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Long memory score-driven models as approximations for rough Ornstein-Uhlenbeck processes

Published: September 11, 2025 | arXiv ID: 2509.09105v2

By: Yinhao Wu, Ping He

Potential Business Impact:

Makes computer models of stock prices better.

Business Areas:
Simulation Software

This paper investigates the continuous-time limit of score-driven models with long memory. By extending score-driven models to incorporate infinite-lag structures with coefficients exhibiting heavy-tailed decay, we establish their weak convergence, under appropriate scaling, to fractional Ornstein-Uhlenbeck processes with Hurst parameter $H < 1/2$. When score-driven models are used to characterize the dynamics of volatility, they serve as discrete-time approximations for rough volatility. We present several examples, including EGARCH($\infty$) whose limits give rise to a new class of rough volatility models. Building on this framework, we carry out numerical simulations and option pricing analyses, offering new tools for rough volatility modeling and simulation.

Country of Origin
🇨🇳 China

Page Count
42 pages

Category
Mathematics:
Probability