Wis. Stat. § 180.0730: Voting trusts.

(1) One or more shareholders may create a voting trust, conferring on a trustee the right to vote or otherwise act for them, by signing an agreement setting out the provisions of the trust and transferring their shares to the trustee. The voting trust agreement may include any provision consistent with the voting trust’s purpose. When a voting trust agreement is signed, the trustee shall prepare a list of the names and addresses of all owners of beneficial interests in the trust, together with the number and class of shares each transferred to the trust, and deliver copies of the list and agreement to the corporation’s principal office.

(2) A voting trust becomes effective on the date that the first shares subject to the trust are registered in the trustee’s name.