S.D. Codified Laws § 10-43-4
The liability for the tax imposed by this chapter shall arise upon the first day of each tax year and shall be based upon the net income assignable to this state at the rate of six percent on net income of four hundred million dollars or less; at the rate of five percent on net income exceeding four hundred million dollars but equal to or less than four hundred twenty-five million dollars; at the rate of four percent on the net income exceeding four hundred twenty-five million dollars but equal to or less than four hundred fifty million dollars; at the rate of three percent on the net income exceeding four hundred fifty million dollars but equal to or less than four hundred seventy-five million dollars; at the rate of two percent on the net income exceeding four hundred seventy-five million dollars but equal to or less than five hundred million dollars; at the rate of one percent on the net income exceeding five hundred million dollars but equal to or less than six hundred million dollars; at the rate of one-half of one percent on the net income exceeding six hundred million dollars but equal to or less than one billion two hundred million dollars; and at the rate of one-quarter of one percent on the net income exceeding one billion two hundred million dollars. The tax payable under this section may be no less than two hundred dollars.
SDCL 10-43-4