Wis. Stat. § 183.0401: Becoming member.

(1) If a limited liability company is to have only one member upon formation, the person becomes a member as agreed by that person and the organizer of the company. That person and the organizer may be, but need not be, different persons. If different, the organizer acts on behalf of the initial member.

(2) If a limited liability company is to have more than one member upon formation, those persons become members as agreed by the persons before the formation of the company. The organizer acts on behalf of the persons in forming the company and may be, but need not be, one of the persons.

(3) A person becomes an initial member of a limited liability company with the consent of a majority of the organizers. The organizers may consent to more than one person simultaneously becoming the company’s initial members.

(4) After formation of a limited liability company, a person becomes a member in any of the following ways:

(a) As provided in the operating agreement.

(b) As the result of a transaction effective under subch. X.

(c) With the affirmative vote or consent of all the members.

(d) As provided in s. 183.0701 (1) (c).

(e) As provided in s. 183.0503 (6) (c).

(5) A person may become a member without doing any of the following:

(a) Acquiring a transferable interest.

(b) Making or being obligated to make a contribution to the limited liability company.