Search

Traditionally, experience ratemaking is in principle based on the idea of Buhlmann’s credibility theory that, except for net premiums, was rarely applied to other premium calculation principles. This article uses Buhlmann’s credibility procedure to estimate moment-generating functions (MGFs) of risks and then deduces estimates of moments of those risks. For the premium calculation principles that can be expressed as functions of certain moments or more directly of the MGFs, this article develops a new type of experience ratemaking methods by means of the estimated MGFs and discusses their consistency and asymptotic normality. Numerical simulation shows that, under the Esscher and exponential premium principles, the new credibility estimates are better than existing credibilityestimates in the literature.

The generalized weighted premium includes many classical premium principles. Most important of all, some of them have positive safe-loading. Some work had been done previously, the credibility premium derived under this premium principle cannot be applied to practice directly due to the difficulties of calculation and the estimation of structure parameters. In this article, we consider a new form of credibility estimator under the generalized weighted premium principle. In addition, the consistency of the estimator is shown and the comparisons were analyzed with previous results in the simulations. The results show that this “new” estimator is better than existed estimators under mean square error sense. Finally, the structure parameters in credibility factor were estimated in the models of multitude contracts.

In almost all credibility models considered previously, the claims are assumed to be independent over risks. However, from the practical point of view, it is not always the case, and hence, in this article, we investigate the credibility premiums when risks are allowed to be generally dependent. Firstly, we re-build the credibility estimators for Buhlmann and Buhlmann–Straub credibility models under general dependence structure over risks. The methods are then extended to the regression credibility models.