Wis. Stat. § 601.71
When the commissioner is satisfied that any nondomestic insurer which no longer has a certificate of authority in this state does or omits to do any act whereby the rights of policyholders who are residents of this state, or who hold contracts issued or delivered in this state, are adversely affected, or whereby its ability to carry out its contracts with those policyholders is impaired, the commissioner may, with the agreement of the attorney general, bring an action in the name of the state on behalf of all policyholders so situated for the purpose of enforcing their rights. The attorney general shall act as attorney for the state in the action and the expenses shall be borne as in other civil actions in behalf of the state. Upon service of the complaint the insurer shall file with the commissioner the names and addresses of all policyholders so situated. A notice of the action shall be mailed to every such policyholder either by the commissioner or by the insurer, as the commissioner determines. Any policyholder affected by the action may intervene.
Wis. Stat. § 601.71