residual part except inflation-protected Treasury bonds, which provide a means to hedge it. Every investor should put 100% of his wealth in the market portfolio and inflation-protected Treasury bonds and hold a zero-investment portfolio of nominal Treasury bonds and the nominal money market account. In the second essay, I solve the dynamic asset allocation problem of finite lived, constant relative risk averse investors who face inflation risk and can invest in cash, nominal bonds, equity, and inflation-protected bonds when the investment opportunityset is determined by the expected inflation rate. I estimate the model with nominal bond, inflation, and stock market data and show that if expected inflation increases, then investors should substitute inflation-protected bonds for stocks and they should borrow cash to buy long-term nominal bonds. In the lastessay, I discuss how heterogeneity in preferences among investors withexternal non-addictive habit forming preferences affects the equilibrium nominal term structure of interest rates in a pure continuous time exchange economy and complete securities markets. Aggregate real consumption growth and inflation are exogenously specified and contain stochastic components thataffect their means andvolatilities. There are two classes of investors who have external habit forming preferences and different localcurvatures oftheir utility functions. The effects of time varying risk aversion and different inflation regimes on the nominal short rate and the nominal market price of risk are explored, and simple formulas for nominal bonds, real bonds, and inflation risk premia that can be numerically evaluated using Monte Carlo simulation techniques are provided.

『勞工退休金條例』於民國94年7月1日施行後，我國的勞工退休金經營管理模式有了根本上的變化。原來舊的制度下，退休金是以確定給付的方式經營，而在新制下則是以確定提撥的模式營運。新制由於不必考慮負債面，其資產配置的自由度相對來說大幅提高。然而，為了滿足法規『投資報酬率不得低於兩年期定存利率』之限制、以及達成高所得替代率的理想，退休基金的管理者將面臨追求短期穩定、以及長期高報酬兩項互為抵換目標的困難抉擇。 如何用一套較為實務上可行的方法，為新制下的退休基金擬定一套合乎其投資目標的長期策略性資產配置，是本研究所關心的課題。本文採用的方法是以多元蒙地卡羅模擬法（Monte Carlo Simulation），依據實際的資本市場假設來模擬整個投資組合期望報酬率的機率分配，並根據結果分析各種配置的優劣、提供決策者做參考。 本研究建議新制下退休基金的理想資產配置區間為：美國股票30%~40%、國際股票20%~30%、固定收益證券20%~30%、不動產5%~15%、以及私募股權0%~10%。其中，由於退休基金在成立前期的流動性需求較低，可以配置較高的比重於股票和不動產；後期則為了定期支付退休金、可以提高固定收益證券的比重。然而，本研究發現：『提高固定收益證券比重所帶來的短期穩定之加分、將不如其所犧牲的長期高報酬之減分』，因此不建議退休基金的管理人太早提高固定收益證券的投資比重。 此外，透過情境分析與敏感性分析，本研究認為長期而言，不動產是最為穩定、且又能同時達成長期高報酬目標的最佳投資標的。至於在戰略性配置上，如果基金管理者預期未來市場可能會出現長期動盪，則應該降低私募股權的比重。

許多新興風險隨著金融市場的變化而產生，以致於發生許多大型金融災害造成許多金融產業蒙受鉅額損失。而於金融市場尋求利潤已是金融產業重要的一環，有鑑於此，本論文提出ㄧ套完整的資產配置流程，利用技術指標建構綜合信號指標作為市場指標再選擇投資資產並估計、模擬、最適化投資權重並投資，以達到規避大型金融事件風險並獲取超額利潤。本論文亦嘗試不同股票評分指標、股票資產模型、結構模型、投資組合大小等組合，以找出最適合台灣股票支股票評分指標、資產模型以及投資組合大小。 本論文發現綜合信號指標作為市場指標可有效判讀金融事件的發生與結束時間，經由此指標判斷可獲得相當的超額利潤。本論文亦發現當投資組合為5支股票、資產模型為GJR GARCH(1,1)模型、相關結構型態為多元高斯Copula時可獲得超額利潤。

本文利用隨機控制理論，延續Chang et al. ( 2002 )，採用總和精算成本法，考慮提撥率風險( Haberman and Sung ( 1994 ) )極小的情況下，推導確定給付退休基金之最適提撥與資產配置策略封閉解，資產配置部分考慮股票市場投資組合、永續債券、現金三種部位。 套用公務人員退撫基金第四次精算報告之數據，透過Matlab重覆模擬1,000次，數值結果如下： 1.正常成本與提撥金額呈遞增趨勢，且兩數據差距甚小，符合風險評估函數所設定之提撥率風險極小化的要求。十年控制期間中，正常成本成長5.32倍，從1.03億增加至5.49億；提撥金額成長16.65倍，從0.33億增加至5.56億。275期以前正常成本大於提撥；275之後提撥大於正常成本。 2.初期提撥金額小於給付金額，且投資報酬不足以彌補其差額，因此造成基金規模縮小，但由於提撥金額成長速率大於給付支出，使得基金規模下降程度趨緩，隨後開始穩定成長。十年控制期間中，基金規模從起始的1,000億下降至840億，再上升至約1,314億。 3.股票與債券之持有或放空的部位越多，基金報酬率波動越大，基金規模越大時，可承擔風險的容量增加，因此傾向高風險投資；基金規模越小時，風險承受度變小，所以投資策略反而趨向保守。股票最多持有99.18%、放空90%；債券最多持有293.5%、放空140.14%。 / In this study, we continue using the model of Chang et al. ( 2002 ), which is based on stochastic control theory to study the dynamic funding policy and investment strategy for defined benefit pension plans. The model includes three investable assets: stock market portfolio, consol bond, and cash. We apply “Aggregate Actuarial Cost Method,” so only the contribution rate risk proposed in Haberman and Sung ( 1994 ) is considered when measuring the performance. In addition, we analyzed the data from Taiwan Public Employees Retirement System (Tai-PERS) investigate the optimal contribution and asset allocation through the proposed model and arrived at the following conclusion: 1.The trend of increasing normal cost and contribution as well as the small disparity tally with the requirement of minimum contribution risk as defined in the loss function. 2.In the beginning, the return of investment and contribution are insufficient to cover the benefit payment, causing the fund level to shrink; but as the rate of contribution increases over time and surpasses the benefit payments, the fund level will cease to shrink, and start to grow gradually. 3.There is a positive correlation between the fund level and the risk of investment. In other words, the larger the size of the fund level, the higher the possibility of holding or short selling risky assets.

全球經濟情況變動，壽險公司的資產快速增加，國內投資工具無法滿足壽險公司的投資需求，政府大幅增加了壽險公司的投資範圍，如開放壽險公司海外投資上限，希望能提升壽險公司的資金運用效率。然而金融海嘯過後，壽險公司的投資績效受到打擊，金融資產出現大幅跌價，面臨投資跌價損失、資產減損、投資報酬率下降等情況，投資獲利逐漸下滑，影響了壽險公司的整體營運，經營情況日趨嚴峻。於是近年來，國內壽險公司投資收益佔營收比重逐漸增加，資產配置策略及實務上如何進行資金運用操作，實關係著壽險公司經營穩健度及獲利能力。本論文以一個案人壽公司為例，透過MV模型分析2005年至2011年間，在現行法令限制下，壽險公司投資組合的報酬率與風險之影響為何，且既定風險情況下，分析其投資績效，並探討此壽險公司資產配置是否具效率，又可如何調整配置提升投資報酬率，藉以供作壽險業未來資金運用策略之參考。 / As life insurance company assets rapidly increase and vary with global economical situations, domestic investment means no longer satisfy investing needs of life insurance companies. The Government relaxes investment restrictions, financially and legally, aiming to improve the very investment benefit of life insurance companies. But after the financial tsunami, their investment performance decreased, financial assets declined, unrealized losses on investment and asset impairment occurred, and return on Investment went down. The life insurance company’s overall operating conditions became more and more severe. Thus, the facts that the increasing proportion of domestic life insurance companies’ income on investment, asset allocation policy and practice on how to fund operations, do influence the stability and profitability of life insurance companies. Employing the Markowitz portfolio model, this thesis will analyze the investment benefit of life insurance companies with a specific case of a life insurance company during the period between 2005 and 2011. It reassesses issues below: the relation between capital allocation efficiency and risk of life insurance companies under established risk situations, the efficiency of life insurance companies’ asset allocation, and the rearrangement of asset allocation in order to upgrade capital allocation efficiency. These analyses would provide some reference for life insurance companies’ investing strategies in uses of future funds.

Made available in DSpace on 2010-04-20T21:00:11Z (GMT). No. of bitstreams: 4 Mauricio Mussashi Irie.pdf.jpg: 16022 bytes, checksum: d3dcf1b8020749a12b3baae53334cda5 (MD5) Mauricio Mussashi Irie.pdf.txt: 96735 bytes, checksum: 944036c3b3d1ae823db79daedb65dd6e (MD5) Mauricio Mussashi Irie.pdf: 7355110 bytes, checksum: 880246debd0d864c44768ebd4eaf2e6e (MD5) license.txt: 4886 bytes, checksum: 8fa2d810f5b64e058d76fb4986924cf0 (MD5) Previous issue date: 2009-02-06T00:00:00Z / Este trabalho explora com cuidado o lado específico da implementação de um modelo de alocação de ativos em que o risco é tratado de maneira integrada, não somente através do desvio padrão do portfólio, mas também considerando outras métricas de risco como, por exemplo, o Expected Shortfall. Além disso, utilizamos algumas técnicas de como trabalhar com as variáveis de modo a extrair do mercado os chamados "invariantes de mercado", fenômenos que se repetem e podem ser modelados como variáveis aleatórias independentes e identicamente distribuídas. Utilizamos as distribuições empíricas dos invariantes, juntamente com o método de Cópulas para gerar um conjunto de cenários multivariados simulados de preços. Esses cenários são independentes de distribuição, portanto são não paramétricos. Através dos mesmos, avaliamos a distribuição de retornos simulados de um portfólio através de um índice de satisfação que é baseado em uma função de utilidade quadrática e utiliza o Expected Shortfall como métrica de risco. O índice de satisfação incorpora o trade-off do investidor entre risco e retorno. Finalmente, escolhemos como alocação ótima aquela que maximiza o índice de satisfação ajustado a um parâmetro de aversão ao risco. Perseguindo esses passos, é possível obter um portfólio no qual a alocação em cada ativo, ou classe de ativos, reflete o prêmio esperado ao risco incorrido. / The present work carefully explores the implementation of an asset allocation model in which the risk measure considered is fully integrated, not only through the standard deviation for the portfolio, but also considering other risk metrics, for instance, the Expected Shortfall. Moreover, some statistical tools are used to extract from the market the so called “market invariants”, which are phenomena that tend to repeat themselves and can be modeled as i.i.d. random variables. We use the empirical distribution of the invariants, along with the Method of Copula to generate a set of simulated multivariate price scenarios. These scenarios are independent of distribution, therefore they are non-parametric. With these scenarios we evaluate the simulated return distribution of a portfolio through a satisfaction index which is based on a quadratic utility function and the risk measure considered is the Expected Shortfall. The satisfaction index summarizes the investor trade-off between risk and return. Finally, we choose the optimal allocation that maximizes the satisfaction index adjusted to a risk aversion parameter. In pursuing these steps, it is possible to obtain a portfolio in which the allocation of each asset class or security fully reflects the expected premium to the risk assumed.