The scope of an insurer's subrogation rights becomes a contentious issue when the insured amount is less than the total value of the insurance, and the rights of the insured victim are diminished due to their comparative negligence. In a significant en banc decision, the Supreme Court of Korea shifted the established precedent by transitioning to the concept of negligence set-off after deduction in calculating damages for victims who have received benefits from public insurance, particularly National Health Insurance and Industrial Accident Compensation Insurance. According to this revised ruling, when a victim who has received insurance benefits claims damages for tort against a wrongdoer, if the victim's negligence contributed to the damage, the amount of the insurance benefits shall be deducted first, and then the amount of damages shall be calculated by offsetting the negligence with the remaining damages. This approach aims to fully protect the victim and fulfill the objectives of the social security system. In such scenarios, the insurer's right to subrogate the victim's claim against the wrongdoer is limited to the proportion of the insured amount that corresponds to the wrongdoer's liability. Comparing cases in which the victim's negligence is the sole cause of the injury with cases in which the victim's negligence or a pre-existing condition contributed to the injury, the doctrine seems to take into account the interests of the insurer and the victim. However, it needs to be complemented by legislation and policy in the future, as this doctrine seems less natural in the interpretation of the text of the National Health Insurance Act and the Industrial Accident Compensation Insurance Act, and that it requires additional financial resources as it increases the burden on the state as the insurer.