Usury

"Unless a maximum interest rate or charge is specifically established elsewhere in the code, there is no maximum interest rate or charge, or usury rate restriction between or among persons, corporations, limited liability companies, estates, fiduciaries, associations, or any other entities if they establish the interest rate or charge by written agreement. A written agreement is a document in writing, whether in physical or electronic form, in which the parties have demonstrated their agreement to the terms and conditions of an extension of credit, including the rate of interest. A written agreement includes the contract created by § 54-11-9. (SDCL § 54-3-1.1)

Under an obligation to pay interest, no rate being specified, interest is payable from date of incurrence of debt, unless the parties have otherwise agreed, at a maximum rate of the Category C rate of interest as established in § 54-3-16, and in the like proportion for a longer or shorter term. In the computation of interest for less than a year, three hundred sixty days are deemed to constitute a year. (SDCL § 54-3-4)

The official state interest rates, as referenced throughout the South Dakota Codified Laws, are as follows:

(1) Category A rate of interest is four and one-half percent per year;

(2) Category B rate of interest is ten percent per year;

(3) Category C rate of interest is twelve percent per year;

(4) Category D rate of interest is one percent per month or fraction thereof;

(5) Category E rate of interest is four percent per year;

(6) Category F rate of interest is fifteen percent per year; and

(7) Category G rate of interest is five-sixth percent per month or fraction thereof.

(SDCL § 54-3-16)"