Mich. Comp. Laws § 125.2119

Sec. 19. An exemption or credit granted to a qualified business shall continue until the certification of the qualified business is revoked, as provided in this act, or for 10 years from the date that the business is certified as a qualified business. Even if approval of an enterprise zone is revoked by the authority as provided in this act, an exemption or credit granted to a qualified business located in that enterprise zone shall continue until revoked or until the 10-year or other specified period elapses.