SDCL § 43-42-4: Accounts receivable--Transfer by assignment in good faith.

Every written assignment made in good faith, whether in the nature of a sale, pledge, or other transfer, of an account receivable or of an amount due or to become due on an open account or on a contract (all hereinafter called "account"), with or without the giving of notice of such assignment to the debtor, shall be valid, legal, and complete at the time of the making of such assignment, and shall be deemed to have been fully perfected at that time. Thereafter, no bona fide purchaser from the assignor, no creditor of any kind of the assignor, and no other assignee or transferee of the assignor, in any event shall have, or be deemed to have acquired, any right in the account so transferred or in the proceeds thereof or in any obligation substituted therefor, superior to the rights therein of the assignee.