Every insurance companies certainly have a capacity limit related to the maximum claim that can be borne. Therefore, insurance companies need to reinsure risks that cannot be borne to reinsurance companies. Types of reinsurance contracts that commonly used are quota-share and stop-loss. In quota-share reinsurance, the reinsurance premium is proportional by the proportion of amount claim that is covered, but this reinsurance is not safe against a large claim. While for stop-loss reinsurance, the reinsurance premium is relatively large but safe for a large claim. So, this undergraduate thesis will combine both types of reinsurance, in the hope that both can cover each other's shortcomings with their respective strengths. After being combined, it is necessary to determine the optimal quota-share proportion and stop-loss retention so insurance companies can calculate surely the number of risks they bear. One criterion of determines optimal proportion and retention is based on Value-at-Risk (VaR) optimization. The more minimum VaR value produced, the loss from claims that must be approved by the insurance company is getting smaller. With the reinsurance premium as a constraint, this optimization problem is solved for each type of reinsurance combination, be it stop-loss after quota-share or quota-share after stop-loss. From each of these types combinations, the result is optimal quota-share proportion and stop-loss retention, so as produce a minimum VaR value from the borne risk by insurance companies. By comparing the results of VaR optimization of these types of reinsurance, a combination quota-share after the stop-loss is obtained resulting in a more minimum VaR value.
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