Fake stationary rough Heston volatility: Microstructure-inspired foundations

Fuente: arXiv
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Main Authors: Gnabeyeu, Emmanuel, Pagès, Gilles, Rosenbaum, Mathieu
Format: Preprint
Published: 2026
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_version_ 1866918332995731456
author Gnabeyeu, Emmanuel
Pagès, Gilles
Rosenbaum, Mathieu
author_facet Gnabeyeu, Emmanuel
Pagès, Gilles
Rosenbaum, Mathieu
contents This paper investigates the asymptotic behavior of suitably time-modulated Hawkes processes with heavy-tailed kernels in a nearly unstable regime. We show that, under appropriate scaling, both the intensity processes and the rescaled Hawkes processes converge to a mean-reverting, time-inhomogeneous rough fractional square-root process and its integrated counterpart, respectively. In particular, when the original Hawkes process has a stationary first moment (constant marginal mean), the limiting process takes the form of a time-inhomogeneous rough fractional Cox-Ingersoll-Ross (CIR) equation with a constant mean-reversion parameter and a time-dependent diffusion coefficient. This class of equations is particularly appealing from a practical perspective, especially for the so-called $\textit{fake stationary rough Heston}$ model. We further investigate the properties of such limiting scaled time-inhomogeneous Volterra equations, including moment bounds, path regularity and maximal inequality in the $L^p$ setting for every $p>0$.
format Preprint
id arxiv_https___arxiv_org_abs_2602_11032
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Fake stationary rough Heston volatility: Microstructure-inspired foundations
Gnabeyeu, Emmanuel
Pagès, Gilles
Rosenbaum, Mathieu
Probability
33E12, 45D05, 60G17, 60G22, 60G55, 91G80
This paper investigates the asymptotic behavior of suitably time-modulated Hawkes processes with heavy-tailed kernels in a nearly unstable regime. We show that, under appropriate scaling, both the intensity processes and the rescaled Hawkes processes converge to a mean-reverting, time-inhomogeneous rough fractional square-root process and its integrated counterpart, respectively. In particular, when the original Hawkes process has a stationary first moment (constant marginal mean), the limiting process takes the form of a time-inhomogeneous rough fractional Cox-Ingersoll-Ross (CIR) equation with a constant mean-reversion parameter and a time-dependent diffusion coefficient. This class of equations is particularly appealing from a practical perspective, especially for the so-called $\textit{fake stationary rough Heston}$ model. We further investigate the properties of such limiting scaled time-inhomogeneous Volterra equations, including moment bounds, path regularity and maximal inequality in the $L^p$ setting for every $p>0$.
title Fake stationary rough Heston volatility: Microstructure-inspired foundations
topic Probability
33E12, 45D05, 60G17, 60G22, 60G55, 91G80
url https://arxiv.org/abs/2602.11032