Higher Moment Models for Risk and Portfolio Management
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City Research Online City, University of London Institutional Repository Citation: Ghalanos, Alexios (2012). Higher moment models for risk and portfolio management. (Unpublished Doctoral thesis, City University London) This is the unspecified version of the paper. This version of the publication may differ from the final published version. Permanent repository link: https://openaccess.city.ac.uk/id/eprint/2039/ Link to published version: Copyright: City Research Online aims to make research outputs of City, University of London available to a wider audience. Copyright and Moral Rights remain with the author(s) and/or copyright holders. URLs from City Research Online may be freely distributed and linked to. Reuse: Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. 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City Research Online: http://openaccess.city.ac.uk/ [email protected] CITY UNIVERSITY Higher Moment Models for Risk and Portfolio Management by Alexios Ghalanos A thesis submitted in partial fulfillment for the degree of Doctor of Philosophy in the Faculty of Finance Cass Business School December 2012 Contents List of Figures iv List of Tables v Acknowledgements vii Thesis Deposit Agreement ix Abstract xi Introduction 3 1 GARCH Dynamics and Time Varying Higher Moments 4 1.1 The Autoregressive Conditional Density Model .............. 6 1.2 Empirical Studies ............................... 9 1.3 Dataset Choice and Motivation ....................... 11 1.4 The ACD-GH Model ............................. 13 1.5 Estimation .................................. 18 1.5.1 Simulated Parameter Consistency ................. 20 1.5.2 Inference and Goodness of Fit .................... 22 1.5.3 Optimization Strategy ........................ 26 1.5.4 ACD Forecasting and Simulation .................. 26 1.5.5 Higher Moment News Impact Curves ................ 27 1.5.6 Competing Distributions ....................... 28 1.6 The Cost of GARCH ............................. 38 1.6.1 The BDS test of i.i.d. ........................ 38 1.6.2 GMM Orthogonality Test ...................... 41 1.6.3 Non-Parametric Transition Density Test .............. 41 1.6.4 Value at Risk and Tail Events .................... 43 1.7 Conclusion .................................. 45 2 Multivariate GARCH Dynamics and Dependence 46 2.1 Multivariate GARCH ............................ 48 2.1.1 Direct Multivariate Extension Models ............... 49 i Contents ii 2.1.2 Conditional Correlation Models ................... 52 2.2 MGARCH with Flexible Margins: The DCC Copula model ....... 59 2.2.1 Copulas ................................ 60 2.2.2 Correlation and Kendall’s τ ..................... 61 2.2.3 Transformations and Consistency .................. 62 2.2.4 The DCC Student Copula ...................... 63 2.3 Multivariate Distributions and Normal-Mean Variance Mixtures ..... 65 2.3.1 The Multivariate Laplace Model and its Extensions ....... 69 2.4 Empirical Application ............................ 74 2.5 Conclusion .................................. 82 3 Multivariate ACD Dynamics and Independence 84 3.1 The Independent Factor Model ....................... 85 3.1.1 Conditional factor dynamics ..................... 88 3.2 Conditional Co-Moments .......................... 90 3.3 The Portfolio Conditional Density ..................... 92 3.4 Estimation .................................. 94 3.5 Empirical application ............................. 97 3.5.1 Model Estimation and In-Sample Fit ................ 97 3.5.2 Co-Moment News Impact Surface .................. 101 3.5.3 Model Risk Forecast Comparison .................. 105 3.5.4 Model Optimal Portfolio Forecast Comparison .......... 107 3.5.4.1 Taylor Series Utility Expansion and Higher Moments . 108 3.5.4.2 Extreme Loss Aversion via MiniMax Optimization . 113 3.6 Conclusion .................................. 116 4 Active Weights for Bad Benchmarks 118 4.1 Stochastic Programming Models ...................... 121 4.2 Risk and Deviation: Models and Properties ................ 125 4.2.1 Mean Variance (EV ) ......................... 129 4.2.2 Mean Absolute Deviation (MAD) .................. 130 4.2.3 MiniMax ............................... 132 4.2.4 Lower Partial Moments ....................... 132 4.2.5 Conditional Value at Risk and Spectral Measures ......... 136 4.3 Applied Optimization ............................ 138 4.3.1 Fractional Programming and Optimal Risk-Reward Portfolios . 139 4.3.2 Smooth Approximations to Discontinuous Functions ....... 140 4.4 Empirical Application ............................ 142 4.4.1 Data Description and Characteristics ................ 144 4.4.1.1 ARCH Effects ....................... 148 4.4.1.2 Multivariate Normality .................. 148 4.4.1.3 Constant Correlation ................... 150 4.4.2 Data Generating Models ....................... 150 4.4.3 Risk Models .............................. 151 4.4.4 Transaction Costs and Long-Short Margin Accounting . 152 4.4.5 Results ................................ 153 Contents iii 4.5 Conclusion .................................. 168 Conclusion 173 A The Generalized Hyperbolic Distribution 174 A.1 The Standardized GH Density ........................ 174 A.2 The GH characteristic function ....................... 176 B The Student and Skewed Student Distributions 178 B.1 The Standardized Student Density ..................... 178 B.2 The Standardized Skewed Student Density ................. 179 C Goodness of Fit and Operational Risk Tests 181 C.1 Parametric and Non Parametric Density Tests .............. 181 C.2 Value at Risk Tests .............................. 183 C.3 The Model Confidence Set .......................... 186 D Nonlinear Fractional Programming Portfolios 188 D.1 General Constraints and Derivatives .................... 188 D.1.1 Linear Reward Fractional Constraint ................ 188 D.1.2 Leverage Constraint ......................... 189 D.1.3 Linear Bounds and Inequalities ................... 189 D.2 Objective Functions and Derivatives .................... 189 D.2.1 Fractional Mean-Variance Objective ................ 190 D.2.2 Fractional Mean-Minimax ...................... 190 D.2.3 Fractional Mean-MAD ........................ 190 D.2.4 Fractional Mean-LPM ........................ 191 D.2.5 Fractional Mean-CVaR ....................... 191 E Supplemental Tables 192 E.1 Pairwise P-values of Portfolio SR Differences ............... 192 F Software 196 F.1 Univariate GARCH and ACD Models ................... 196 F.2 Multivariate GARCH and ACD models .................. 196 F.3 Portfolio Optimization ............................ 197 Bibliography 198 List of Figures 1.1 GH Skewness and Excess Kurtosis Contour Plots ............. 19 1.2 Higher Moment News Impact Curves .................... 29 1.3 Skewness and Kurtosis Surfaces ....................... 30 3.1 Factor Loadings ................................ 102 3.2 Factor Loadings ................................ 103 3.3 Covariance News Impact Surface ...................... 104 3.4 CoSkewness News Impact Surface ...................... 105 3.5 CARA Based Portfolio (λ = 25) and Differential Weight Allocation . 112 4.1 Upper to Lower Partial Moment Utility .................. 135 4.2 Actual vs Calculated DJIA ......................... 147 4.3 Selected Portfolios vs Benchmarks ..................... 161 iv List of Tables 1.1 Summary statistics for 14 MSCI World iShares .............. 12 1.2 Simulated parameter density and RMSE of ACD higher moment dynamics 21 1.3 ACD parameter estimates for 14 MSCI World iShares .......... 25 1.4 Out-of-sample VaR and density forecast tests for 14 MSCI World iShares (NIG, HYP and GH) ............................. 33 1.5 Out-of-sample VaR and density forecast tests for 14 MSCI World iShares (SSTD and JSU) ............................... 34 1.6 VaR model comparison on 14 MSCI World iShares ............ 37 1.7 GARCH BDS test under alternative dynamics ............... 40 1.8 GARCH orthogonality tests under alternative dynamics ......... 42 1.9 GARCH Hong-Li tests under alternative dynamics ............ 43 1.10 GARCH Berkowitz density tests under alternative dynamics ....... 44 2.1 AGDCC comparative estimates (global equity and bond indices) . 56 2.2 Diagonal BEKK Model under 4 conditional distributions (14 MSCI iShares) 75 2.3 Diagonal AGDCC model under 2 conditional distributions (14 MSCI iShares) .................................... 76 2.4 MGARCH models: GMM misspecification test (14 MSCI iShares) . 78 2.5 MGARCH models: Hong-Li misspecification test (14 MSCI iShares) . 79 2.6 Scalar BEKK vs DCC: cost of misspecification .............. 80 3.1 IFACD vs CHICAGO: Parameter estimates and in-sample fit (14 MSCI iShares) .................................... 99 3.2 Independence vs Dependence: Hong-Li misspecification test (14 MSCI iShares) .................................... 101 3.3 IFACD vs CHICAGO: Forecast density and tail tests ........... 107 3.4 Time varying higher co-moments portfolio with CARA utility . 111 3.5 IFACD, CHICAGO and DCC based portfolios under MiniMax criterion 115 4.1 LP vs smooth approximations to NLP: (CVaR and LPM) ........ 142 4.2 LP vs smooth approximations to NLP: (MAD and Minimax) . 143 4.3 Dow Jones Industrial constituent changes since 1959 ........... 146 4.4 Dow Jones Industrial constituents ARCH effects ............