Modeling discrete common-shock risks through matrix distributions

Fuente: arXiv
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Main Authors: Bladt, Martin, Cheung, Eric C. K., Peralta, Oscar, Woo, Jae-Kyung
Format: Preprint
Published: 2025
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author Bladt, Martin
Cheung, Eric C. K.
Peralta, Oscar
Woo, Jae-Kyung
author_facet Bladt, Martin
Cheung, Eric C. K.
Peralta, Oscar
Woo, Jae-Kyung
contents We introduce a novel class of bivariate common-shock discrete phase-type (CDPH) distributions to describe dependencies in loss modeling, with an emphasis on those induced by common shocks. By constructing two jointly evolving terminating Markov chains that share a common evolution up to a random time corresponding to the common shock component, and then proceed independently, we capture the essential features of risk events influenced by shared and individual-specific factors. We derive explicit expressions for the joint distribution of the termination times and prove various class and distributional properties, facilitating tractable analysis of the risks. Extending this framework, we model random sums where aggregate claims are sums of continuous phase-type random variables with counts determined by these termination times, and show that their joint distribution belongs to the multivariate phase-type or matrix-exponential class. We develop estimation procedures for the CDPH distributions using the expectation-maximization algorithm and demonstrate the applicability of our models through simulation studies and an application to bivariate insurance claim frequency data.
format Preprint
id arxiv_https___arxiv_org_abs_2502_21172
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Modeling discrete common-shock risks through matrix distributions
Bladt, Martin
Cheung, Eric C. K.
Peralta, Oscar
Woo, Jae-Kyung
Statistics Theory
We introduce a novel class of bivariate common-shock discrete phase-type (CDPH) distributions to describe dependencies in loss modeling, with an emphasis on those induced by common shocks. By constructing two jointly evolving terminating Markov chains that share a common evolution up to a random time corresponding to the common shock component, and then proceed independently, we capture the essential features of risk events influenced by shared and individual-specific factors. We derive explicit expressions for the joint distribution of the termination times and prove various class and distributional properties, facilitating tractable analysis of the risks. Extending this framework, we model random sums where aggregate claims are sums of continuous phase-type random variables with counts determined by these termination times, and show that their joint distribution belongs to the multivariate phase-type or matrix-exponential class. We develop estimation procedures for the CDPH distributions using the expectation-maximization algorithm and demonstrate the applicability of our models through simulation studies and an application to bivariate insurance claim frequency data.
title Modeling discrete common-shock risks through matrix distributions
topic Statistics Theory
url https://arxiv.org/abs/2502.21172