An agent can never have authority, either actual or ostensible, to do an act which is, and is known or suspected by the person with whom he deals to be, a fraud on the principal.
S.D. Codified Laws § 59-3-8
Agent cannot have authority to defraud principal
Source: CivC 1877, § 1345; CL 1887, § 3968; RCivC 1903, § 1664; RC 1919, § 1246; SDC 1939, § 3.0208.
Official source: South Dakota Legislature. Reproduced from public-domain South Dakota statutes; confirm against the official source for the current text. Not legal advice.