R.I. Gen. Laws § 28-37-16: Returns and payments by certified employers.

Every certified employer shall, on or before May 15 of each year, except for the period ending June 30, 2000, when the return shall be due September 15, file with the director, in any form and containing any information that he or she may prescribe, a return under oath or affirmation signed by a duly authorized officer or agent of the company. The director shall then determine the payment to be made by each employer under this chapter and shall mail a notice of the amount of this payment to each certified employer. The determined amount shall be due and payable within sixty (60) days of notice.