Abstract
The explicit results for the classical Merton optimal investment/consumption problem rely on the use of constant risk aversion parameters and exponential discounting. However, many studies have suggested that individual investors can have different risk aversions over time, and they discount future rewards less rapidly than exponentially. While state-dependent risk aversions and non-exponential type (e.g. hyperbolic) discountings align more with the real life behavior and household consumption data, they have tractability issues and make the problem time-inconsistent. We analyze the cases where these problems can be closely approximated by time-consistent ones. By asymptotic approximations, we are able to characterize the equilibrium strategies explicitly in terms of the corrections to solutions for the base problems with constant risk aversion and exponential discounting. We also explore the effects of hyperbolic discounting under proportional transaction costs.
Partially supported by NSF grant DMS-1211906.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Notes
- 1.
These models can be seen as a particular example of the studies on state-dependent utility/preference by Karni [20]. In this case the dependency has an explicit functional form as \(\gamma (\cdot )\).
References
T. Bjork, A. Murgoci, A general theory of markovian time inconsistent stochastic control problems. Preprint (2010)
T. Bjork, A. Murgoci, X. Zhou, Mean-variance portfolio optimization with state-dependent risk aversion. Math. Financ. (2012)
B. Bouchard, L. Moreau, M.H. Soner, Hedging under an expected loss constraint  with small transaction costs. arXiv preprint arXiv:1309.4916 (2013)
J.Y. Campbell, L.M. Viceira, Consumption and portfolio decisions when expected returns are time varying. Q. J. Econ. 114(2), 433–495 (1999)
R. Carmona, Indifference Pricing: Theory and Applications, Series in Financial Engineering (Princeton University Press, Princeton, 2008)
G. Chacko, L.M. Viceira, Dynamic consumption and portfolio choice with stochastic volatility in incomplete markets. Rev. Financ. Stud. 18(4), 1369–1402 (2005)
P. Cheridito, M. Kupper, Composition of time-consistent dynamic monetary risk measures in discrete time. Int. J. Theor. Appl. Financ. 14(01), 137–162 (2011)
M. Chernov, A.R. Gallant, E. Ghysels, G. Tauchen, Alternative models for stock price dynamics. J. Econom. 116(1), 225–257 (2003)
V. Coudert, M. Gex, Does risk aversion drive financial crises? testing the predictive power of empirical indicators. J. Empir. Financ. 15(2), 167–184 (2008)
M.H. Davis, A.R. Norman, Portfolio selection with transaction costs. Math. Oper. Res. 15(4), 676–713 (1990)
I. Ekeland, A. Lazrak, Being serious about non-commitment: subgame perfect equilibrium in continuous time. arXiv preprint arXiv:math/0604264 (2006)
I. Ekeland, A. Lazrak. Equilibrium policies when preferences are time inconsistent. arXiv preprint arXiv:0808.3790 (2008)
I. Ekeland, O. Mbodji, T.A. Pirvu, Time-consistent portfolio management. SIAM J. Financ. Math. 3(1), 1–32 (2012)
J.-P. Fouque, G. Papanicolaou, R. Sircar, K. Solna, Multiscale Stochastic Volatility for Equity, Interest Rate, and Credit Derivatives (Cambridge University Press, Cambridge, 2011)
J.-P. Fouque, R. Sircar, T. Zariphopoulou, Portfolio optimization and stochastic  volatility asymptotics. Preprint (2013)
C. Harris, D. Laibson, Dynamic choices of hyperbolic consumers. Econometrica 69(4), 935–957 (2001)
C.J. Harris, D. Laibson. Hyperbolic discounting and consumption, in Advances in Economics and Econometrics: Theory and Applications, vol. 1, in ed. by M.  Dewatripont, L.P. Hansen, S. Turnovsky (Eighth World Congress, 2002), pp. 258–298
Y. Hu, H. Jin, X.Y. Zhou, Time-inconsistent stochastic linear-quadratic control. SIAM J. Control Optim. 50(3), 1548–1572 (2012)
J. Hull, A. White, The pricing of options on assets with stochastic volatilities. J. Financ. 42(2), 281–300 (1987)
E. Karni, Risk aversion for state-dependent utility functions: measurement and applications. Int. Econ. Rev. 24(3), 637–647 (1983)
T.C. Koopmans, Stationary ordinal utility and impatience. Econom. J. Econom. Soc. 28, 287–309 (1960)
H. Kraft, Optimal portfolios and Heston’s stochastic volatility model: an explicit solution for power utility. Quant. Financ. 5(3), 303–313 (2005)
G. Loewenstein, D. Prelec, Anomalies in intertemporal choice: evidence and an interpretation. Q. J. Econ. 107(2), 573–597 (1992)
R. Merton, Continuous-Time Finance (Wiley, New York, 1992)
H. Pham, Continuous-time Stochastic Control and Optimization with Financial Applications (Springer, Berlin, 2009)
T.A. Pirvu, H. Zhang, Utility indifference pricing: a time consistent approach. Appl. Math. Financ. 20(4), 304–326 (2013)
M. Scheicher, What drives investor risk aversion? daily evidence from the german equity market. BIS Q. Rev. 67–74 (2003)
S. Shreve, H. Soner, Optimal investment and consumption with transaction costs. Ann. Appl. Prob. 4, 609–692 (1994)
R.H. Strotz, Myopia and inconsistency in dynamic utility maximization. Rev. Econ. Stud. 23, 165–180 (1955)
N. Tarashev, K. Tsatsaronis, D. Karampatos, Investors’ attitude towards risk: what can we learn from options? BIS Q. Rev. 6, 57–65 (2003)
J.A. Wachter, Portfolio and consumption decisions under mean-reverting returns: an exact solution for complete markets. J. Financ. Quant. Anal. 37(01), 63–91 (2002)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2014 Springer International Publishing Switzerland
About this paper
Cite this paper
Dong, Y., Sircar, R. (2014). Time-Inconsistent Portfolio Investment Problems. In: Crisan, D., Hambly, B., Zariphopoulou, T. (eds) Stochastic Analysis and Applications 2014. Springer Proceedings in Mathematics & Statistics, vol 100. Springer, Cham. https://doi.org/10.1007/978-3-319-11292-3_9
Download citation
DOI: https://doi.org/10.1007/978-3-319-11292-3_9
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-11291-6
Online ISBN: 978-3-319-11292-3
eBook Packages: Mathematics and StatisticsMathematics and Statistics (R0)