Joint life endowment insurance is a life insurance that covers more than one dependent, where benefit payments are made upon death from one of the insured, and provide two benefits, namely as life protection and also future savings. Insurance companies must prepare funds as a premium reserve to anticipate losses and have difficulty paying compensation in the event of a claim in the future. One of the methods of determining premium reserves is the prospective method, but often the determination of premium reserves by the prospective method is still not appropriate, so the modification method is further used. This study aims to determine the amount of premiums and premium reserves in joint life endowment insurance using the Illinois method which uses the concept of a prospective method, where in determining premium reserves using the Illinois method the term of premium payment of insurance participants is limited to only 20 years of payment. Then the researcher compared the value of the premium reserve using the Illinois method with the value obtained using the prospective method. The conclusion obtained from this study is that the value of joint life endowment insurance premiums has increased based on age increase when starting insurance and joint life endowment insurance premium reserves always increase every year, until at the end of the time the reserve coverage will reach the same value as the amount of compensation. The value of premium reserves using the Illinois method provides a larger reserve size than the prospective method. This is because the determination by the Illinois method also pays attention to the issuer in the early years of coverage. Meanwhile, the determination by the prospective method is only based on the net premium.
Key words: joint life endowment insurance, premium reserves, propektif method, Illinois method.