Michigan Compiled Laws, Chapter 500. Insurance Code of 1956 § 500.2438

Sec. 2438.  (1) Subject to rules and regulations which have been approved by the commissioner as reasonable, each rating organization shall permit any insurer, not a member, to be a subscriber to its rating services for any kind of insurance or subdivision thereof for which it is authorized to act as a rating organization.  Notice of proposed changes in such rules and regulations shall be given to subscribers.  Each rating organization shall furnish its rating services without discrimination to its members and subscribers.

(2) The reasonableness of any rule or regulation in its application to subscribers, or the refusal of any rating organization to admit an insurer as a subscriber, shall, at the request of any subscriber or any such insurer, be reviewed by the commissioner at a hearing held upon at least 10 days' written notice to such rating organization and to such subscriber or insurer.  If the commissioner finds that such rule or regulation is unreasonable in its application to subscribers, he shall order that such rule or regulation shall not be applicable to subscribers.

(3) If the rating organization fails to grant or reject an insurer's application for subscribership within 30 days after it was made, the insurer may request a review by the commissioner as if the application had been rejected.  If the commissioner finds that the insurer has been refused admittance to the rating organization as a subscriber without justification, he shall order the rating organization to admit the insurer as a subscriber.  If he finds that the action of the rating organization was justified, he shall make an order affirming its action.