SDCL § 55-13-11: Other property subject to depletion.

Except as provided in §§ 55-13-9 and 55-13-10, if the principal consists of property subject to depletion, including leaseholds, patents, copyrights, royalty rights, and rights to receive payments on a contract for deferred compensation, receipts from the property, not in excess of five percent per year of its inventory value, are income, and the balance is principal.