Wis. Stat. § 180.0142: Number of shareholders.

(1) For purposes of this chapter, any of the following constitute one shareholder if identified as a shareholder in a corporation’s current record of shareholders:

(a) Three or fewer co-owners.

(b) An entity.

(c) The trustees, guardians, custodians or other fiduciaries of a single trust, estate or account.

(2) For purposes of this chapter, shareholdings registered in substantially similar names constitute one shareholder if it is reasonable to believe that the names represent the same person.