Michigan Compiled Laws, Chapter 421. Employment Security § 421.15a

Sec. 15a. (1) The unemployment agency shall not collect interest on a contribution obligation that an employer pays through apportioned quarterly payments, if the employer meets the requirements of section 13(3)  1 and has remitted the following amounts or more each quarter by the date established for each quarterly filing:

(2) If an employer fails in any quarter to pay in full, by the due date of the tax payment for that quarter, the percentage of the tax deferred from the first quarter as described in subsection (1), the unemployment agency may collect interest at the rate specified in section 15  2 on the amount of the deferred tax that is due in that quarter and unpaid.