S.D. Codified Laws § 51A-4-29
A bank or other banking organization, organized under the laws of this state, which has as one of its principal purposes the making or purchasing of loans secured by real estate mortgages, may make real estate mortgage loans in any form, including but not limited to variable rate mortgages, collateral real estate mortgages, renegotiated rate mortgages, and shared appreciation mortgages, unless otherwise prohibited by law and may, notwithstanding any other provision of law, sell such mortgage loans to the Federal National Mortgage Association, a corporation chartered by an act of Congress, or any successor thereof, and in connection therewith may make payments of any capital contributions, required pursuant to law, in the nature of subscriptions for stock of the Federal National Mortgage Association or any successor thereof, and may receive stock evidencing such capital contributions, and hold or dispose of such stock.
SDCL 51A-4-29