Mich. Comp. Laws § 207.274: Minimum tax.

Sec. 4.

During the first year in which any property is subject to a specific tax under this act, the amount of the tax shall be not less than 75% of the ad valorem taxes levied and assessed against the property in the last year in which ad valorem taxes were levied and assessed against it; and during the second year in which the property is subject to the specific tax, the amount of tax shall be not less than 50% of the ad valorem taxes.