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APPLICATIONS OF THE
 CE-VALUE FUNCTION PAK
  • Ron Davis
  • Mathematical Programming Services
  • http://www.mathproservices.com/cevalues
  • San Jose State University
  • http://www.cob.sjsu.edu/facstaff/davis_r
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PRESENTATION OUTLINE
  • Background on Exponential Utility
  • Status of the CE-VALUE FUNCTION PAK
  • The CE-VALUE MAXIMAL FRONTIER
  • Application to Portfolio Gamma Model
  • Application to Portfolio Scenario Optimization
  • Application to DPL Decision Analysis
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Exponential Utility
  • U(x) = 1 - exp(-x/T)
  • T = Risk Tolerance
  • What is the maximum wager you would make on a triple-or-nothing bet with even odds?  Multiply that by 2 to get T.
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Certain Equivalent (CE) Value
  • Discrete Distributions


  • Continuous Distributions


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VALUE ADDITIVITY
  • Let G1 and G2 be two independent gambles
  • G1&G2 is the joint receipt of G1 & G2
  • CE(G1&G2) = CE(G1) + CE(G2)
  • Holds for all risk tolerances
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INFORMATION VALUE
Concept Extensions
  • Certain Equivalent Value of Perfect Info
    • CE|PI - Max{CE(Ai)|Prior Info}
  • Certain Equivalent Value of Sample Info
    • CE|SI - Max{CE(Ai)|Prior Info}
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CE-VALUE FUNCTION PAK
  • Add-In for EXCEL
  • DLL for Visual Basic
  • DLL for C++
  • library of value functions
  • computes CE from T and distribution parameters
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CE-Value Functions: Discrete
  • Binomial; Negative Binomial
  • Geometric; HyperGeometric
  • Pascal
  • Poisson
  • Uniform
  • Finite Discrete - {xi,pi}


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CE-Value Functions: Continuous
  • Uniform; Histogram
  • Normal; logNormal
  • Beta; Gamma; Inverse Gamma
  • Exponential; Erlang; Chi-Square
  • Triangular
  • Laplace; Rayleigh; Logistic
  • Weibull



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Example CE-Value Functions
  • Normal


  • Finite Discrete


  • Gamma




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Maximizing the CE-Value
  • Maximize CE(T,distribution parameters)
  • By changing decision variables X
  • Where distribution parameters = g(X)
  • Repeat for range of risk tolerance values
  • Converts stochastic programming problem to a parameterized family of nonlinear programs
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The CE-VALUE MAXIMAL FRONTIER
  • The set of decision variable vectors which optimize the CE value for SOME risk tolerance constitute the CE-Value Maximal Frontier
  • Other solutions are CE-Value dominated and hence sub-optimal
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Concept Extension
  • The mean-variance efficient frontier is the CE-Value Maximal Frontier for the portfolio problem under normal assumptions.
  • The CE-Value Maximal Frontier is the extension to the asymmetric or discrete distribution case
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EXAMPLE APPLICATIONS
  • Portfolio Gamma Model
  • Portfolio model with Scenarios
  • Decision Analysis models in DPL (or Precision Tree?)
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Portfolio Formulation Enhancement
  • Minimize Variance
    • subject to expected return >= r0
  • Maximize CE-Value
    • subject to budget constraint
  • mean-variance efficiency is the same as CE-Value maximality in this case.
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Portfolio Gamma Formulation
  • Maximize CE-Value



  • subject to constraints computing
    • portfolio min
    • portfolio mean
    • portfolio variance


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Backtest Results with
 Portfolio Gamma Model
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Portfolio Optimization with Multiple Scenarios
  • Minimize Variance
    • subject to constraint on expected return
  • Maximize CE-Value of expected returns


    • where ri is the expected return under the ith scenario
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Min Variance Allocations:
Multiple Scenarios
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MAX CE-Value Allocations
Multiple Scenarios
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Performance Comparisons:
Min Var vs. Max CE-Value
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Conclusions
  • Exponential Utility is preferred because it least to Value Additivity
  • CE-Value functions can be developed in
    • closed form, or
    • series expansion
    • numerical integration
  • Parametric optimization wrt Tolerance yields the CE-Value Maximal Frontier
  • CE-Value Maximization is the proper generalization of mean-var efficiency for the asymmetric case.