A multivariate unsupervised lognormal-GPD mixture for dependent losses
Abstract
We propose a multivariate two-population mixture distribution for heavy-tailed and positively skewed non-negative data. The first mixture population is a multivariate lognormal, while the second is a distribution obtained by joining univariate zero-mean generalized Pareto densities via a Gumbel copula. The model is unsupervised, since no threshold has to be set or estimated. We derive some properties of the distribution and develop an Expectation-Conditional Maximization algorithm for maximum likelihood estimation, which is found to perform well in multivariate contexts beyond the bivariate case. The finite-sample properties of the estimators are assessed by means of simulation experiments, and an empirical application to aggregated commercial property-casualty insurance claims illustrates the impact of dependence on risk estimation. All the methods are implemented in the R package MultLognGPD, available on Github.
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BibTeX
@misc{bee2026multivariate,
title = {{A multivariate unsupervised lognormal-GPD mixture for dependent losses}},
author = {Marco Bee and Flavio Santi},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.02148},
eprint = {2611.02148},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.02148},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A multivariate unsupervised lognormal-GPD mixture for dependent losses
AU - Marco Bee
AU - Flavio Santi
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.02148
UR - https://arxiv.org/abs/2611.02148
AB - We propose a multivariate two-population mixture distribution for heavy-tailed and positively skewed non-negative data. The first mixture population is a multivariate lognormal, while the second is a distribution obtained by joining univariate zero-mean generalized Pareto densities via a Gumbel copula. The model is unsupervised, since no threshold has to be set or estimated. We derive some properties of the distribution and develop an Expectation-Conditional Maximization algorithm for maximum likelihood estimation, which is found to perform well in multivariate contexts beyond the bivariate case. The finite-sample properties of the estimators are assessed by means of simulation experiments, and an empirical application to aggregated commercial property-casualty insurance claims illustrates the impact of dependence on risk estimation. All the methods are implemented in the R package MultLognGPD, available on Github.
ER -