South Dakota sets no limits on small loan interest rates and permit payday loans by omission.

10-43-1. Definition of terms. Terms used in this chapter mean:

(1) "Corporation," joint stock companies, limited partnerships, limited liability companies, and associations organized for pecuniary profit;

(a) "Domestic corporation," any corporation organized under the laws of this state;

(b) "Foreign corporation," any corporation other than a domestic corporation;

(2) "Depository," any bank with deposits insured under the Federal Deposit Insurance Act, any institution with accounts insured by the federal savings and loan insurance corporation, or any thrift or home financing institution which is a member of a federal home loan bank; any other bank or thrift institution, incorporated or organized under the laws of any state, which is engaged in the business of receiving deposits; or any company, organized or created under the laws of a foreign country, which maintains or owns a branch or subsidiary in the United States receiving deposits;

(3) "Dividend," any distribution made by a corporation out of its earnings or profits to its shareholders or members, whether in cash or in other property of the corporation;

(4) "Financial institution," any banking institution or savings and loan association organized under the laws of the United States and located or doing business in this state; any bank, savings and loan association, mutual saving bank, or trust company, organized under the laws of this state or of any other state, district, territory, or country, doing business within this state; any person licensed in this state pursuant to chapter 54-4, the installment repayment small loan and consumer finance law; and any person in the business of buying loans, notes, or other evidences of debt except those persons registered as broker-dealers pursuant to chapter 47-31A; and persons in the business of making installment repayment and open-end loans which may be unsecured or secured by real or personal property, which loans are in an aggregate amount exceeding five hundred dollars, which are repaid in two or more installment payments or one lump sum payment extending over a time exceeding thirty days from the day the loan was made except where the loan is made by the person selling the property, incidental to the sale of the property and where the seller is primarily in the business of selling such real or personal property or except where the loan is made to a related corporation and the primary business of these related corporations is the production and sale of tangible personal property or where the loan is made in the form of an advance to secure the production of equipment to be obtained by the lender or to finance a joint venture between the lender and others which has been formed to produce and sell tangible personal property;

(5) "Fiscal year," an accounting period of twelve months, ending on the last day of any month other than December;

(6) "Foreign country," any jurisdiction other than one embraced within the United States. "United States," when used in a geographical sense, includes the states, the District of Columbia, and the possessions of the United States;

(7) "Income year," the calendar year or the fiscal year upon which the net income is computed;

(8) "Individual," a natural person;

(9) "Paid," for the purposes of the deductions means paid or accrued or paid or incurred, and the terms paid or incurred and paid or accrued are construed according to the accounting method used for computing net income; received, for the purpose of the computation of net income means received or accrued, and the term received or accrued is construed according to the accounting method used for computing net income;

(10) "Person," includes individuals, firms, associations, limited liability companies,
corporations, estates, fiduciaries, and all entities from which income tax may be due. In no event shall a pass-through entity owned in whole or in part, directly or indirectly, by a financial institution subject to tax under this chapter, and formed primarily to facilitate the securitization of assets, be treated as a person for the purpose of subdivision 10-43-1(4);

(11) "Related corporation," a corporation associated with another as its parent or subsidiary, or in a brother-sister relation;

(12) "Taxable income," all net income;

(13) "Taxpayer," includes any person, corporation, or fiduciary who is subject to a tax imposed by this chapter;

(14) "Tax year," the calendar year, or the fiscal year ending during a calendar year, used for computing net income.
54-6-20. Maximum payment periods of small loan contracts. No licensee may enter into any contract of loan under this chapter under which the borrower agrees to make any payment of principal more than twenty-four and one-half calendar months from the date of making such loan in the case of loans having a principal sum of one thousand dollars or less; thirty-six and one-half calendar months for loans having a principal sum of more than one thousand dollars, but not exceeding two thousand five hundred dollars; or sixty and one-half calendar months for loans having a principal sum of more than two thousand five hundred dollars, but not exceeding five thousand dollars.

54-6-3. Charges on small loans -- Advance receipt -- Unpaid principal balance of prior loan. Charges on loans made under this chapter shall not be paid, deducted or received in advance. Such charges shall not be compounded; provided, that if part or all of the consideration for a loan contract is the unpaid principal balance of a prior loan, then the principal amount payable under such loan contract may include any unpaid charges on the prior loan which have accrued within sixty days before the making of such loan contract.
54-6-4. Charges on small loans -- Computation. Such charges shall

(1) be computed and paid only as a percentage per month of the unpaid principal balance or portions thereof,

(2) be so expressed in every obligation signed by the borrower, and

(3) be computed on the basis of the number of days actually elapsed. For the purpose of computing charges, whether at the maximum rate or less, a month shall be any period of thirty consecutive days and the rate of charge for each day shall be one thirtieth of the monthly rate.
54-6-5. Charges on small loans -- Additional fees and charges includable in principal. In addition to the charges provided for in § § 54-6-2 to 54-6-4, inclusive, no further or other amount whatsoever shall be directly or indirectly charged, contracted for, or received, except that the additional charges otherwise allowed by this chapter and as follows may be contracted for, received and included in the principal amount of the loan: (1) lawful fees paid to a public official for filing, recording or releasing any instrument securing a loan and (2) fees actually incurred in connection with a loan secured by real estate (including fees or premiums for title examination, title insurance and appraisal fees).
54-6-6. Charges on small loans -- Loan contract payable in equal and consecutive monthly installments of principal and charges -- Precomputation of charges, application of payments. Repealed by SL 1982, ch 344, § 3.
54-6-7. Charges on small loans -- Loan contract payable in equal and consecutive monthly installments of principal and charges -- Precomputation when loan made, added to principal of loan. Repealed by SL 1982, ch 344, § 4.
54-6-42. Loans made outside of state -- Enforcement. No loan exceeding the maximum amount that may be loaned under this chapter, made outside this state for which a greater rate of interest, consideration or charges than is permitted by this chapter has been charged, contracted for or received, shall be enforced in this state and every person, in anywise participating therein in this state, shall be subject to the provisions of this chapter, provided, that the foregoing shall not apply to loans legally made in any state under and in accordance with a regulatory small loan law similar in principle to this chapter.