SDCL § 37-10-8: Presumption as to cost of doing business by retailer purchasing from manufacturer.

In the absence of the filing with the secretary of revenue of satisfactory proof of a lesser or higher cost of doing business, the cost of doing business by the retailer, who, in connection with the retailer's purchase, received not only the discounts ordinarily allowed upon purchase by a retailer, but also, in whole or in part, the discounts ordinarily allowed upon purchases by a wholesaler, shall be presumed to be eight percent of the sum of the basic cost of cigarettes and the cost of doing business by the wholesaler.