S.D. Codified Laws § 54-8-2
Every transfer of personal property other than a thing in action, which is not evidenced by a bill of sale filed in the office of the register of deeds of the county wherein such property is situated or of the county to which such county is attached for judicial purposes, and every lien thereon, other than a mortgage, when allowed by law is conclusively presumed, if made by a person having at the time the possession or control of the property and not accompanied by an immediate delivery and followed by an actual and continued change of possession of the thing transferred, to be fraudulent and therefore void against those who are his creditors while he remains in possession, and the successors in interest of such creditors, and against any person on whom his estate devolves in trust for the benefit of others than himself and against purchasers and encumbrancers in good faith subsequent to the transfer.
SDCL 54-8-2