Evaluating Transition Rules for Enhancing Fairness in Bonus–Malus Systems: An Application to the Saudi Arabian Auto Insurance Market

A Bonus–Malus System (BMS) is a ratemaking mechanism used in insurance to adjust premiums based on a policyholder’s claim history, with the goal of segmenting risk profiles more accurately. A BMS typically comprises three key components: the number of BMS levels, the transition rules dictating the m...

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Main Authors: Asrar Alyafie, Corina Constantinescu, Jorge Yslas
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Risks
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Online Access:https://www.mdpi.com/2227-9091/13/1/18
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author Asrar Alyafie
Corina Constantinescu
Jorge Yslas
author_facet Asrar Alyafie
Corina Constantinescu
Jorge Yslas
author_sort Asrar Alyafie
collection DOAJ
description A Bonus–Malus System (BMS) is a ratemaking mechanism used in insurance to adjust premiums based on a policyholder’s claim history, with the goal of segmenting risk profiles more accurately. A BMS typically comprises three key components: the number of BMS levels, the transition rules dictating the movements of policyholders within the system, and the relativities used to determine premium adjustments. This paper explores the impact of modifications to these three elements on risk classification, assessed through the mean squared error. The model parameters are calibrated with real-world data from the Saudi auto insurance market. We begin the analysis by focusing on transition rules based solely on claim frequency, a framework in which most implemented BMSs work, including the current Saudi BMS. We then consider transition rules that depend on frequency and severity, in which higher penalties are given for large claim sizes. The results show that increasing the number of levels typically improves risk segmentation but requires balancing practical implementation constraints and that the adequate selection of the penalties is critical to enhancing fairness. Moreover, the study reveals that incorporating a severity-based penalty enhances risk differentiation, especially when there is a dependence between the claim frequency and severity.
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spelling doaj-art-ac34902f654d4b74ab0d817bdc7c36dc2025-01-24T13:48:21ZengMDPI AGRisks2227-90912025-01-011311810.3390/risks13010018Evaluating Transition Rules for Enhancing Fairness in Bonus–Malus Systems: An Application to the Saudi Arabian Auto Insurance MarketAsrar Alyafie0Corina Constantinescu1Jorge Yslas2Department of Mathematical Sciences, Institute for Financial and Actuarial Mathematics, University of Liverpool, Liverpool L69 7ZL, UKDepartment of Mathematical Sciences, Institute for Financial and Actuarial Mathematics, University of Liverpool, Liverpool L69 7ZL, UKDepartment of Mathematical Sciences, Institute for Financial and Actuarial Mathematics, University of Liverpool, Liverpool L69 7ZL, UKA Bonus–Malus System (BMS) is a ratemaking mechanism used in insurance to adjust premiums based on a policyholder’s claim history, with the goal of segmenting risk profiles more accurately. A BMS typically comprises three key components: the number of BMS levels, the transition rules dictating the movements of policyholders within the system, and the relativities used to determine premium adjustments. This paper explores the impact of modifications to these three elements on risk classification, assessed through the mean squared error. The model parameters are calibrated with real-world data from the Saudi auto insurance market. We begin the analysis by focusing on transition rules based solely on claim frequency, a framework in which most implemented BMSs work, including the current Saudi BMS. We then consider transition rules that depend on frequency and severity, in which higher penalties are given for large claim sizes. The results show that increasing the number of levels typically improves risk segmentation but requires balancing practical implementation constraints and that the adequate selection of the penalties is critical to enhancing fairness. Moreover, the study reveals that incorporating a severity-based penalty enhances risk differentiation, especially when there is a dependence between the claim frequency and severity.https://www.mdpi.com/2227-9091/13/1/18Bonus–Malus systemoptimal relativitiestransition rulesrandom effects
spellingShingle Asrar Alyafie
Corina Constantinescu
Jorge Yslas
Evaluating Transition Rules for Enhancing Fairness in Bonus–Malus Systems: An Application to the Saudi Arabian Auto Insurance Market
Risks
Bonus–Malus system
optimal relativities
transition rules
random effects
title Evaluating Transition Rules for Enhancing Fairness in Bonus–Malus Systems: An Application to the Saudi Arabian Auto Insurance Market
title_full Evaluating Transition Rules for Enhancing Fairness in Bonus–Malus Systems: An Application to the Saudi Arabian Auto Insurance Market
title_fullStr Evaluating Transition Rules for Enhancing Fairness in Bonus–Malus Systems: An Application to the Saudi Arabian Auto Insurance Market
title_full_unstemmed Evaluating Transition Rules for Enhancing Fairness in Bonus–Malus Systems: An Application to the Saudi Arabian Auto Insurance Market
title_short Evaluating Transition Rules for Enhancing Fairness in Bonus–Malus Systems: An Application to the Saudi Arabian Auto Insurance Market
title_sort evaluating transition rules for enhancing fairness in bonus malus systems an application to the saudi arabian auto insurance market
topic Bonus–Malus system
optimal relativities
transition rules
random effects
url https://www.mdpi.com/2227-9091/13/1/18
work_keys_str_mv AT asraralyafie evaluatingtransitionrulesforenhancingfairnessinbonusmalussystemsanapplicationtothesaudiarabianautoinsurancemarket
AT corinaconstantinescu evaluatingtransitionrulesforenhancingfairnessinbonusmalussystemsanapplicationtothesaudiarabianautoinsurancemarket
AT jorgeyslas evaluatingtransitionrulesforenhancingfairnessinbonusmalussystemsanapplicationtothesaudiarabianautoinsurancemarket