A stochastic Gordon-Loeb model for optimal cybersecurity investment under clustered attacks

This paper proposes a continuous-time stochastic extension of the Gordon-Loeb model that incorporates Hawkes processes to capture attack clustering, demonstrating through dynamic programming that accounting for such clustering yields more responsive and effective cybersecurity investment policies compared to traditional static or Poisson-based approaches.

Giorgia Callegaro, Claudio Fontana, Caroline Hillairet, Beatrice OngaratoWed, 11 Ma💰 q-fin

Hybrid Hidden Markov Model for Modeling Equity Excess Growth Rate Dynamics: A Discrete-State Approach with Jump-Diffusion

This paper proposes a hybrid Hidden Markov Model that combines Laplace quantile-defined market states with a Poisson-driven jump-duration mechanism to generate synthetic equity excess growth rates that simultaneously preserve heavy-tailed distributions, volatility clustering, and realistic tail-state dwell times, outperforming standard GARCH and HMM models in joint distributional and temporal fidelity.

Abdulrahman Alswaidan, Jeffrey D. VarnerThu, 12 Ma💰 q-fin

A stochastic correlation extension of the Vasicek credit risk model

This paper proposes a tractable stochastic correlation extension of the Vasicek credit risk model using circular diffusion processes to capture time-varying dependence, thereby deriving closed-form expressions for joint default probabilities and demonstrating how correlation risk significantly impacts tail-event assessments through empirical analysis of U.S. bank charge-off rates.

Dhruv Bansal, Mayank Goud, Sourav Majumdar2026-03-06💰 q-fin

Extreme Value Analysis for Finite, Multivariate and Correlated Systems with Finance as an Example

This paper proposes a practical framework for analyzing extreme values in finite, multivariate, and correlated systems—demonstrated through high-frequency finance data—by rotating returns into the correlation matrix's eigenbasis to isolate collective and idiosyncratic effects, thereby enabling the use of univariate peaks-over-threshold methods to estimate tail risks while accounting for nonstationarity.

Benjamin Köhler, Anton J. Heckens, Thomas Guhr2026-03-06🔬 physics