Wis. Stat. § 102.62
In case of liability under s. 102.57 or 102.60, the liability of the employer shall be primary and the liability of the insurance carrier shall be secondary. If proceedings are had before the division for the recovery of that liability, the division shall set forth in its award the amount and order of liability as provided in this section. Execution shall not be issued against the insurance carrier to satisfy any judgment covering that liability until execution has first been issued against the employer and has been returned unsatisfied as to any part of that liability. Any provision in any insurance policy undertaking to guarantee primary liability or to avoid secondary liability for a liability under s. 102.57 or 102.60 is void. If the employer has been adjudged bankrupt or has made an assignment for the benefit of creditors, if the employer, other than an individual, has gone out of business or has been dissolved, or if the employer is a corporation and its charter has been forfeited or revoked, the insurer shall be liable for the payment of that liability without judgment or execution against the employer, but without altering the primary liability of the employer.
Wis. Stat. § 102.62