Wis. Stat. § 611.66: Exclusive agency contracts.

(1) General. Except under sub. (2), no corporation may enter into any contract whereby any person is granted or obtains directly or indirectly the exclusive right or privilege of soliciting, producing or receiving a fee or commission on all or substantially all of the insurance business of the corporation or on all or substantially all of the insurance business of the corporation in this state.

(2) Subsidiaries. Subsection (1) does not apply to contracts in which a corporation is the exclusive agent of its insurance subsidiary authorized under s. 611.26 (1) or in which the subsidiary is the exclusive agent of the corporation.