Wis. Stat. § 344.16: Requirements as to self-insurers.

(1) Any person in whose name more than 25 motor vehicles are registered may qualify as a self-insurer by obtaining a certificate of self-insurance issued by the secretary as provided in sub. (2).

(2) The secretary may, upon the application of such a person, issue a certificate of self-insurance when satisfied that such person is possessed and will continue to be possessed of ability to pay judgments obtained against such person.

(3) Upon not less than 5 days’ notice and a hearing pursuant to such notice, the secretary may upon reasonable grounds cancel a certificate of self-insurance. Failure to pay any judgment within 30 days after such judgment has become final constitutes a reasonable ground for cancellation of a certificate of self-insurance.