Hostname: page-component-5c6d5d7d68-xq9c7 Total loading time: 0 Render date: 2024-08-08T17:39:50.649Z Has data issue: false hasContentIssue false

Optimal stopping for the exponential of a Brownian bridge

Published online by Cambridge University Press:  04 May 2020

Tiziano de Angelis*
Affiliation:
University of Leeds
Alessandro Milazzo*
Affiliation:
Imperial College London
*
*Postal address: School of Mathematics, University of Leeds, Woodhouse Lane, LS2 9JTLeeds, UK. Email address: t.deangelis@leeds.ac.uk
**Postal address: Department of Mathematics, Imperial College London, 16-18 Princess Gardens, SW7 1NELondon, UK. Email address: a.milazzo16@imperial.ac.uk

Abstract

We study the problem of stopping a Brownian bridge X in order to maximise the expected value of an exponential gain function. The problem was posed by Ernst and Shepp (2015), and was motivated by bond selling with non-negative prices.

Due to the non-linear structure of the exponential gain, we cannot rely on methods used in the literature to find closed-form solutions to other problems involving the Brownian bridge. Instead, we must deal directly with a stopping problem for a time-inhomogeneous diffusion. We develop techniques based on pathwise properties of the Brownian bridge and martingale methods of optimal stopping theory, which allow us to find the optimal stopping rule and to show the regularity of the value function.

Type
Research Papers
Copyright
© Applied Probability Trust 2020

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Avellaneda, M. and Lipkin, M.D. (2003). A market-induced mechanism for stock pinning. Quant. Finance 3, 417425.10.1088/1469-7688/3/6/301CrossRefGoogle Scholar
Baurdoux, E. J., Chen, N., Surya, B. A. and Yamazaki, K. (2015). Optimal double stopping of a Brownian bridge. Adv. Appl. Prob. 47, 12121234.10.1017/S0001867800049089CrossRefGoogle Scholar
Boyce, W. M. (1970). Stopping rules for selling bonds. Bell J. Econ. Manag. Sci. 1, 2753.10.2307/3003021CrossRefGoogle Scholar
De Angelis, T. (2015). A note on the continuity of free-boundaries in finite-horizon optimal stopping problems for one-dimensional diffusions. SIAM J. Control Optimization 53, 167184.10.1137/130920472CrossRefGoogle Scholar
De Angelis, T. and Ekström, E. (2017). The dividend problem with a finite horizon. Ann. Appl. Prob. 27, 35253546.10.1214/17-AAP1286CrossRefGoogle Scholar
De Angelis, T. and Kitapbayev, Y. (2017). Integral equations for Rost’s reversed barriers: existence and uniqueness results. Stoch. Process. Appl. 127, 34473464.10.1016/j.spa.2017.01.009CrossRefGoogle Scholar
De Angelis, T. and Peskir, G. (2019). Global $\textrm{C}^1$ regularity of the value function in optimal stopping problems. To appear in Ann. Appl. Probab. (arXiv:1812.04564).Google Scholar
Detemple, J., Kitapbayev, Y. and Zhang, L. (2018). American option pricing under stochastic volatility models via Picard iterations. Working paper.Google Scholar
Dvoretzky, A. (1967). Existence and properties of certain optimal stopping rules. In Proc. Fifth Berkeley Symp. Math. Statist. Prob., Vol. 1, University of California Press, Berkeley, pp. 441452.Google Scholar
Ekström, E. and Vaicenavicius, J. (2020). Optimal stopping of a Brownian bridge with an unknown pinning point. Stoch. Process. Appl. 130, 806823.10.1016/j.spa.2019.03.018CrossRefGoogle Scholar
Ekström, E. and Wanntorp, H. (2009). Optimal stopping of a Brownian bridge. J. Appl. Prob. 46, 170180.10.1239/jap/1238592123CrossRefGoogle Scholar
Ernst, P. and Shepp, L. (2015). Revisiting a theorem of LA Shepp on optimal stopping. Commun. Stoch. Anal. 9, 419423.Google Scholar
Föllmer, H. (1972). Optimally stopping a Brownian bridge with an unknown pinning time: a Bayesian approach. J. Appl. Prob. 3, 557571.10.2307/3212325CrossRefGoogle Scholar
Gilbarg, D. and Trudinger, N. S. (2001). Elliptic Partial Differential Equations of Second Order. Springer, Berlin.Google Scholar
Glover, K. (2019 ). Optimal stopping of a Brownian bridge with an uncertain pinning time. .10.1016/j.spa.2020.03.007CrossRefGoogle Scholar
Jaillet, P., Lamberton, D. and Lapeyre, B. (1990). Variational inequalities and the pricing of American options. Acta Appl. Math. 21, 263289.10.1007/BF00047211CrossRefGoogle Scholar
Jeannin, M., Iori, G. and Samuel, D. (2008). Modeling stock pinning. Quant. Finance 8, 823831.10.1080/14697680701881763CrossRefGoogle Scholar
Karatzas, I. and Shreve, S. E. (1998). Methods of Mathematical Finance. Springer, New York.Google Scholar
Kim, I. J. (1990). The analytic valuation of American options. Rev. Financial Studies 3, 547572.10.1093/rfs/3.4.547CrossRefGoogle Scholar
Leung, T., Li, J. and Li, X. (2018). Optimal timing to trade along a randomized Brownian bridge. Internat. J. Financial Studies 6, 75.10.3390/ijfs6030075CrossRefGoogle Scholar
Pedersen, J. L. and Peskir, G. (2000). Solving non-linear optimal stopping problems by the method of time-change. Stoch. Anal. Appl. 18, 811835.10.1080/07362990008809698CrossRefGoogle Scholar
Peskir, G. (2005). On the American option problem. Math. Finance 15, 169181.10.1111/j.0960-1627.2005.00214.xCrossRefGoogle Scholar
Peskir, G. and Shiryaev, A. (2006). Optimal Stopping and Free-Boundary Problems. Birkhäuser, Basel.Google Scholar
Shepp, L. A. (1969). Explicit solutions to some problems of optimal stopping. Ann. Math. Statist. 40, 993.10.1214/aoms/1177697604CrossRefGoogle Scholar