Managing Portfolios of Products and Securities S INS MASSACHUSEr OF TECHNOLOGY Martin Quinteros E OCT 14 2008 Submitted to the Sloan School of Management in partial fulfillment of the requirements for the degree of LIBRARIES Master of Science in Operations Research at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY September 2008 @ Massachusetts Institute of Technology 2008. All rights reserved. A Author ................................................ Sloan chool of Management August 14, 2008 Certified by ................ . .. . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gabriel Bitran Professor, Sloan School of Management Thesis Supervisor Accepted by ................. Dimitris Bertsimas Codirector, Operations Research Center ARCHIVES Managing Portfolios of Products and Securities by Martin Quinteros Submitted to the Sloan School of Management on August 14, 2008, in partial fulfillment of the requirements for the degree of Master of Science in Operations Research Abstract In this thesis we study modifications of the classical Mean-Variance Portfolio Optimization model. Our objective is to identify an optimal subset of assets from all available assets to maximize the expected return while incurring the minimum risk. In addition, we test several approaches to measuring the effect of the variance of the portfolio on the optimal asset allocation. We have developed a mixed integer formulation to solve the well known Markowitz portfolio model. Our model captures and solves the certain practical drawbacks that a real investor would face with the Markowitz approach. For example, by selecting a limited number of assets our procedure tends to prevent small allocations of assets. In addition, we find that in most cases, the maximum drawdown increases as a function of the upper bound on the variance of the portfolio and that this result is consistent with intuition, since portfolio risk increases as the chance that a drawdown event occurs also increases. However, we have observed that altering the composition of the portfolio can mitigate the risk of a drawdown event. Thesis Supervisor: Gabriel Bitran Title: Professor, Sloan School of Management Acknowledgments I would like to thank my family, Marta, Domingo, Pablo, Jorge, Ernesto, and my grandmother Porota for their deep love and support throughout my whole life. Although I spent two years far away from you, I was always thinking of you. I would like extend my deepest gratitude to Gabriel Bitran for being much more than an adviser. He is a superb mentor and a close friend. Gabriel was a constant source of support, especially through difficult times at MIT. In addition, Gabriel opened my eyes to new fields beyond Operations Management. Working on my thesis project, I became strongly interested in financial theory and applications and added a new facet to my interests and skills. I would like to acknowledge Arnoldo Hax for his sincere guidance and support throughout my tenure at MIT. Among many things, Arnoldo showed me the value of the management and strategy aspect of business through many conversations and by attending his valuable seminars. It is with his influence that I will now start working in the consulting industry. I would like to acknowledge Andres Weintraub for providing me with the quantitative skills to perform my research, and to instill in me a passion for Operations Research. It is with his support, encouragement, and guidance through good times and bad that I have come to MIT to pursue graduate study. I would like to acknowledge the faculty at the MIT Sloan School of Management, in particular professors Stephen Graves, David Gamarnik and Vivek Farias. I would like to thank Alex Rikun who became my best friend in the United States, and a great roommate. Thanks a lot for your partnership in many situations and our long philosophical conversations at night. I will remember forever our time together and I hope to see you in Chile very soon. I would like to acknowledge Jonathan Kluberg for being a close friend, an excellent roommate, and a partner in many motorcycle trips. It was great working with you through hard problem sets. Upon moving back to Chile, I am sure to find my way to a few more Shabbat dinners. I would like to thank Karen Kotkow for being such a great friend at MIT. You were always there for support and encouragement. In addition, this thesis would be impossible to write without all of your help with the English language. Thanks to the ORC and Sloan OM students for the rich and friendly environment. In particular I would like to thank Thibault, Dan, Garreth, Shioulin, and Tor. It was fun to work next to you and share many situations with you. A special thanks to the golden ORC staff team: Paulette, Laura, and Andrew. You were always willing to help me with any problems I had and speed up any administrative issues. Finally, I would like to thank the Sloan Staff: Michelle Cole, Laura Taranto, Domingo Altarejos, Conor Murphy, and Anna Piccolo. You were always nice, friendly, and helpful. Contents 1 Introduction 1.1 1.2 1.3 Classical Mean-Variance Markowitz Portfolio Optimization Problem (MVO) 1.1.1 Version 1 .................... 1.1.2 Version 2 ........ ....... 1.1.3 Version 3 ........ ... ... . 13 ... . 14 ... . 14 Comments on the Parameters of MVO . . . . . . . . . . . . 14 1.2.1 Arithmetic Rate of Return: fi ......... . . . . 15 1.2.2 Geometric Rate of Return pi . ......... . . . . 15 1.2.3 Covariances and the Power of Diversification . . . . . 15 Contribution of This Thesis . . . . . . . . . . . . . . . . . . 17 ..... ......... 2 The Efficient Frontier and the Stability of Portfolios 19 2.1 1st Database: DB-1 ................ 2.2 Overall Efficient Frontier period 1998-2007 . ........... 19 2.3 Efficient Frontier periods 1998-2000, 2001-2003 and 2004-2007 . 21 2.4 The Rolling Efficient Frontier Period 1998-2007 2.5 Selecting a Target Return ......... 19 . ........ .. ..................... 25 3 Portfolio Optimization Models 3.1 2nd Database: DB-2 ............................... 3.2 Going Beyond the Classical MVO Model ................... 3.3 Selecting an ideal subset of k assets ................... 23 . .... 3.4 Minimum Holding per Asset ............................ 3.5 The 7 M odels .. .. . . . .. .... 3.6 Building Different Scenarios ........................... 3.7 29 .. .. . . .. . .. ... . . . . . .. . .. 29 3.6.1 Model 1 . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. 30 3.6.2 Model 2 ..................... 31 3.6.3 Model 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. 32 3.6.4 Model 4 ..................... ... 33 3.6.5 Model 5 ............................... .. 34 3.6.6 Model 6 ............................... .. 35 3.6.7 Model 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........... ... ........... Analysis of Results for the Different Models .................. . 4 Value of the Portfolio 4.1 4.2 29 Definitions ........... 36 37 39 ......................... . 39 4.1.1 Return of the Optimal Portfolio in Time 7 . .............. 39 4.1.2 Value of Optimal Portfolio in Time t . ................. 39 Tables of V(t) for the 7 Models ......................... 40 4.2.1 Model 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4.2.2 Model 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4.2.3 Model 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4.2.4 Model 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 4.2.5 Model 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.2.6 Model 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.2.7 Model 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 5 Maximum Drawdown Analysis 57 5.1 Definitions ....................................... 5.1.1 Drawdown in Time ............................ 5.1.2 Maximum Drawdown in Time ........... 8 . 57 57 . . . .... . . 57 5.2 Computation of MDDs for the 7 Models 5.2.1 Results and Comments for Models ......... . .................. .. .. . . . . . 58 58 6 Conclusions 61 A Asset Allocation for Model 1 63 B Asset Allocation for Model 2 67 C Asset Allocation for Model 3 71 D Asset Allocation for Model 4 75 E Asset Allocation for Model 5 79 F Asset Allocation for Model 6 83 G Asset Allocation for Model 7 87 Chapter 1 Introduction In the context of Financial Engineering one of the most interesting topics is Portfolio Optimization. The Mean-Variance Portfolio Optimization problem tries to solve the problem of how to optimally allocate wealth among a given set of assets. In simple words, an investor has n assets available to invest in and, knowing their expected returns and risks measured in terms of volatility, he seeks to build the portfolio of assets that will allow him to get the maximum expected return with the minimum risk. With these data, it is interesting to characterize the points that satisfy the previous condition, also known as the Efficient Prontier. The notion of the Efficient Frontier was introduced by Harry Markowitz in 1952 (see [2]), and it basically describes a curve in the return-volatility space such that every point on the curve represents a particular portfolio that achieves a maximum return for a given level of risk or, alternatively, a minimum risk for a given level of return. Clearly a rational investor will select a portfolio on the efficient frontier. However, an important aspect of this optimization problem is that its parameters may change over time. For example, a particular asset can have a annual return of 10% in a particular year and decrease to 5% or 3% in the following year, which implies that stability in the returns is a key factor to consider. Mean-Variance-Efficient Frontier I 2.5 I I I 2 - - C a: g 1.5 0 1 - 0.5 - i 0 1 i 2 i 3 i 4 i 5 i 6 i 7 8 Risk (Standard Deviation) 1.1 Classical Mean-Variance Markowitz Portfolio Optimization Problem (MVO) The theory of Mean-Variance Optimization (MVO) provides a mechanism for the selection of portfolios of securities, or portfolios of assets, in such a way that balances expected returns with risk. Let us consider assets s 1 , S2 ,... ,sn (n > 2) with random returns. Let ri and oi denote the expected return (monthly or annual) and the standard deviation of the return of asset si. For i 4 j, aj denotes the covariance between assets si and sj. Additionally, let r = (ri, r2 , ... , rn)T and E = (oij) represent the expected return and the n x n symmetric covariance matrix with aij = a i , respectively. So, if we define wi to represent the proportion of money invested in security si, one can express the expected return and variance of the resulting portfolio w = (wl,, ... ,wn) as follows: E(rp) = riWi +.-.- + rnw = rTw and Zi Zj uljwiwj = wTw This is also expressed as pij = , which corresponds aiaj ' to the correlations between assets si and sj, therefore Pii = 1. It is important to note that since the variance is always nonnegative, it follows that wtEw > 0 Vw, that is, E is positive semidefinite. One of the constraints that we consider is: n Wi = 1, i=1 which tells us that the investor is investing all his money. We say that a feasible portfolio w is efficient if it has the maximum expected return among all portfolios with the same variance, or, alternatively, if it has the minimum variance among all portfolios that have at least a certain expected return. When we assume that E is positive definite, the variance is a strictly convex function of the portfolio variables and there exists a unique portfolio in the set of admissible portfolios that has the minimum variance. The MVO problem can be formulated in three different but equivalent ways, as we detail in the following sections. 1.1.1 Version 1 The MVO problem can be solved by finding the minimum variance portfolio of the securities 1 to n that achieves at least a target value expected return b: min w2 st. w TECW rT >R Aw = b Cw > d The first constraint indicates that the expected return is no less than the target return value R. Therefore, solving this optimization problem for different values of R in the range Rmin and R,,max yields all the efficient portfolios. The objective function corresponds to half of the total variance of the portfolio, with the constant 1 added for convenience. 1.1.2 Version 2 Another formulation of the MVO problem involves finding the maximum expected return for the portfolio of securities 1 to n that yields at most a given upper bound for the total variance of the portfolio a 2: max rT 2 WTW < a st. Aw = b Cw > d 1.1.3 Version 3 Version 3 is similar to Version 2 but in this case the objective function is a risk-adjusted return function where the constant A serves as a risk aversion constant. ma rTW - AWT w 2 st. Aw = b Cw > d 1.2 Comments on the Parameters of MVO Assuming that we know the historical returns for assets sl, S2,... , sn in the time period t = 1,2,..., T, named ri, there are usually three parameters to be calculated: 1.2.1 Arithmetic Rate of Return: ri The arithmetic rate of return corresponds to the simple average of returns over time. It does not take into account the effect of compounding on the rate of returns. It is computed in the following way: 1 T t t=1 1.2.2 Geometric Rate of Return pi The geometric rate of return is also called the effective rate of return. It takes into consideration the effect of compounding, so it is a more realistic model. The basic equation is the following: T (1+ r) (1+pi)T = t=1 Therefore the effective return can be expressed as 1 =+ Ali 1.2.3 Covariances and the Power of Diversification The covariance between two assets measures how similar the returns of the assets are during a given period of time. The mathematical expression is as follows: T ij = Cov(ri, rj) = ( t=1 As mentioned earlier, the variance of a portfolio in which n assets are allocated according to each weight, w is i=1 j=1 i=1 i=1 j=,j > i Therefore, it is interesting to analyze what determines the size of up. For this purpose, let us consider a naive diversification strategy in which an equally weighted portfolio is for each security. In this case, the previous equation can constructed, that is, setting wi = be rewritten as i=1 j=l,j i=1 i or equivalently, 2 + nn x n(n - 1Oj) n n nxx-1 X n= We notice that there are n variance terms and n(n - 1) covariance terms in the previous equation. If we define the average variance and average covariance of the assets as n Coy- i=1 E n(n- 1) ij i=1 j=1 we can write the variance of the portfolio as 2 12 n n- 1 n From the last equation we can analyze the effect of diversification. When the average covariance among security returns is zero, at it is when all risk is firm-specific, portfolio variance can approach zero. The second term on the right-hand side of the previous equation will be zero in this scenario, while the first term approaches zero as n becomes larger. Hence when security returns are uncorrelated, the power of diversification to reduce portfolio risk is unlimited. (see [4] chapter 7) However, the most important situation is the one in which economy-wide risk factors impart positive correlation among stock returns. In this case, as the portfolio becomes more highly diversified portfolio variance remains positive. Although firm-specific risk, represented by the first term in the equation, is still diversified away, the second term approaches to Cov as n becomes greater. Thus the irreducible risk of a diversified portfolio depends on the covariances of the returns of the component securities, which in turn is a function of the importance of systematic factors in the economy. 1.3 Contribution of This Thesis The main disadvantage of the classical Markowitz Portfolio Optimization Model is that the optimal allocation of individual assets within the portfolio results in positions that can be quite small, thus limiting its practical use. The approach that was employed here allows one to select optimal subsets of assets, each with its corresponding allocation. We analyze different upper bounds for the number of assets in the subset. For example, if there are 50 assets that are available, and a given investor wants to hold only 10 assets in his portfolio our approach allows him to define the 10 assets with their corresponding allocations that would yield the optimal return. Our approach is based solely on quantitative analysis, and therefore, does not take into consideration other aspects of financial theory which may involve behavioral analytic methods, or other considerations. An interesting extension of this work might be to consider these factors as well. Chapter 2 The Efficient Frontier and the Stability of Portfolios 2.1 1st Database: DB-1 The first database that we have used, DB-1, consists of the historical monthly returns of 835 assets from the period January 1998 to December 2007. Hence, these data can be viewed as a 835 by 120 matrix. In order to be able to analyze the data in a more detailed way, we determined the efficient frontier corresponding to the entire time period 1998-2007, and for three distinct intervals from 1998-2000, 2001-2003 and 2004-2007. In addition we determined how the efficient frontier changes over the entire time period (the Rolling Efficient Frontier). 2.2 Overall Efficient Frontier period 1998-2007 With the data in DB-1 we have used MATLAB to compute the covariance matrix and expected returns of the 835 assets during this period of time. These parameters were then used to solve the actual optimization models corresponding to Version 1 of the MVO discussed in Mean-Variance-Efficient Frontier E r- aM w W Risk (Standard Deviation) Figure 2-1: Overall Efficient Frontier 1998-2007 Chapter 1. The specific formulation of the quadratic optimization model was the following: n min, 2 n ZW? + S S i=1 j i=1 Wj ij i Wi = 1 st. i=1 n Swiri = p i=1 i ER From this model we have obtained the overall efficient frontier of optimal portfolios represented in Figure 2-1. It is important to remember that each point (ap, rp) on the curve represents a particular portfolio for which the given target monthly return rp achieves a minimum volatility ap. In the following table we have detailed 20 portfolios on the efficient frontier displaying the monthly returns and the corresponding volatilities of each portfolio. 2.3 Portfolio rp(%) ap(%) 1 0.617 0.028 2 0.788 0.109 3 0.961 0.203 4 1.132 0.297 5 1.303 0.395 6 1.475 0.508 7 1.647 0.629 8 1.818 0.772 9 1.991 0.945 10 2.162 0.145 11 2.333 1.371 12 2.505 1.644 13 2.677 1.951 14 2.848 2.279 15 3.021 2.631 16 3.192 3.011 17 3.364 3.493 18 3.535 4.073 19 3.707 4.716 20 3.878 5.405 Efficient Frontier periods 1998-2000, 2001-2003 and 2004-2007 For these three periods of time, all of which cover 36 months, we have obtained the efficient frontiers represented in Figures 2-2, 2-3 and 2-4: Mean-Variance-Efficient Frontier Risk (Standard Deviation) Figure 2-2: Efficient Frontier 1998-2000 Mean-Variance-Efficient Frontier Risk (Standard Deviation) Figure 2-3: Efficient Frontier 2001-2003 Mean-Variance-Efficient Frontier ra 1.5 g 0 ! ' • · • ·· · 0.5 1 · ·I · 2 2.5 3 1.5 Risk (Standard Deviation) · 3.5 · 4 4.5 Figure 2-4: Efficient Frontier 2004-2007 We see that the efficient frontiers of each period differ significantly from each other. For example, if we want to achieve a portfolio monthly return of 2% we face fairly different volatilities during each period: 0.9% in 1998-2000, 1.6% in 2001-2003 and 3.1% in 2004-2007. Some examples of these differences are illustrated in the following table: Target Return a 1998-2 000 2.4 a2001- 2003 o02004-2007 1% 0.2 0.5 0.8 2% 0.9 1.6 3.1 3% 2.5 3.2 6.1 The Rolling Efficient Frontier Period 1998-2007 Because the efficient frontier shifts over time, a portfolio that was once on the efficient frontier may be not be on the efficient frontier in subsequent time periods. In addition, it is not clear which portfolio on the efficient frontier to select. One solution is to study the time evolution of efficient frontiers and to identify a sequence of portfolios that remain relatively stable from one efficient frontier to the next. By plotting the frontier over time we can attempt to Rolng EffcientFroniers 14 12 10 6 4 ----- · 2 -06 StdDeof RMns Figure 2-5: Rolling Efficient Frontier 1998-2007 identify this region of stability. Figure 2 shows these efficient frontiers plotted as a function of time. We have calculated the efficient frontiers of 40 portfolios during a fixed interval of time that varies by 1 month intervals. To arrive at these data we have used the covariance matrix and expected returns to calculate the efficient frontier, EF-1, corresponding to a defined time period of 50 months from month 1 (Jan 1998) to month 50 (Feb 2002). In the same fashion, analyzing from month 2 (Feb 1998) to month 51 (Mar 2002) we get EF-2, and so on. The efficient frontier corresponding to the final interval, EF-61, is calculated from data corresponding to month 71 (Oct 2003) and month 120 (Dec 2007). 2.5 Selecting a Target Return The efficient frontier changes over time. This is particularly evident from the previous table where we can see the variations in volatility for a given return. One exercise that is interesting to perform is to fix a target monthly return, for example 1.0%, and analyze how the optimal portfolio changes along the 61 efficient frontiers. Analysis of a subset of these data illustrates that the optimal asset allocation changes significantly from one efficient frontier to another, as shown in Figure 2-6. For example, Asset ID 10831 is allocated at 6.95% on EF-27, at 9.52% on EF-28, at 9.93% on EF-29, at 7.88% on EF-30, and then does not appear on the efficient frontiers corresponding to EF-31 onward. Asset ID 2 105 10103 10350 10481 10586 10636 10732 10812 10831 10849 10955 11102 11162 11240 11304 11408 11575 11715 11829 12014 12139 12273 12457 12598 12730 12887 13013 13256 13729 13929 14091 14370 14687 14973 15275 15435 15711 16063 16576 17335 17664 18017 18312 18656 18868 19315 19600 19836 20184 Eff Fro 27 Eff Fro 28 Eff Fro 29 Eff Fro 30 Eff Fro 31 Eff Fro 32 Eff Fro 33 Eff Fro 34 0 0 0 0 0 0 0 0 0.0609 0.064 0.12 0.0999 0.1023 0.0818 0.0508 0.0667 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0091 0 0 0.0657 0.0094 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0788 0.0993 0.0952 0.0695 0 0 0 0 0 0 0 0 0.0503 0.0293 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0161 0.0204 0.0339 0.0041 0 0.0264 0.0505 0.0505 0 0 0 0 0 0 0 0.1525 0 0 0 0 0 0 0.0684 0.0196 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.1423 0.1412 0.1516 0.2163 0.2083 0.167 0.1186 0.1459 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.1698 0.1561 0.1133 0.1308 0.0892 0.0859 0.0812 0.0552 0.3262 0.3745 0.384 0.3089 0.2922 0.3483 0.3085 0.2888 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0104 0 0 0 0 0.057 0.0581 0.0404 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.014 0 0 0 0 0 0 0 0.0604 0.0631 0.0863 0.0732 0.0624 0.0858 0.0799 0.0645 0.1029 0.0934 0.0705 0.1475 0.1669 0.1055 0.0811 0.0775 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Figure 2-6: Rolling Efficient Frontier 1998-2007 Chapter 3 Portfolio Optimization Models 3.1 2nd Database: DB-2 The second database we have used, DB-2, consists of the historical returns of 39 assets over a 51 month period. More precisely, for every asset we have the monthly returns from January 2004 to March 2008. Hence, the data can be viewed as a 39 by 51 matrix. These data have been provided by a portfolio manager who has been making his portfolio allocations on the basis of experience. The next graph (Figure 3.1) describes the correlation matrix for the 39 assets. We have observed that many assets are negatively correlated, which is a desirable feature with respect to the diversification of the portfolio. The red diagonal is equal to 1, since it represents the correlation of an asset with itself. 3.2 Going Beyond the Classical MVO Model In our models we seek to address inefficiencies in the classical MVO model. We address the issue of selecting an ideal subset of assets, and holding a minimum weight of each chosen asset. In addition we determine the effect of introducing several constraints into these models. Figure 3-1: Graph of the correlation matrix for DB-2 3.3 Selecting an ideal subset of k assets A portfolio manager may want to restrict the number of assets allowed in a portfolio. This may be done to lower transaction costs, or for example, when he is attempting to construct a portfolio tracking a benchmark using a limited set of assets. Therefore, selecting a subset of k assets out of the n that are available would involve a complex enumeration strategy of (n) combinations. To simplify this process we need to introduce a integer decision variable xi which will take the value 1 if asset i is included in the subset and 0 otherwise. In terms of the mathematical formulation, we need to add the constraint: n i=1 xi<_k, and link the variable xi with the associated weight wi. 3.4 Minimum Holding per Asset The solution of the classical MVO problem often results in a few large positions and many small positions. In practice, due to transaction costs, small holdings are undesirable. In order to eliminate small holdings threshold constraints of the following form can be used: -i >- Ei I where Ei is the minimum weight accepted for an asset i. 3.5 The 7 Models The 7 models used in this study cover different combinations of the characteristics mentioned above, and were suggested by the portfolio manager. 3.6 Building Different Scenarios For each of the 7 models presented here we have built 13 different scenarios, named S-l, S-2,..,S-13. In each scenario the value of delta (6), which is an upper bound for the monthly standard deviation of the returns of the portfolio, is different. We derive 6 from the annual standard deviation (6 A) of all returns of the portfolio using the following formula: 6A Typically, the value of 6 A is 3.6%, yielding a 6 of 1.039%. Therefore, our calculations for 6 employ values centered around 6 A = 3.6%, spanning the range from 3.2% to 4.4%. In summary, we have solved 7 x 13, or 91, different optimization models. The following sections describe in detail each model with its corresponding mathematical formulation. In addition, at the end of the chapter a summary of the results is presented. A full detail of the results, including the individual asset allocations of each model is presented in the Appendices A, B, C, D, E, F and G. 3.6.1 Model 1 Model 1 corresponds to the original model. An investor is trying to maximize the expected return of the portfolio, subject to an upper bound in the variance. In addition, we have added several constraints to the model. A minimum monthly return of 1.5% for each month is required. The value of k, the number of assets allowed in the portfolio, has been set to 15. We have linked xi to its weight in the portfolio. Finally, no more than 10% of our wealth can be allocated into any given asset. The following model takes these constraints into consideration: n max rp(b) = Z wr i=1 n Zwis= st. n n E EZWi,% •<62 2w Vt Zwiri -1.5% i=i=1 Zxi <k wi < 10% Vi wi 2 -10% Vi x E {0, 1} Vi 3.6.2 Model 2 Model 2 has been derived from Model 1, with the exception that we are not allowing negative weights. In order to illustrate the effects of eliminating some assets from the portfolio we have excluded assets 9, 13, 18, 19, 22 and 32 and determined their effects on the overall return. max rp(6) = iri i=l n st. = 1 i=1 n n +2Z2wiwji < i=1 i=1 j 62 i i=1 n i=1 wi < xi Vi wi < 10% Vi X 9 =0, X 13 = 0, X 18 =0, X 19 = 0, X 22 =0, X 32 wi > 0 Vi xi E {0, 1} Vi 0 3.6.3 Model 3 Model 3 has been derived from Model 2, except that all the weights of the assets are nonnegative. In addition, to determine the effect of a non-negative weight under these conditions we have removed this constraint for asset 47. In other words, asset 47 is the only one that can be shorted. n max rp(6) = Zwiri i=1 n st. w =1 i=1 n n Zw%±ZT + i=1 wiw,%j <62 i=1 j54i n wr >_-1.5% Vt i=1 Zxi <k i=1 wi <xi Vi wi < 10% Vi 9 = 0, 13 = 0, 18 = 0, x 19 = 0, wi > 0 Vi 47 xi E {0,1} Vi 22 = 0, x 32 = 0 3.6.4 Model 4 Model 4 has been derived from Model 3, however, there is no upper bound to the number of assets that can be held in the portfolio. This has been done to determine how the number of assets that are held affects the returns. Additional constraints include setting the upper bound for the weights at 15%, setting the lower bound for the weight of asset 47 at -10%, and in addition to the assets that were excluded in Model 3 we are also excluding asset 50 and 52. n Zwiri max r (6) i=1 n 1i st. i=1 n n j2±•ZZ + i=1 -Wi" j <•62 i=1 j~i wir > -1.5% Vt i=1 wji < xi Vi wi < 15% Vi Z9 0, X13 0, X18 - 0, X19 = 0, 122 = 0, X32 wi > 0 Vi $ 47 w 47 > -0.1 xi E {0, 1} Vi - 0, X50 = 0, X52 = 0 3.6.5 Model 5 Model 5 has been derived from Model 4, but the only difference is that the upper bound for the weights is 10%. n max rp(6) = Zwiri i=1 n st. wi i=1 n n ZW2 U +-o ii wir •2 62 1iaij • > -1.5% Vt i=1 Wi < xi Vi wi < 10% Vi X 9 = 0, X13 = 0, X18 = 0, 119 = 0, 122 = 0, X32 = 0, wi > 0 Vi 7 47 w47 2 -0.1 xi E {0,1} Vi X50 = 0, X52 = 0 3.6.6 Model 6 Model 6 has been derived from Model 5, however, in this model a lower bound for the weights has been set at 1% for all the assets except asset 47, which has no constraints. This constraint has been added so that we avoid holding assets with positions that are less than 1% of the total portfolio weight, since holding allocations of this size is not practical. i=l = i st. i=1 n n L22 i=1 62 2 i=1 jji n wr > -1.5% Vt i=1 wi < xi Vi 0.01 * xi < wi V Vi 47 wi < 10% Vi X9 = 0, X13 = 0, X18 = 0, X19 = 0, X22 = 0, X32 = 0, X50 wi > 0 Vi f47 x E{O,1} Vi = 0, X 52 = 0 3.6.7 Model 7 Model 7 has been derived from Model 6, except that the weight of asset 34 has been set at 23% and the weight for asset for 35 has been set at 10%, for the purposes of understanding how fixed positions of assets affect returns. n max rp()= wiri i=l n st. wi i=1 Z 2 •2 62 i=l i=1 j i=1 i wrt >_ -1.5% Vt wi < Xi Vi 0.01 * i < wi Vi wi• 47 10% Vi = 34 W34 = 23% was = 10% x 9 =- 0, 13 = 0, X 18 = 0, X 1 9 = 0, X2 2 wi 2 0 Vi - 0, 47 xi E {0, 1} Vi X32 0, X 50 = 0, X 52 0 3.7 Analysis of Results for the Different Models As shown in Figure 3-2 the monthly return of the optimal portfolio increases with 6, which is intuitive. In addition, given that our models are designed to maximize the expected returns as an objective function, the return achieved through Model 1 is higher than that of any other model. This is because Model 1 has the least constraints, or equivalently, it has the largest number of feasible solutions. Figure 3-3 shows a summary of the results of the different models. In particular, we can see the monthly return, the number of assets used, and the maximum drawdown (MDD; which will be explained in detail in Chapter 5). It is interesting to see that, even though the number of assets for Models 6 and 7 is not formally constrained by the formulation of the problem (in principle all 31 assets can be selected). Only 17 and 14 assets were selected respectively. From the practical point of view we observed that all the assets are selected when there is no upper bound on the weights. In such instances, some of the assets might appear in the optimal allocation with very small weight. Monthly Return of Optimal Portfolio as a function of Delta 2.500 2.000 Model 1 Model 2 - Model 3 SModel 4 - Model 5 Model 6 -- Model 7 C 1.500 E 1 1.000 0.500 0.000 0.953 0.981 1.010 1.039 1.068 1.097 1.126 1.155 1.184 1.212 1.241 1.270 Delta Figure 3-2: MDD for models 1,2,3,4,5,6 & 7 Annual StD(%) Delta (monthly %) Model 1 Model 2 Model 3 Model 4 Model 6 Model 6 Model 7 %Monthly Return # Assets Used MDD(%) % Monthly Return # Assets Used MDD(%) % Monthly Return # Assets Used MDD(%) % Monthly Return # Assets Used MDD(%) % Monthly Return # Assets Used MDD(%) % Monthly Return # Assets Used MDD(%) % Monthly Return # Assets Used MDD(%) S-1 3.2 0.924 1.737 15 0.58 1.423 15 0.21 1.590 15 1.04 1.595 31 0.25 1.557 31 0.49 1.557 17 0.49 1.386 14 0.44 S-2 3.3 0.953 1.761 15 0.73 1.437 15 0.25 1.613 15 1.1 1.611 31 0.3 1.572 31 0.52 1.572 17 0.53 1.415 15 0.4 S-3 3.4 0.981 1.783 15 0.81 1.451 15 0.29 1.636 15 1.15 1.626 31 0.36 1.586 31 0.56 1.586 17 0.56 1.439 13 0.43 S-4 3.5 1.010 1.803 15 0.88 1.465 15 0.33 1.658 3.6 1.039 1.821 15 0.97 1.479 15 0.35 1.680 15 15 1.2 1.26 1.641 1.656 31 31 0.41 0.47 1.601 1.615 31 31 0.59 0.63 1.601 1.615 16 16 0.6 0.65 1.461 1.482 14 14 0.55 0.48 S-7 3.8 3.7 1.068 1.097 1.842 1.863 15 15 1.15 1.21 1.493 1.507 15 15 0.4 0.45 1.702 1.723 15 15 1.32 1.38 1.671 1.686 31 31 0.53 0.57 1.628 1.642 31 31 0.67 0.71 1.628 1.642 16 16 0.7 0.74 1.501 1.521 14 15 0.63 0.68 S-8 3.9 1.126 1.885 15 0.18 1.521 15 0.51 1.745 15 1.44 1.700 31 0.58 1.655 31 0.74 1.655 16 0.8 1.540 14 0.76 S-9 4.0 1.155 1.908 15 0.4 1.534 15 0.57 1.765 15 1.5 1.713 31 0.63 1.669 31 0.77 1.668 16 0.85 1.556 14 0.86 S-10 S-11 4.1 4.2 1.184 1.212 1.927 1.944 15 15 0.54 0.59 1.548 1.561 15 15 0.59 0.6 1.788 1.807 15 15 1.56 1.62 1.727 1.741 31 31 0.67 0.71 1.682 1.695 31 31 0.81 0.86 1.682 1.695 17 18 0.77 0.81 1.576 1.593 14 10 0., 0.98 S-12 4.3 1.241 1.961 15 0.64 1.574 15 0.62 1.826 15 1.73 1.754 31 0.75 1.708 31 0.9 1.708 16 0.85 1.610 14 1.01 Figure 3-3: Summary of results for models 1,2,3,4,5,6 & 7 S-13 4.4 1.270 1.977 15 0.68 1.587 15 0.67 1.646 15 1.83 1.767 31 0.79 1.721 31 0.95 1.721 16 0.92 1.626 14 1.05 Chapter 4 Value of the Portfolio 4.1 Definitions 4.1.1 Return of the Optimal Portfolio in Time 7 Result of the 91 different optimization models yield values for w, the weight of each asset held in the portfolio. We are interested in understanding how the return varies over time given the optimal allocation of each asset during the respective time period. For a given period of time, r, the return achieved for the optimal portfolio is expressed as Rr(-J) = w ,r Vr = 1,...T i=l 4.1.2 Value of Optimal Portfolio in Time t After computing the return of the optimal portfolio over time we can calculate the value of each respective portfolio over time using the optimized allocations, or w. In other words, an investor who allocates $1 at r = 1 will receive a compounded rate of return during subsequent periods. Therefore, at r = T the value of his portfolio will be t V(t) = I(1 + Rk) Vt = 1,...,T k=1 therefore, using the formula for R", we arrive at the following equation, which takes the effect of compounding into consideration: V(t)= 1-I k=1 1+ EWiri Vt = 1,...,T i=1 For example, in Figure 4-2 corresponding to Model 1, we obtain 13 different values over time for the portfolio under conditions of the 13 different scenarios, as shown by the 13 curves on the graph. The x-axis indicates time, in months, from the period Jan04 to Mar08. The y-axis indicates the value of the optimized portfolio in USD for each scenario. An investor who invests $1 in Mar 04' would have received from $2.430 to $2.778 at the end of the period, depending on the scenario that was employed. 4.2 Tables of V(t) for the 7 Models In an attempt to validate this approach we have compared our results to that of a standard benchmark, the S&P500. The results demonstrate that this approach significantly outperformed the market during these periods. r I V1 V i2 I 1053 v3 v44 .. V7 I v S4 I 1I S-5 I -· "~lr S-7 Snw r i ,z .O I1 i0 I1V 026. I I.lR I 10482 I 8-1 1.UZO 1 i.046 1.056 I 1.062 _ . ..I 1.iU/ 17 9i 1 1.086 1.068 .0.. 1.0I9I . 1.093 1.115 ' 1.133 Vio V11 1.13 1.147 1.176 V 12 I.M1u ' 1.047 1.057 1 .07 1.078 1.097 1.091 1.113 1 048 1 1.096 II 1". 1.133 1.148 1.176 1.211 1.1 . 08 " 0 10.05. I 1078 047 1 1 050 i.U69 1.081 1 .(B1 051 1.000 I 1.100 058 1 601 1 099 | 1.004 1 1.095 1.120 S1.0971 1.122 1.143 1.142 1.156 1.156 1.184 1 1.185 1.215 1 .216 087 . . 1.086 1.110 1.135 1.152 1.181 1.212 1 1.152 1. . . 1.m09 1.085 1.109 1.237 1 239 -I vis V16 I :1 2 V22 V25 V26 1.458 I•1as I 1.609 vI : I -- .. . ·- I .... .. ---. 1.777 If~I~ v37 f- 55oo v 41 . i I..... ... .. ·. ·-:: - :·--- - -.. :--: :'-:: I77 756 177 tnssr V32 1.510 11740 117Z5 I1.748 --.-. I .... - ·--· --.~R , ..--, ··-· ·, ----- ' 1 216 ' 217 1 218 1 1.'•9 ] 1.312 1 1 ---- 1 031 1 1.328 1.466 1.574 11.566 11.580 1_671 1. ---- 1.752 .___ ..... 1.156 1.188 . -.. I-- _ 11 241 1.244 1.245 284 111.242 286 1288 11.318 .290 ] .315 1A1 1.416 E 1.41 1.573 1 1.606 1137 1.137 312 219 ---- 315 1.331 1 335 3 8 1.338 13623 1.3662 .346 11.430 .426 1.362 I; 1.422 --6 .36 1.7 1.331 1.469 I1136 1153 1 1154 1 155 1.184 1185 1.186 · ... 1.335 1.387~ V21 ** CI~ 060 11059 1.61.621070 11.069 068 I 1.090 11.084 1.1.00o8 8883 11.008683 I 08U 11.109 I .... ... I .... 1 108 1.108 1.107 9 =.327 -- *~'·---' =** 1137 1.136 1.152 1.183 1.214 1.264 1 I1.071 v=* 1.Uo 1.0(0 1 .070U .. 1068 1-080 . ... 9 c~· 101050 11+050 1.0 1o028 11028 1,028 1.028 v ,.V8V 1 1.48 049 i I .0•7 r·~ e-o < we a-a 1.U0i2 1806 1 786 8 I . .. . -=1: -1 1.426 1.430 . .. . 1.473 1.478 1. 1.526 1 1528 1532 1 545 1 .590 1 .658 1.552 1.599 1.667 1 .556 1 .604 1 .674 5 1.795 1774 1.5 1 .532 1 51 7 1.776 1.785 1.1 .560 1.609 1.79 .71 .781 .792 1. 1.786 1.7 1. 1.779 1.789 1795 1.81 1.4 1.835 .842 1.8 1.859 1.849 1.870 1854 1 .876 1.893 1.906 1 1.947 1.951 1.935 t 1.422 1.866 1.651 910 1.916 1.956 195 2.079t 2.043 2.017 2.030 29 2.110 2.120 .2.037 2T 2. 2.142 2.151 2.1 2T5 2.7577 9 2 2ES 6857 .0 2.118B I• v4s -T.j34 2• 2 v so .458 2.488 2.515 1 2"541 1 2.586 1 2.613 1 2.643 2.675 2.700 ) A. I-- Value of Portfolio at each time period: Model 1 g Cc C 8 ta C .5 0 0L Ca E 0. 00 203 0"0 Cu 0 10 20 4 30 40 50 Months (1= Jan 04, 51= Mar 08) Figure 4-2: Graph of V(t) for model 1 60 proxy for the market during this period of time. As illustrated in Figure 4-2, under the conditions of every scenario we have tested, Model 1 significantly outperformed the market index. Our results are even more impressive given that the overall market was declining during this period of time. These data provide objective evidence that demonstrates the value of our optimization models, and validates our general strategy of dynamic asset allocation. I C. C:I C) C.) C!(D Cl 4ýLf) M C) G CV) C) - - C? Q C! Go P- CC cm C4 ArC4 C4 C4 c'jcl! 't .... M rý - ClJ 8 C, w Lor cm N IQ Ce cj L-j co C-i 0 L (a~-.6L-k7L 0I 0 L 0 L 0LLL-LLLLLLU cq N N OR -0 '0 cj cm cj W) 0r-a t i8 cliM U) (D 2 OD 2 Cj co(3) rl C', 00 r- CYC\jC\lC\lC14! Lq ýq rl r--: . cq clý C! cliN N ClJ cm v 9 r,,-,, LQ Lq LýAi M IES SN88 't r. LqLQLq M cl cir C2) r7 clCc,,, I Cl v cm C', cr)C-j ccoj C'i C4 Cl) "It 't8 - - - - - - - - -r: to ý: a.(7) WIC')1;7, 12 C.)2 M - Cj C.) r- rý coVCo Ul) 04C4 LO C-)(0 1ý co Fl- CDLo 'r- U. q LO8 cm A C-i V) I "a, I I X a 1 O p. I I a N Lo rCý NCýi Cý I 4 0 4 T V r*-: r*: . . . Ui Id: cv Cl!C\lC4 Ci Ci . MCID ý ý2 ...C4 $(.2 - - - - - - - - ... - C\l LO co0)rl 2 ro-O rý clr- M r- 0) N Lf) rr2 U)Col.C)-It CmLn 2:-P 8 IN LO (D ('D c) cm N cli cliC\l (p .r*ý cq eq C-4 (p ý"ýIn --t -C? cm CjC\l C-i - ------- -ýt ------ Co U) Ln Lc)-W ýo P-Cl) Ul) 't0)CD LO -ce L" Cj Cj C) 8 Rig % , mm co2 co GoIt 50, 2 MUMD cmcm cm q ý! U, M C4 cl cl vi ViCiCiV: "It't 't "it 't -----a --------- - - - - - - , , , I -. ,mr A A A $;rta a C* 1- 10 11 > > >> > > > > > > > > > > > > > > > > >> Value of Portfolio at each time period: Model 2 0 10 20 30 40 Months (1= Jan 04, 51= Mar 08) 50 Figure 4-4: Graph of V(t) for model 2 60 v) co C! (D It CD8 a) to CMV, LOLf)9 to CQ 0 C.) m wm ic) L. fV)V)m V V cm ýC.) ý2L2 04cy CD to c, C> C.)U) w N 0 L9 CiI,Ci .M Cl! CC, ... rý V Luo) v V CY 12" le F4 CY CM Cj 1) ýl 8 V Ci ý; Ci § Ci L V) C, Wý vi a It LO0 rl iz 8 .. . r- CM(D CYIt N r- CC! Iq 10 q PO aqoq . . r- r4 'W'.CM .04.04.CY.CM 04 CIJ CM0ACM C.) 1 C, .1 r 9ý RGo(D C4 CiCi q CYCM is 8 V com 8 V 9! C,CýCi CY. .04.CM 4 02 N ci cj C\i C, C4 Sý3 OR CR CYI C-4 12 CNq C\Yl Cl CD cr) IN Cý C\iC\i CR Ci.Ci cm ICNIJ CQ C\i:! C-J lcj Cý CIJ 91(ýD - - CY Pt V Cý Ci Cý CiC\i cli INUA SA !ý!: C) ...... C-4 M n... (qOR CIJ C4 ICNY CY NNI CMN CMCY 0) cs4VI(0 404282 aqcqoq r*.:cq rý OD Go oj C11ýC4 Cý Lq CýCýCýC4ý - C'i Cý C\iC4C4 C4,CvJCJ CY* 0) . A CM cmM . . .cq cq V w ýo P- (0 r, 0) 1) 00) N CV) V t CM CC',44 ej C\iC\iN Cý N cmci CQC\iN N1 rC.)C) C) CDQ ffý C-2v tgiMýý. P Cli2 (71 9887C\iCýC4Cý CýC-jC\iC\iCýcm -j ODOR 00 a) r*-: co fllý C) 0 aq 0) Zq LOp lz cli 'D 0) Zq LQ U) CD2 m rl U*)(D P, LO Po rCe co r- r- C\Mj -inI (q vCAR r- cj to 't (D - VtV W Clq q Clq. 82 V.V. 83A 0.in.w.ap Iýlq<ýq r- ý2 . .cjIc-4 .cv) .m.. . . .c,.c,) . . ý2 .. cli r- 00 (D I- LO M 0 ý; QtM C)VV cr) C,4V P- CY- 2 LOV 8 awL 4D 'o CM U) C) Cl)R OD0 f2l, Z; .0 9ý 10LC)r- C) V C4Fv Cl 04 cmq) 28 IV F-: r*ýCq Qq 01 C! Cýq ,t ,ý 19 IQU LA Cl Cl Cl C4q 0 C> c"mcNm - - - - - - - - - - C-ý c"M - Lo - - - - - - - - - - - - - - - - Lo - , !ý C. C) C) Ch rc-y m U) !ý2 L2T- v-: is (D !R CY V 'N - - - - - - V cl V[ cl cl 2 4, cl 8 CUM,87 ?1 C4 v v: 7 2C\4 - - -.-: - - - - - - - - - - - -V V U) PP, V C4 LOLo CY lcqi cqi Cql C4C4 -- P46 - - - - - - - - - C4 r; ts U) 1C., --t r, U) V r- (0 m Cl) Cl) LOLC) co U, ý-o . C\j q 10 VýC) 0ý co Ci le ."co aCi Ci V) . . . . . . . cm - -- - - - - - - - - - - - - ý2Z; >ii> > >i> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -----. . . .. Lf)CM V Cl)w m (D C\lV co C') .4WN . . F).MM 7 17 . .-. - .CM4 - - - - C14 C*j m I (D th -q - L V 0 W Value of Portfolio at each time period: Model 3 p4 /1/771 fJ C *10 6) > .= CD S, a) 2 o 1.6 a 1.41 0 a, (D c \\ / Iii / 10 20 30 40 Months (1= Jan 04, 51= Mar 08) Figure 4-6: Graph of V(t) for model 3 8 w I . -1 % CYIW4h-N-4C- 7- -A 7' (D w 7' (0 8 E2W 7A io 0!2 '4ý W 4-1 GO 7' :4 7' m (C -I ý0 8. 8, . . . 71 -W -W -W b. 71 . :P, in . N 7' 7' .04 R :- :' 7' 7. C.) M is 46 7' 00 CD4bý(a -4 0 CDW 7' (0 I =w5' 7^ . . . o .rO . 7. , 7.. -.ý - 7' j 7' CA) . . . . . .I.- N 8 ýg -4 rl) CA 0 N W W -4 7' 7' 7 . Nw K), N, 7' 71. 8 CDC - N) -4 A, 7' . 7A7A7' 7A7A7A7' C42 7' 7A 08,7A 7A -A 4b. w qT.d to -4 -1 . .0, 8 a 7' N MR -4 CWI3 :1. 496 . . . . . . -4 Cw,) 8 -4 106 .16 q C21iil q C- K") ý3 N D?ýD4 7A 7A C2 N-4 (ND INI, 8 8 8 4 Zý 01 Co. 8 C13C13 ODC.)7A -4 .96C.) CA3 L3CGO to !ý ON GI 0 ca CA) 7171. . . 7A. 7 . . . . -. 7' 7' 7' 7A -4 C.)-4 -4 -4 PO8 C> Al w C.) 7A. 7A 71 71 -A rl) (D -4 -4 7' 4h-'4ý, (D CA)0 01.9 T % 7' 7^ 7^ 7A. IDo 9 IS.- 71 -A -1 7ý -4 7' ý d 0 W -4 M M Jb <<<<<< m d C> W d ci -W.01d - - . 71. 71 . . . . . . . . . . -4 W-4 a-4-4 8 W ;9 CWD '2 -4 4ý m . .W ".4h-7. -W R Odd AMMON . . . . . . d -W4 W, ^1 0 . . . 7' 7 . --4 it % w topCA . .. . . W UJW..86-4 7 . N A. -4 71 NO 2,E, < < < < < < < <ý < < < < < < <1<;< 8 ti 9 !4 9 u T a 2ý4: a g =4 g aý t -4 4 OSIMMME8 C, NO 1ý1*0 ME. K) !13 (0 ýD' -4 !IJN 71 -- -1 . . . . . -4 8 " 64ý K) . . . . . 4 C.) A.W ca ca N M !0 !10 4ý 4h, N N !13!10 . WIS= N 7. -. CCOODC*14-4-4 .91 88-498 WS Odd 7 . 7^. . . . :1111, 21H 48W 9 !4 IWM &9 0 4 9 a a *-, a u << << << N. a a :141 NN N N. CA) w ai --4 !2 << CA !2 7' C) 7AC.2 PO 7' a 0 C."C.) -4 CD -4 d CA o . . < Value of Portfolio at each time period: Model 4 0 10 20 30 40 Months (1= Jan 04, 51= Mar 08) 50 Figure 4-8: Graph of V(t) for model 4 49 60 co 71 0 bo 717, OD OD r7ý -4 ýi r,,,, b), C). T ra N jýT j6 14a WCOCa A, I M I r%3 40 71 71. 63 :1 4ý 41- to j _ -11 -4 . . -4. OD0 C) (D 71:1 ::ý:- Z; . . . . . 71.. .1 K) 71 Z. 71 . 71 w Ko,K). cy,W -88.(A-CD (1)0 CTI 0 Co0) CY) C) 0) IJ ()1 0) 0). M COC-nN OD00,OD. 71 71 71:- 71 71 71 71 . . . . 71 71 71 WN K)M. -4 -4 01 CY) co (A CA)Cý CO cn W 4hA. 0 -j I I - - m- N !11-1 N N K"3 K") 4 -4 V .1h.co 4 Cn 411 !2 03 v M w C.) -4t ý4 '8 !Q r3 NN N N N N. rj NN . . .. -d -4 -4 MM -4 OWE .I -4 D?ýR9 10 I d M -4 OD M0..;4 -4 -4 IM0 0 d § 2 0 ro 7' 7' 71-1-1 7- 71 :9 i-ý § § § t 71 71.-1 7- iQ . . . -1 71 71 71 . 8 8."06 99 9 041,12 Cal 71. ... . . . .. . . 4 0 40 Q A. .1 -1 . .1 -1 .1 .1. F, A. .1 0 T 2 71.1 0 ý4 d-d VP-4 N WCo I 'ý4 F.. it Iwý S M 9::4 -1 . . . . .16 .1 7171 CA) .1 w -1 cm 7' 7' w w C.) CA -d 71 . . . . D3 ýjj m (Ynl m.91cn a C CD rý C.) 8 cn w W -4 (D46cn 2 8324 (7)ýg j PS81.11 -4 41-1a co 4h. Lin (W., d.8-M (11 cn mw m E 740) CA 9-4 -4 a FAA,ro 0 T.9 9. w0) -4it D3 10 2 L"In 8 ;:z; i'ý ?c 0)(1) .86A. d-0 * m 7AI.71. 71 (To1 4M C.) .1 .1 71. . . . CF) Mai -4 -4 (a i4 ila ro K;IK) K) P. (OR CAn Ww 811000(-A K) 71 71 9.8ý .06:01w cwaýj C,)K)ýj K) K3. @40 m mew8a -4 S 0 PM K) a W K) C"W A, -j -j -4 717, . . . 71 7- .1 -1 ýA-A. w w -4 to E E E - 4ý -1ýS .06;ý T ;ý 4h, -4 d0d- OWL, -1 . . . . .1 W oo -4-4S CW.) 12 ý4 9-- d- tn 71 71.1 71 71.71. 71. 71 . . . . 71 . . . . 7171 -1 71 717, ý3 N !13N N . K) ha K) N) N31 CA)C.) W 11 " -4 4ý 4ý -A'ýg 0) 8 IJ CII Cyl C" ;5,DI 0 cn w 0 0) CO N) Cn 14 K) In 0 (7) C@M -,j Sj Co -4 - w 8 to 9 (A M ý4 K) C-A 8 co a m 0 -1 a C.) 'g C-0Tý W K) L'I W -4(71 N) co NNNN. r) N 7, -1 %4:.4 WC.) OWD00 'ico TR V ý; -4 CMD -4 (D W 40 -4 A N. kkkkk NN. CAA. 4h 0 q CKII C> Q G) 9 K) 71., q): § -171(P C.) (D C) C"CA wa K) -- CA N (0 71 CA1,13 Value of Portfolio at each time period: Model 5 o .c_ 0C C, CICO .c_ 0) ',0 C C u, c 0) *0 o 0 .E 01 E '5 0) 0 10 20 30 40 Months (1= Jan 04, 51= Mar 08) 50 Figure 4-10: Graph of V(t) for model 5 51 60 rl) -40A A I A it << < MON M I '0') 14 40 NMI 7. LL §P 4 7-L A rjl . , I li1 090 N 7' 7' 71 7' A. W WN 0) cn CYm C.) u 0 7" 7' E i I d7'7' 7' -J -4 48; _ M Ot a 7' 7' 7' 7. ODý414 N -4 CS d. d. 7' d qInr, E E 42 9 E R b-sl C 71:1 -1 . ý R8CA 49 71 680(0 Ico -11881-4Ico 3!. ý d- WON -4 ?4.CA , C.)P. 7' .1 (00 d 7 . . . . . . . 7L , 7' 4b..16 W -4 7' CA1ý 7' d 7L7L 71 N Cýw w li L" " W -4 C'.) C.) iQN ro ýar) 7L 7' 7',d -0ý4ý a d -d 4ý CD w 98.- 7' 7' ca - 8 a 7^ 7' Id 7' 7' rKQ) -i k) t2 CD w (D id 7' 7' 7' 'I 7L 7' 7' C.) 71 -1 Ed-as. 7.7'-,.-. t I(Myl at a 7 C'. 0 -4 7' 71. 7' 0 7' FS L" K) ro co ul C13 C4 7' 7' q) 8 2 8 a6- C> C> 71 7L71 7^ 7L-1 00 9 t a COPO to C>C 4, IM4 NOw 7' 7' 7' 7^ 7' - , 4 - :ý - - OD (m MAN.86 GjulLn 71 N " OD-i FOm 7' 7' " 7' CF)to K) Ln(0 . . . . . . . . . 71 .1 .1 .2 h) 7' 7L 7L . . . . . . . .1 7171. CD w (D -4 Cl) 7L a, 4" 1 to 71 OD 71 -1 -1 . . . . . . . . . . 46C.)C.3 ca w ýs al N ý ii ;-i g ad M ;pb -4 7 7. 7' 7' 7' 7' 7' K)K) (A CA) K)OD . . . . 7' 7' 7' 7' 71 r41 " 6; C.)0 ::4 n Eý':: a) -4 -4 co 0) a ca))(0 N (D(0 << 71. 7' 7' N " k) N MSA82 7' -4 ý4 7' K) K) co 0) CTO (D 7' 7' 7' 7' w C.) 3i 0) 0) 40 ;-t4 . . . . . .. . . . . . . CY) cm -4 71 :-L ;-4 -4 06 4 :-4 7' NO) 7' :1ý ca f%3 !'3N .16a, W w C.)t LIM -4 0 -4. ea t N N N !13!l) !l) !l) !l) N PN al F. !l) !l) N -4 N !1aN13 N NN 47" 7' 7' 7' 7' 7' 7 . w ww K) K) IQ a, T Ab -4 04 -a4l -9. Sý:Pý -4 -4 0 -4 UlCA 0 00 g CY) .0. CY) CY) -4 0 (yj (DI 0 -4 00 (D -J r,3 K) (7)CA C>L" a- 0 M CD-4 -Sý 4ý M 0 Value of Portfolio at each time period: Model 6 0 10 20 30 40 Months (1= Jan 04, 51= Mar 08) 50 Figure 4-12: Graph of V(t) for model 6 60 a 4 RV Cý co Cj~m Fm ', v.: cc C%: Gq - ý O V cl - Arz a 1 U' V IJ 4 SS -.! 2 U I q pC - C-4 9 -~s'. CýC24 M p ! co) rl24!2C rl - rw; 9!;: 2ro- 04 qCiq q It"t t Cý C.) CY vm m Value of Portfolio at each time period: Model 7 1 I IE I lu zu it 40 Ou Months (1= Jan 04, 51= Mar 08) Figure 4-14: Graph of V(t) for model 7 ^ a0 Chapter 5 Maximum Drawdown Analysis 5.1 Definitions One of the most critical concerns of an investor is the possibility of a decrease in the value of an asset he is holding, otherwise called drawdown. As a method of testing the robustness of these optimization models we have considered the effects of drawdown on our returns. 5.1.1 Drawdown in Time The drawdown is the percentage decrease in total returns from the start to the end of a period of time. If the total equity time series is increasing over the time of an entire period, drawdown is 0. Otherwise, it is a negative number, although often the absolute value is considered. DD(t) = V(t) - V(tmin) V(t) 5.1.2 Maximum Drawdown in Time The maximum drawdown is a proxy for downside risk that computes the largest drawdown over all intervals of time that can be determined within a specific interval of time. MDD (%)for Models 1,2,3,4,5,6 & 7 2 1.8 1.6 Model 1 1.4 - 1.2 1 0.8 Model 2 * Model 4 • - Model 5 Model 6 - Model 7 0.6 0.4 0.2 0 0.9238 0.9526 0.9815 1.0104 1.0392 1.0681 1.0970 1.1258 1.1547 1.1836 1.2124 1.2413 1.2702 delta Figure 5-1: MDD for models 1,2,3,6 & 7 MDD = max DD(t) t=1,...,T 5.2 5.2.1 Computation of MDDs for the 7 Models Results and Comments for Models As shown in Figure 5-1 the MDD increases with 6 for almost all the models. However, Model 1 exhibits a significant decline in MDD when we move from scenario 7 to 8. To understand these results we can analyze the composition of assets and the optimal allocations of weights of those assets in scenario 7 and 8 (see Appendix B). The primary difference between these two scenarios is that under scenario 7 asset 44 was not selected, but asset 46 was selected, and under scenario 8 asset 44 was selected and asset 46 was not selected. The difference in monthly returns for these two assets are more than 2-fold; 1.81% for asset 44 and 0.81% for asset 46 (see Appendix B for a table of effective monthly returns for all the assets). As shown in Figure 5-1 Model 2, 3, 4, and 5 all show a consistent upward trend as we move through each respective scenario. Model 6 demonstrates the same phenomena as that of Model 1, albeit on a much smaller scale. In this case, we observe a small decrease moving from scenario 9 to 10. The primary difference between scenario 9 and 10 is that scenario 10 contains all the assets that are in scenario 9, but in addition includes asset 7, which has an effective monthly return of 2.67%, and asset 42, which has an effectively monthly return of 0.99%. It is important to note that this is possible, because in Model 6 we have not constrained the number of assets that can be held in the portfolio. In Model 7 we observe a slight downward trend in MDD, moving from scenario 1 to 2. From scenario 2 to 13 there is a consistent upward trend. The difference between scenario 1 and 2 is that scenario 2 contains all the assets of scenario 1 with the addition of asset 44, which has an effective monthly return of 1.81%. Chapter 6 Conclusions The present results have been compared with that of a financial manager who was selecting assets from the second database on the basis of his experience. it is possible to outperform a sophisticated manager. Our results show that Most of the constraints that have been introduced were that of the portfolio manager, reflecting what he has been trying to accomplish on his own. The results in Chapter 4 illustrate the trade off between variance and return of the portfolio. They also provide some insight into the different types of constraints with regard to this trade-off. The contribution of Chapter 5, the maximum drawdown analysis, illustrates something that is not intuitive, which is the possibility that the maximum drawdown can fall. It is interesting to note that our models have significantly outperformed the S&P500 during this period when the index was used as a benchmark. A next step in this line of research is to perform the portfolio optimization on a prospective basis, since what we have done here is a retrospective, or posterior analysis. Appendix A Asset Allocation for Model 1 0 0 a cca Ira C 0 0 6 026 a ! i i 0 Q C ýa 0 0 0 60 7000QQ70 co Q 0 co -i a aI....O7 o oo OY~oa I i _o 0 0 c-oao a · 0oo oo 9 0 OO 'DI · · ·,·· i 11 m1 ! aK Im 0000 0m !m = ~~~~~~~~ w o: o 00a *oxo a'1, 1a a S6 0 880ao o i III I ·111111·III···I · · · · · · · · ·-- (fu - ccu OC *.. Co 4) (0 0o.D c a .2 4) o o C,00o o C> o; 1c .00 0 i, c; 0 000 OO 00 0 0 o'o 0 C~C ý 6 0 I J 00 aa OO 0 0 0C0000c 00 C, a OO ----- 0 ~ 00-00 ~ OODO 0-0 9 o o 0 0 - IýD Scenario 12 annualSt[ delta Ret_p xi 0 1 0 1 1 0 1 1 0 1 1 0 0 0 0 0 1 1 1 0 0 0 0 1 0 0 0 0 0 0 1 0 1 0 1 0 1 0 0 Scenario 13 4.3 annualStC 1.241 delta 1.961 Retp wi xi 0 0 0.07528 0 0.1 0.1 0 0.1 0.078883 0 0.1 0.1 0 0 0 0 0 0.1 0.1 0.1 0 0 0 0 0.1 0 0 0 0 0 0 0.1 0 0.045837 0 -0.1 0 -0.1 0 0 1 0 1 1 0 1 1 0 1 1 0 0 0 0 0 1 1 1 0 0 0 0 1 0 0 0 0 0 0 1 0 1 0 1 0 1 0 0 4.4 1.270 1.977 wi 0 0.06406 0 0.1 0.1 0 0.1 0.08531 0 0.1 0.1 0 0 0 0 0 0.1 0.1 0.1 0 0 0 0 0.1 0 0 0 0 0 0 0.1 0 0.05063 0 -0.1 0 -0.1 0 0 Figure A-3: Asset Allocation for Model 1 Appendix B Asset Allocation for Model 2 1$1·1·I11 - - -- - - Opooo OO 1PI P 0 flol"Oloaloll-l!I I 01-0 1010-10 0T c> 0-010-0 01-01O 0 DII(LIIIoIwIIIIIIII*,w 0 I C, 00 0- 0 0 0 st 0 TT 22 C 1 P1 · w-1!1 -- - P -. 01P -1-I - ">I -To hLYH1LWLfW··iIIiiiiIW·I --- CI -4 11 c AL m m 0D 00 cp m C(D · K 0 Scenario 5 annualStD delta Retp xl 0 0 1 1 1 1 0 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 0 1 0 0 0 1 0 1 1 0 0 0 1 0 Scenario 6 3.6 annualStD 1.039 delta 1.479 Retp wi xi 0 0 0.058566 0.1 0.1 0.0060356 0 0.067402 0.051791 0.06728 0 0 0 0 0 0 0.1 0 0.1 0 0 0.057157 0 0 0 0 0.014414 0 0 0 0.1 0 0.031323 0.049307 0 0 0 0.096723 0 0 0 1 1 1 1 0 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 0 1 0 0 0 1 0 1 1 0 0 0 1 0 Scenario 7 3.7 annualStD 1.068 delta 1.493 Retp wI xl 0 0 0.044761 0.1 0.1 0.006315 0 0.069785 0.054139 0.07071 0 0 0 0 0 0 0.1 0 0.1 0 0 0.058947 0 0 0 0 0.013199 0 0 0 0.1 0 0.032386 0.049761 0 0 0 0.099997 0 0 0 1 1 1 1 0 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 0 1 0 0 0 1 0 1 1 0 0 0 1 0 Scenario 9 Scenario 8 3.8 annualStD 1.097 delta 1.507 Retp wl xl 0 0 0.031953 0.1 0.1 0.0065449 0 0.072241 0.05635 0.074913 0 0 0 0 0 0 0.1 0 0.1 0 0 0.061304 0 0 0 0 0.012865 0 0 0 0.1 0 0.033354 0.050477 0 0 0 0.1 0 0 0 1 1 1 1 0 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 0 1 0 0 0 1 0 1 1 0 0 0 1 0 3.9 annualStD 1.126 delta 1.521 Ret_p wI xl 0 0 0.01922 0.1 0.1 0.0067725 0 0.074684 0.05855 0.079091 0 0 0 0 0 0 0.1 0 0.1 0 0 0.063647 0 0 0 0 0.012532 0 0 0 0.1 0 0.034314 0.05119 0 0 0 0.1 0 Figure B-2: Asset Allocation for Model 2 69 0 1 0 1 1 1 0 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 0 1 0 0 0 1 0 1 1 0 0 0 1 0 4 1.155 1.534 wi 0 0.0045126 0 0.1 0.1 0.0067383 0 0.07751 0.061284 0.083177 0 0 0 0 0 0 0.1 0 0.1 0 0 0.066314 0 0 0 0 0.013054 0 0 0 0.1 0 0.035286 0.052123 0 0 0 0.1 0 Scenario 10 annualStD delta RetJp xi 0 Scenario 11 4.1 annualStD 1.184 delta 1.548 Retp wI xl 0 0 ScenarIo 12 4.2 annualStD 1.212 delta 1.561 Retp wl xi 0 0 Scenario 13 4.3 annualStD 1.241 delta 1.574 Retp wi xi 0 0 4.4 1.270 1.587 wi 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 0 1 0 0 0 1 0 1 1 0 0 1 1 0 0.1 0.1 0.0075682 0 0.078882 0.062119 0.08807 0 0 0 0 0 0 0.1 0 0.1 0 0 0.06783 0 0 0 0 0.0075155 0 0 0 0.1 0 0.036264 0.051751 0 0 6.685E-10 0.1 0 1 1 1 0 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 0 1 0 0 0 1 0 1 1 0 0 1 1 0 0.1 0.1 0.0087005 0 0.080114 0.061918 0.093764 0 0 0 0 0 0 0.1 0 0.1 0 0 0.067809 0 0 0 0 1.575E-07 0 0 0 0.1 0 0.037386 0.050309 0 0 6.22E-09 0.099999 0 1 1 1 0 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 1 0 0 0 0 1 0 1 1 0 0 1 1 0 0.1 0.1 0.01025 0 0.082681 0.059876 0.1 0 0 0 0 0 0 0.1 0 0.1 0 0 0.066651 0 0 0 4.236E-10 0 0 0 0 0.1 0 0.038849 0.048558 0 0 1.83E-10 0.093135 0 1 1 1 0 1 1 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 0 1 0 0 0 0 1 0 1 1 0 0 1 1 0 0.089625 0.1 0.011669 0 0.08606 0.059425 0.1 0 0 0 0 0 0 0.1 0 0.1 0 0 0.068148 0 0 0 4.247E-09 0 0 0 0 0.1 0 0.041215 0.047137 0 0 1.757E-09 0.096722 0 Figure B-3: Asset Allocation for Model 2 70 Appendix C Asset Allocation for Model 0000 ooooo .. 0- 00000000 00000000 ooooooooo 0-0 .................. 0 0 00 000 C 0 00-5 •0000 oo 00 a 0oo oo I I · I I - o O ................ ___.................... o 00i 0 5o 0 0000 00000 00 0000. O --.- P O OO ... cnooO S1.. +4 , 4 Fo Q p -4 00 so U II 0 0 -, - ,-o - CD 0000 o o 0 000000C O ,,0 00 -0 0. OD 00o - o oo 0 ooo0 0 -1 o 0 0," o-0-- - I I I I 8• o Appendix D Asset Allocation for Model 4 09 0 C, CO m ,I 0) fj c 20 N cnli ga sw8$9 di h t %I-FIT 0 1 L j C t? v ý3 r arp - a -3 pn !iý C]C]" C" m m -4 tglr ----- p 1 : t -- I-I s 9 81 8 $88988 IT -- as - 1 - m . T~i T.,r!Tmmnm TmmZ, 6 I - C - -- - -ic pf I, a C C _ 00 - 0~~r 0 CoC 0 ( 0~ S0ul __" cCa 1- ccu 00 -i -: N r 'oc - C40o LO o; rlr!2 'I.:i ~ 0 00~-- 0 0 0 8 dcj E1-w 060 id 0 co" 0c oU . oL' f': P- LO 6 . 0 v no 0- 0,0 wdi0v0 UJLýJ0ýoULW LýLU 0 v 46 C.)rC' - iu A v C; i ci c.q Ci ic c; c 0 j1Lutu uj0' Q c L 0 : 1= 9 4) c ' ------CI >C-----0 11---- ýC. L L Appendix E Asset Allocation for Model CA: I0 - -- - - - - o C. w -l--I C.) " f- - 2 O PPp !*! cb M-1 -- c m - . .. CC 4w OOQ Cý - . . C- - .. . a CD0 . 0 C>w CýP 10 ca !0G ro -1ý c . . - ný a7, IIII Go rr, 00O 00r C, -- 6 W4 OM Mr~ rP m O-- - 0~ ~ A m "4 M mm0 A -4.- :-6~~~~ O'D m mM r . ODe.o 000 --I - III -I ---I -I . - lp ~ 0 rnrr. l 00 2i 000 0 olp -0 ~ 0 I 0 Co.0 . .j . 3 ~ C,$0 ---0 a 0- 0 0 m0 0 ~ rn1r- C, m~ 00 0. C> p > coCO P P to *161, - -0--m -:4 m~~rn~~rrl~m 0D 0aI - 0~ om 0 4 yl 01C ecn 0 so 00 - - m- -- m - - oCo - -o--o - > ----o -- co - r ,C. .- o-- 0 aopopoo 0o -I- o - m00-"C aa 8 o I• o " co Appendix F Asset Allocation for Model 6 0A (flu (fu u i C! C') 09 CM I, H, -CDI - 1:16C C4s rc- 0 ; f- 008 C 0 :0S.. 4 4!Q0 ; i 0 C; 2i 0 .o C o . 0 ob CP tnn Cr oc C, 11771 6 C 10 f, s __ o ---> C 10 1 . 0 0 -C01 6 c; 00 541~tit a c s 1,1 C> C;ci 00 V- 0 fl ll 0 -* _ 10061 1C, s sQRr-L C4 N IN = U) ct c Zsl 00.0 CNA 0 1 00 C oo C0 0 cl0 C>-00 cm - 0 0 o.0 OF011010 C wo0 ooc0o C 1 .C 0 0100C D ~ 00 o 0 0 e 000 -0 - -1 1 00C >0 C .0 - 0 01. 1 1 1 Appendix G Asset Allocation for Model 7 000 M 0-- 000 0-,0 to 8 0 p. 00 oP00 0000 ,M W -0- 0a c. 0 0 , 0) cp'Di c 6, C> 00W00.000000~ C> 0 -4 -J CA, 00 0 0 I 0 0 l cll> < - 0O0O-10O000r 0 C> 0Y% 00 0 A.P -- -~ po5> PIP P-- to coo so 116pp 1pPIC, 60 . ooo 00 0o 0 - to0 .,•l 0 00 0o 0 0>0' .coooooooo ~ 111 o 00o0 -4J oo 6 Waoolllll:111110 -4:- C 00o0 0 01-PP 01c, oooo. 0 6 0101001 ooo. o 00oo OC o 0 0.O o 00 io H I-19-111il 00 o • .a,.- 00 (U 00 , c -oll-ii-o I aoo oNCM4 7 ooCT CI 7.01' loooro Iooo I III ol011-01 01-011--1001 o 1 oo 111lrl iooOýoooooOGo07oo 1 Ccllr lllT CR - - c - =cc~ ;s In c Vlc H- qfu 4)C 00 cc~ lool Bibliography [1] F. 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