Suggested Errata for Cont and Tankov (2004) “Financial Modelling with Jump Processes”

The book by Cont and Tankov (2004) is an excellent introduction to jump processes in finance. The attached document lists some potential typos/inconsistencies in the notation of the 2004 printing that are neither included in the errata published under http://www.cmap.polytechnique.fr/~rama/Jumps/ nor in an updated PDF version of some of the book chapters.

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Stochastic vs. Local Volatility for Barrier Options

As shown in Schoutens et al. (2004), different dynamics for the underlying asset price are able to achieve a similarly good calibration to the market prices of European plain vanilla options. Consequently, these models are able to generate very similar marginal distributions for all future points in time. However, their path-behaviour differs thus often yielding significantly different prices for exotic options. In this post, we provide some intuition for the sign of the price differences between local and stochastic volatility models for barrier and American binary options. These arguments are not novel and we refer to e.g. Baker et al. (2004) for a more in-depth and rigorous discussion.

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Ornstein-Uhlenbeck Stochastic Clocks

After introducing the general idea of stochastic clocks in the previous post, we now consider the case where the instantaneous rate of activity follows a non-Gaussian Ornstein-Uhlenbeck process. The major reference is the paper by Barndorff-Nielsen and Shephard (2001b), see also Barndorff-Nielsen and Shephard (2001a). In this post, we discuss the general stochastic setup that applies to all such models that are driven by an almost surely non-decreasing Lévy processes. For the moment, we leave the particular dynamics of this subordinator unspecified but we will provide examples in future posts.

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Two-Volatility Barrier Options

In the presence of an implied volatility smile, it is not clear which volatility to use when pricing barrier options in the Black-Scholes framework. A simple, although theoretically not justified, tweak is an approach related to outside barrier options. For these contracts, the payoff is determined by one asset while the barrier trigger is linked to another.

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Local Volatility in Terms of Implied Volatility

Jim Gatheral’s book “The Volatility Surface – A Pratitioner’s Guide” (Wiley, 2006) provides an excellent treatment on volatility modelling. Most of the proofs and derivations are only outlined in the book and it is left to the reader to do the intermediate steps. The attached document provides the missing steps in the derivation of the local volatility as a function of the implied volatility on pages 11 – 13 in the book.

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