1,113 research outputs found

    Randomisation and recursion methods for mixed-exponential Levy models, with financial applications

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    We develop a new Monte Carlo variance reduction method to estimate the expectation of two commonly encountered path-dependent functionals: first-passage times and occupation times of sets. The method is based on a recursive approximation of the first-passage time probability and expected occupation time of sets of a Levy bridge process that relies in part on a randomisation of the time parameter. We establish this recursion for general Levy processes and derive its explicit form for mixed-exponential jump-diffusions, a dense subclass (in the sense of weak approximation) of Levy processes, which includes Brownian motion with drift, Kou's double-exponential model and hyper-exponential jump-diffusion models. We present a highly accurate numerical realisation and derive error estimates. By way of illustration the method is applied to the valuation of range accruals and barrier options under exponential Levy models and Bates-type stochastic volatility models with exponential jumps. Compared with standard Monte Carlo methods, we find that the method is significantly more efficient

    Explicit solution of an inverse first-passage time problem for L\'{e}vy processes and counterparty credit risk

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    For a given Markov process XX and survival function H\overline{H} on R+\mathbb{R}^+, the inverse first-passage time problem (IFPT) is to find a barrier function b:R+[,+]b:\mathbb{R}^+\to[-\infty,+\infty] such that the survival function of the first-passage time τb=inf{t0:X(t)<b(t)}\tau_b=\inf \{t\ge0:X(t)<b(t)\} is given by H\overline{H}. In this paper, we consider a version of the IFPT problem where the barrier is fixed at zero and the problem is to find an initial distribution μ\mu and a time-change II such that for the time-changed process XIX\circ I the IFPT problem is solved by a constant barrier at the level zero. For any L\'{e}vy process XX satisfying an exponential moment condition, we derive the solution of this problem in terms of λ\lambda-invariant distributions of the process XX killed at the epoch of first entrance into the negative half-axis. We provide an explicit characterization of such distributions, which is a result of independent interest. For a given multi-variate survival function H\overline{H} of generalized frailty type, we construct subsequently an explicit solution to the corresponding IFPT with the barrier level fixed at zero. We apply these results to the valuation of financial contracts that are subject to counterparty credit risk.Comment: Published at http://dx.doi.org/10.1214/14-AAP1051 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Some remarks on first passage of Levy processes, the American put and pasting principles

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    The purpose of this article is to provide, with the help of a fluctuation identity, a generic link between a number of known identities for the first passage time and overshoot above/below a fixed level of a Levy process and the solution of Gerber and Shiu [Astin Bull. 24 (1994) 195-220], Boyarchenko and Levendorskii [Working paper series EERS 98/02 (1998), Unpublished manuscript (1999), SIAM J. Control Optim. 40 (2002) 1663-1696], Chan [Original unpublished manuscript (2000)], Avram, Chan and Usabel [Stochastic Process. Appl. 100 (2002) 75-107], Mordecki [Finance Stoch. 6 (2002) 473-493], Asmussen, Avram and Pistorius [Stochastic Process. Appl. 109 (2004) 79-111] and Chesney and Jeanblanc [Appl. Math. Fin. 11 (2004) 207-225] to the American perpetual put optimal stopping problem. Furthermore, we make folklore precise and give necessary and sufficient conditions for smooth pasting to occur in the considered problem.Comment: Published at http://dx.doi.org/10.1214/105051605000000377 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org
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