Mich. Comp. Laws § 21.201

Sec. 1. That upon all sums paid into the state treasury upon account of the principal of any of the educational funds, except where the provision is or shall be made by law, the state treasurer shall compute interest from the time of the payment, or from the time of the last computation of interest on the payment, to the first Monday of April in each year, and shall give credit on the interest to each fund, as the case may be; and the interest shall be paid out of the specific taxes.