Abstract
We give an explicit PDE characterization for the solution of the problem of maximizing the utility of both terminal wealth and intertemporal consumption under model uncertainty. The underlying market model consists of a risky asset, whose volatility and long-term trend are driven by an external stochastic factor process. The robust utility functional is defined in terms of a HARA utility function with risk aversion parameter 0 < α < 1 and a dynamically consistent coherent risk measure, which allows for model uncertainty in the distributions of both the asset price dynamics and the factor process. Ourmethod combines recent results by Wittmüß (Robust optimization of consumption with random endowment, 2006) on the duality theory of robust optimization of consumption with a stochastic control approach to the dual problem of determining a ‘worst-case martingale measure’.
Similar content being viewed by others
References
Barillas F, Hansen L, Sargent T (2007) Doubts or variability? Working paper, NYU
Burgert C, Rüschendorf L (2005) Optimal consumption strategies under model uncertainty. Stat Decis 23(1):1–14
Castañeda-Leyva N, Hernández-Hernández D (2005) Optimal consumption-investment problems in incomplete markets with stochastic coefficients. SIAM J Control Optim 44(4):1322–1344
Fleming W, Hernández-Hernández D (2003) An optimal consumption model with stochastic volatility. Financ Stoch 7(2):245–262
Fleming W, Soner M (1993) Controlled Markov processes and viscosity solutions. Springer, New York
Föllmer H (1972) The exit measure of a supermartingale. Z Wahrscheinlichkeitstheorie Verw Gebiete 21:154–166
Föllmer H (1973) On the representation of semimartingales. Ann Probab 1:580–589
Föllmer H, Gundel A (2006) Robust projections in the class of martingale measures. Ill J Math 50(2):439–472
Föllmer H, Schied A (2004) Stochastic finance: an introduction in discrete time, vol 27, 2nd edn. de Gruyter Studies in Mathematics, Berlin
Fouque J-P, Papanicolaou G, Sircar KR (2000) Derivatives in financial markets with stochastic volatility. Cambridge University Press, Cambridge
Friedman A (1975) Stochastic differential equations and applications. Academic, New York
Gilboa I, Schmeidler D (1989) Maximin expected utility with non-unique prior. J Math Econ 18:141–153
Gundel A (2005) Robust utility maximization for complete and incomplete market models. Financ Stoch 9(2):151–176
Hernández-Hernández D, Schied A (2006) Robust utility maximization in a stochastic factor model. Stat Decis 24:109–125
Hernández-Hernández D, Schied A (2007) A control approach to robust utility maximization with logarithmic utility and time-consistent penalties. Stoch Proc Appl (in press)
Karatzas I, Žitković G (2003) Optimal consumption from investment and random endowment in incomplete semimartingale markets. Ann Probab 31(4):1821–1858
Korn R, Menkens O (2005) Worst-case scenario portfolio optimization: a new stochastic control approach. Math Methods Oper Res 62(1):123–140
Korn R, Steffensen M. On worst case portfolio optimization. TU Kaiserslautern. Preprint
Korn R, Wilmott P (2002) Optimal portfolios under the threat of a crash. Int J Theor Appl Financ 5(2):171–187
Kramkov D, Schachermayer W (1999) The asymptotic elasticity of utility functions and optimal investment in incomplete markets. Ann Appl Probab 9(3):904–950
Liptser RS, Shiryayev AN (1977) Statistics of random processes I: general theory. Springer, New York
Quenez M-C (2004) Optimal portfolio in a multiple-priors model. Seminar on Stochastic Analysis, Random Fields and Applications IV, 291–321, Progr Probab, 58, Birkhäuser, Basel
Schied A (2005) Optimal investments for robust utility functionals in complete market models. Math Oper Res 30(3):750–764
Schied A (2006) Risk measures and robust optimization problems. Stoch Models 22:753–831
Schied A (2007) Optimal investments for risk- and ambiguity-averse preferences: a duality approach. Financ Stoch 11(1):107–129
Schied A, Wu C-T (2005) Duality theory for optimal investments under model uncertainty. Stat Decis 23(3):199–217
Talay D, Zheng Z (2002) Worst case model risk management. Financ Stoch 6:517–537
Wittmüß W (2006) Robust optimization of consumption with random endowment. TU Berlin. Preprint
Author information
Authors and Affiliations
Corresponding author
Additional information
A. Schied was supported by Deutsche Forschungsgemeinschaft through the SFB 649 “Economic Risk”.
Rights and permissions
About this article
Cite this article
Schied, A. Robust optimal control for a consumption-investment problem. Math Meth Oper Res 67, 1–20 (2008). https://doi.org/10.1007/s00186-007-0172-y
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00186-007-0172-y
Keywords
- Optimal consumption
- Robust control
- Model uncertainty
- Incomplete markets
- Stochastic volatility
- Coherent risk measures
- Convex duality