On the short-time behaviour of up-and-in barrier options using Malliavin calculus
Òscar Burés
TL;DR
This work analyzes the short-maturity behavior of up-and-in barrier options under general stochastic volatility using Malliavin calculus. By studying the law of the supremum of the log-price, the authors derive a concentration bound and a density estimate for the maximum, leading to an upper bound on barrier option prices that decays faster than any polynomial as the maturity $T$ tends to zero. The framework is applied to the Rough Bergomi model, with a truncation argument ensuring validity under unbounded volatility, and numerical experiments corroborate the theoretical findings that barrier options decay more rapidly than European calls at short maturities. These results provide rigorous insights into zero-maturity pricing of path-dependent options in rough-volatility settings, informing both pricing and risk management in practice.
Abstract
In this paper we study the short-maturity asymptotics of up-and-in barrier options under a broad class of stochastic volatility models. Our approach uses Malliavin calculus techniques, typically used for linear stochastic partial differential equations, to analyse the law of the supremum of the log-price process. We derive a concentration inequality and explicit bounds on the density of the supremum in terms of the time to maturity. These results yield an upper bound on the asymptotic decay rate of up-and-in barrier option prices as maturity vanishes. We further demonstrate the applicability of our framework to the rough Bergomi model and validate the theoretical results with numerical experiments.
