Lévy processes as weak limits of rough Heston models

Fuente: arXiv
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Autori principali: Bondi, Alessandro, Forde, Martin
Natura: Preprint
Pubblicazione: 2025
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author Bondi, Alessandro
Forde, Martin
author_facet Bondi, Alessandro
Forde, Martin
contents We show weak convergence of the time-$t$ marginals for the integrated variance in a re-scaled rough Heston model to an Inverse Gaussian Lévy process. This shows we can obtain such a limit without having to impose that the true Hurst exponent $H$ for the model is $\frac{1}{2}$ as in [Abi Jaber, & De Carvalho, 2024], or that $H\searrow -\frac{1}{2}$ as in [Abi Jaber, Attal, & Rosenbaum, 2025], so the result potentially has increased financial relevance. We later extend the analysis to the case where $V$ has jumps, showing weak convergence of the finite-dimensional distributions of the integrated variance to a deterministic time-change of the first-passage time process to lower barriers for a more general class of spectrally positive Lévy processes. This convergence result is then strengthened to a functional setting, namely on the space of càdlàg functions on the non-negative half-line endowed with the $M_1$ topology.
format Preprint
id arxiv_https___arxiv_org_abs_2508_14835
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Lévy processes as weak limits of rough Heston models
Bondi, Alessandro
Forde, Martin
Probability
60H20, 45D05, 60F05, 60G22
We show weak convergence of the time-$t$ marginals for the integrated variance in a re-scaled rough Heston model to an Inverse Gaussian Lévy process. This shows we can obtain such a limit without having to impose that the true Hurst exponent $H$ for the model is $\frac{1}{2}$ as in [Abi Jaber, & De Carvalho, 2024], or that $H\searrow -\frac{1}{2}$ as in [Abi Jaber, Attal, & Rosenbaum, 2025], so the result potentially has increased financial relevance. We later extend the analysis to the case where $V$ has jumps, showing weak convergence of the finite-dimensional distributions of the integrated variance to a deterministic time-change of the first-passage time process to lower barriers for a more general class of spectrally positive Lévy processes. This convergence result is then strengthened to a functional setting, namely on the space of càdlàg functions on the non-negative half-line endowed with the $M_1$ topology.
title Lévy processes as weak limits of rough Heston models
topic Probability
60H20, 45D05, 60F05, 60G22
url https://arxiv.org/abs/2508.14835