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Random Matrix in Finance Understanding and improving Optimal Portfolios. Instructor: Chris Bemis. Mantao Wang, Ruixin Yang, Yingjie Ma, Yuxiang Zhou, Wei Shao, Zhengwei Liu. Purpose and Phenomenon of Project. The impact of near-zero eigenvalues in mean-variance optimization.
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Random Matrix in Finance Understanding and improving Optimal Portfolios Instructor: Chris Bemis Mantao Wang, Ruixin Yang, Yingjie Ma, Yuxiang Zhou, Wei Shao, Zhengwei Liu
Purpose and Phenomenon of Project The impact of near-zero eigenvalues in mean-variance optimization Finding optimal weights • Covariance matrix • Marchenko-Pustur to fit data • PCA reconstruction
Data 300 stocks 546 weeks Analysis σ, λ, Q Reconstruction Optimize mean variance CONTENTS 1 2 3
1 Data • Bouchard’s idea • Marchenko-Pustur Law
Analysis Eigenvalue Decomposition of Fully Allocated MVO
Data Selection 300 stocks Х 546 weeks Criterion: • Return history over 10 years of weekly data • Biggest market capitalization
Data Filtered Variance-Covariance Matrix
Data Selection 300 stocks Х 546 weeks Why some of eigenvalues close to 0? • Some original return data are extremely small • Random effect • Collinearity among 300 stocks The impact of near-zero eigenvalues in MVO
2 Analysis of Results • Empirical distribution of eigenvalues • Marchenko-Pustur Law • Analysis
Goals: To eliminate the random noise in the covariance matrix Analysis Procedures Correlation Matrix Best Fit M-P Distribution Filter Noisy Data
Analysis Procedures Procedure 1 Correlation Matrix 2 Distribution of Eigenvalues Best Fit M-P Distribution 3 Filter Noisy Data 4
Analysis Ideas Marchenko-Pastur Law Random & Not Random
Analysis Ideas
Analysis Minimization
Analysis Minimization
Fitting result Q = 1.1494
Analysis of largest λ • The largest eigenvalue λ=118.3564
Analysis Total variance explained by noise
3 Reconstruction • Filtered Variance-Covariance Matrix • An Example of Mean-Variance Optimization
Reconstruction Theory
Reconstruction Theory
Analysis Filtered Variance-Covariance Matrix
Reconstruction Calculated Filtered Optimal Weight
Reconstruction Calculated Filtered Optimal Weight
Reconstruction Comparison the weight Weight from Sample • Bigger volatility • Higher concentration • Extreme shorting Weight from filtered Sample • Less volatility • Lower concentration • No extreme shorting
Reconstruction Sample Weight and Filtered Weight Comparison
Reconstruction Sample Weight and Filtered Weight Comparison Expected Return from Sample Covariance Matrix is Expected Return from Sample Covariance Matrix is
Reconstruction Cumulative Value of Filtered Portfolio and Sample Portfolio Per Month
Reconstruction Cumulative Value of Filtered Portfolio and S&P 500 Per Month