R.I. Gen. Laws § 28-40-9: Interest on delinquent payments.

Employers who fail to make payment of contributions, as required by chapters 39 — 41 of this title, or by the prescribed rules and regulations, shall be additionally liable to the temporary disability insurance reserve fund for interest on those delinquent payments at the rate of one and one-half percent (11/2%) per month from the date the payment became due until paid.