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16
Small-time asymptotics of option prices and first absolute moments
- Journal of Applied Probability
, 2011
"... We study the leading term in the small-time asymptotics of at-the-money call option prices when the stock price process 푆 follows a general martingale. This is equivalent to studying the first centered absolute moment of 푆. We show that if 푆 has a continuous part, the leading term is of order 푇 in t ..."
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Cited by 14 (2 self)
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We study the leading term in the small-time asymptotics of at-the-money call option prices when the stock price process 푆 follows a general martingale. This is equivalent to studying the first centered absolute moment of 푆. We show that if 푆 has a continuous part, the leading term is of order 푇 in time 푇 and depends only on the initial value of the volatility. Furthermore, the term is linear in 푇 if and only if 푆 is of finite variation. The leading terms for pure-jump processes with infinite variation are between these two cases; we obtain their exact form for stable-like small jumps. To derive these results, we use a natural approximation of 푆 so that calculations are necessary only for the class of Lévy processes.
Small-time expansions of the distributions, densities, and option prices of stochastic volatility models with Lévy Jumps
, 2010
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Small-time expansions for local jump-diffusion models with infinite jump activity
, 2011
"... Abstract. We consider a Markov process X, which is the solution of a stochastic differential equation driven by a Lévy process Z and an independent Wiener process W. Under some regularity conditions, including non-degeneracy of the diffusive and jump components of the process as well as smoothness o ..."
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Cited by 6 (1 self)
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Abstract. We consider a Markov process X, which is the solution of a stochastic differential equation driven by a Lévy process Z and an independent Wiener process W. Under some regularity conditions, including non-degeneracy of the diffusive and jump components of the process as well as smoothness of the Lévy density of Z outside any neighborhood of the origin, we obtain a small-time second-order polynomial expansion for the tail distribution and the transition density of the process X. Our method of proof combines a recent regularizing technique for deriving the analog small-time expansions for a Lévy process with some new tail and density estimates for jump-diffusion processes with small jumps based on the theory of Malliavin calculus, flow of diffeomorphisms for SDEs, and time-reversibility. As an application, the leading term for out-of-the-money option prices in short maturity under a local jump-diffusion model is also derived. 1.
Small-time asymptotics for fast mean-reverting stochastic volatility models
, 2010
"... In this paper, we study stochastic volatility models in regimes where the maturity is small but large compared to the mean-reversion time of the stochastic volatility factor. The problem falls in the class of averaging/homogenization problems for nonlinear HJB type equations where the “fast variable ..."
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Cited by 5 (0 self)
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In this paper, we study stochastic volatility models in regimes where the maturity is small but large compared to the mean-reversion time of the stochastic volatility factor. The problem falls in the class of averaging/homogenization problems for nonlinear HJB type equations where the “fast variable” lives in a non-compact space. We develop a general argument based on viscosity solutions which we apply to the two regimes studied in the paper. We derive a large deviation principle and we deduce asymptotic prices for Out-of-The-Money call and put options, and their corresponding implied volatilities. The results of this paper generalize the ones obtained in [11] (J. Feng, M. Forde and J.-P. Fouque, Short maturity asymptotic for a fast mean reverting Heston stochastic volatility model, SIAM Journal on Financial Mathematics, Vol. 1, 2010) by a moment generating function computation in the particular case of the Heston model.
From Smile Asymptotics to Market Risk Measures
, 2012
"... The left tail of the implied volatility skew, coming from quotes on out-of-the-money put options, can be thought to reflect the market’s assessment of the risk of a huge drop in stock prices. We analyze how this market information can be integrated into the theoretical framework of convex monetary m ..."
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Cited by 4 (0 self)
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The left tail of the implied volatility skew, coming from quotes on out-of-the-money put options, can be thought to reflect the market’s assessment of the risk of a huge drop in stock prices. We analyze how this market information can be integrated into the theoretical framework of convex monetary measures of risk. In particular, we make use of indifference pricing by dynamic convex risk measures, which are given as solutions of backward stochastic differential equations (BSDEs), to establish a link between these two approaches to risk measurement. We derive a characterization of the implied volatility in terms of the solution of a nonlinear PDE and provide a small time-to-maturity expansion and numerical solutions. This procedure allows to choose convex risk measures in a conveniently parametrized class, distorted entropic dynamic risk measures, which we introduce here, such that the asymptotic volatility skew under indifference pricing can be matched with the market skew. We demonstrate this in a calibration exercise to market implied volatility data.
Short-time asymptotics for marginal distributions of semimartingales
, 2012
"... We study the short-time aymptotics of conditional expectations of smooth and non-smooth functions of a (discontinuous) Ito semimartingale; we compute the leading term in the asymptotics in terms of the local characteristics of the semimartingale. We derive in particular the asymptotic behavior of ca ..."
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Cited by 2 (0 self)
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We study the short-time aymptotics of conditional expectations of smooth and non-smooth functions of a (discontinuous) Ito semimartingale; we compute the leading term in the asymptotics in terms of the local characteristics of the semimartingale. We derive in particular the asymptotic behavior of call options with short maturity in a semimartingale model: whereas the behavior of out-of-the-money options is found to be linear in time, the short time asymptotics of at-the-money options is
Efficient Importance Sampling Estimation for Joint Default Probability: the First Passage Time Problem,” Stochastic Analysis with Financial Applications. Editors
- Progress in Probability,
, 2011
"... Abstract This paper aims to estimate joint default probabilities under the structural-form model with a random environment; namely stochastic correlation. By means of a singular perturbation method, we obtain an asymptotic expansion of a two-name joint default probability under a fast mean-revertin ..."
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Cited by 1 (1 self)
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Abstract This paper aims to estimate joint default probabilities under the structural-form model with a random environment; namely stochastic correlation. By means of a singular perturbation method, we obtain an asymptotic expansion of a two-name joint default probability under a fast mean-reverting stochastic correlation model. The leading order term in the expansion is a joint default probability with an effective constant correlation. Then we incorporate an efficient importance sampling method used to solve a first passage time problem. This procedure constitutes a homogenized importance sampling to solve the full problem of estimating the joint default probability with stochastic correlation models.
Small time central limit theorems for semimartingales with applications
, 2012
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Maximum Likelihood Estimation for Small Noise Multiscale Diffusions
, 2013
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