(1)    Generally; presence of objecting member. Unless the articles or bylaws provide otherwise and except as provided in sub. (2m), a quorum for the transaction of business at a members’ meeting is 10 percent of the total number of members for a cooperative with 100 or less members and 15 percent of the total number of members for all other cooperatives. The attendance of a sufficient number of members to constitute a quorum shall be established by a registration of the members present at the meeting. The registration shall be verified by the chairperson of the board or the records officer of the cooperative and shall be reported in the minutes of the meeting. Any member who objects at the beginning of a members’ meeting to the transaction of business because the meeting is not lawfully called or convened and who fails to participate in the meeting after the objection may not be considered as present at the meeting for purposes of determining whether a quorum is present.

   (2)   Quorum for voting by mail or alternative ballot. Except as provided in s. 193.531 (2), in determining whether a quorum is present at a members’ meeting for purposes of conducting a vote on a question that members may vote on by mail or alternative ballot, the number of members physically present at the meeting shall be added to the number of members voting by mail or alternative ballot.

   (2m)   Quorum for votes by class or series. Except as otherwise provided in the articles or bylaws or a member control agreement, if a vote at a members’ meeting is open only to holders of a particular class or series of membership interests, a quorum for conducting the vote is a number of members holding 10 percent of the voting power of the class or series for a cooperative with 100 or less members and a number of members holding 15 percent of the voting power of the class or series for all other cooperatives.

   (3)   Meeting action invalid without quorum. An action taken or approved at a members’ meeting by vote of the members is invalid if a quorum is not present at the time of the vote, unless approval of the members is not required under this chapter, the articles, or the bylaws.