Extreme ATM skew in a local volatility model with discontinuity: joint density approach

Fuente: arXiv
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Main Authors: Gairat, Alexander, Shcherbakov, Vadim
Format: Preprint
Published: 2023
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author Gairat, Alexander
Shcherbakov, Vadim
author_facet Gairat, Alexander
Shcherbakov, Vadim
contents This paper concerns a local volatility model in which volatility takes two possible values, and the specific value depends on whether the underlying price is above or below a given threshold value. The model is known, and a number of results have been obtained for it. In particular, option pricing formulas and a power law behaviour of the implied volatility skew have been established in the case when the threshold is taken at the money. In this paper we derive an alternative representation of option pricing formulas. In addition, we obtain an approximation of option prices by the corresponding Black-Scholes prices. Using this approximation streamlines obtaining the aforementioned behaviour of the skew. Our approach is based on the natural relationship of the model with Skew Brownian motion and consists of the systematic use of the joint distribution of this stochastic process and some of its functionals.
format Preprint
id arxiv_https___arxiv_org_abs_2305_10849
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Extreme ATM skew in a local volatility model with discontinuity: joint density approach
Gairat, Alexander
Shcherbakov, Vadim
Mathematical Finance
Probability
91G20, 60H10, 60J65, 91G80
This paper concerns a local volatility model in which volatility takes two possible values, and the specific value depends on whether the underlying price is above or below a given threshold value. The model is known, and a number of results have been obtained for it. In particular, option pricing formulas and a power law behaviour of the implied volatility skew have been established in the case when the threshold is taken at the money. In this paper we derive an alternative representation of option pricing formulas. In addition, we obtain an approximation of option prices by the corresponding Black-Scholes prices. Using this approximation streamlines obtaining the aforementioned behaviour of the skew. Our approach is based on the natural relationship of the model with Skew Brownian motion and consists of the systematic use of the joint distribution of this stochastic process and some of its functionals.
title Extreme ATM skew in a local volatility model with discontinuity: joint density approach
topic Mathematical Finance
Probability
91G20, 60H10, 60J65, 91G80
url https://arxiv.org/abs/2305.10849