Section 47-6-5a - Interest charges on loans repayable in installmentsExcept in cases where it is otherwise specially provided by law, parties may contract for and charge interest for a secured or unsecured loan, repayable in installments at a rate not in excess of:
(a) Six percent per annum upon the principal amount of the loan, for the entire period of the loan, and add such charge to the principal amount of the loan; or (b) six percent per annum upon the face amount of the instruments evidencing the obligation to repay the loan, for the entire period of the loan and deduct such charge in advance but in no case shall the interest on such a discount loan exceed an annual percentage rate of fifteen percent per annum calculated according to the actuarial method: Provided, That upon prepayment in full of a precomputed loan, the creditor shall rebate that portion of such charge in the manner set forth in section five-d of this article. Any note evidencing any such installment loan may provide that the entire unpaid balance thereof at the option of the holder shall become due and payable upon default in the payment of any stipulated installment without impairing the negotiability of such note if otherwise negotiable. Nothing herein contained shall affect or restrict the right of the parties under section five of this article to contract in writing for the payment of interest for the loan or forbearance of money at a rate not to exceed eight dollars upon one hundred dollars a year, and proportionately for a greater or less sum, or for a longer or shorter time, including points expressed as a percentage of the loan divided by the number of years of the loan contract.