Subrogation is best known as a concept of insurance law. It can be applied outside the law of insurance, although the general laws against maintenance and champerty would otherwise prevent such an arrangement. When an insurer is required to pay a claimant a sum of money, it is almost always allowed to sue in the name of the claimant against any person who was responsible for the loss. This concept allows an insurance company to sue on behalf of its insured if it is required to pay the insured for a loss caused by another person.