Mich. Comp. Laws § 141.153
Notwithstanding the provisions of any other law, charter provision or ordinance to the contrary, any assessment made by a public corporation against any corporation, public or private, or any firm or person, or any contract obligation incurred by a public corporation, in anticipation of which bonds are to be issued, may bear any rate of interest, not exceeding 1 percentage point over the maximum rate at which the bonds or other evidences of indebtedness are to be offered for sale, determined by the governing body of the assessing or contracting public corporation at the time of assessment or contract obligation. If bonds or other evidences of indebtedness are subsequently issued in anticipation of the assessment or contract obligation, the rate of interest payable on the assessment or contract obligation shall be adjusted after the issuance to the rate required to produce an amount sufficient to pay the interest on the bonds or other evidences of indebtedness as they mature, but not exceeding 1 percentage point over the average rate of interest borne by the bonds or other evidences of indebtedness.
MCL 141.153