R.I. Gen. Laws § 27-8-4: Classification of risks by mutual companies.

Any mutual insurance company incorporated by this state and any mutual insurance company incorporated by any other state or country authorized to transact business in this state may classify the property and risks insured in it at the time of issuing policies on the property, and may issue policies upon that property and those risks under different rates of premium or premium deposit, corresponding as nearly as may be to the greater or lesser risk from the causes insured against and the loss that may attach to the several assumed risks, and the directors of any mutual insurance company may, by vote, fix and determine the percentage of dividend or unused or unabsorbed premium or premium deposit return to be paid or credited on expiring policies, which percentages may differ, following the different loss experience of different classes of risks of the same term. But all policies insuring risks in the same classification shall have an equal rate of dividend or return of unused or unabsorbed premium or premium deposit upon expiration, and in case of an assessment, the rate may be different for each different class of risks.