A crucial
assumption of the classical compound Poisson model of Lundberg (1903) for assessing
the total loss incurred in an insurance portfolio is the independence between
the occurrence of a claim and its claims size. In this paper we present a mixed
copula approach suggested by Song et al. (2009) to allow for dependency between
the number of claims and its corresponding average claim size using a Gaussian
copula. Marginally we permit for regression effects both on the number of incurred
claims as well as its average claim size using generalized linear models. Parameters
are estimated using adaptive versions of maximization by parts (Song et al. 2005).
The performance of the estimation procedure is validated in an extensive simulation
study. Finally the method is applied to a portfolio of car insurance policies,
indicating its superiority over the classical compound Poisson model.
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