S.D. Codified Laws § 46A-6-22
Every district maintaining a debt service fund for the payment of outstanding bonds shall keep the accumulations in the debt service fund deposited with the lawful depositories or invested in registered warrants or bonds of any municipal or public corporation of the state, or bonds, notes, or other obligations issued by any federal land bank, federal intermediate credit bank, bank for cooperatives, or any or all of the federal farm credit banks, or obligations of the United States, or bonds or securities of any kind issued by the state, and the interest accruing on the investment shall be credited to the debt service fund. Moneys in any debt service fund shall be invested only in the above-named securities as will become due and payable on or before the date when the bonds for the payment of which the debt service fund was created become due and payable, except bonds of the United States or of the state.
In carrying out the provisions of this section, all transactions shall be by resolution of the board of directors.
SDCL 46A-6-22