S.D. Codified Laws § 5-18D-11
If a contract price for goods entered into by the state becomes unreasonable in view of changing market conditions, the Bureau of Human Resources and Administration may cancel the contract or adjust the contract price to meet the changing market conditions if it is necessary to obtain necessary supplies at the required time. Any contract price adjustment shall be justified in writing by the contractor to the Bureau of Human Resources and Administration and a copy of the adjustment and the written justification for the adjustment by the contractor and the bureau shall be filed with the auditor general. No contract price adjustment may allow for increased management costs or for an increase in the dollar amount of profit for the contractor having the contract. No contract price adjustment resulting in an increase may be made for or during the first ninety days of an annual contract.
SDCL 5-18D-11