(a) The membership of a mutual savings bank shall consist solely of every depositor or holder of a deposit account issued by the savings bank.
     (b) The members of a stock savings bank shall be only the owners of its capital stock. Jointly owned stock shall constitute one membership.
     (c) Any savings bank that had legal existence under another statute prior to the date of this Act and which, if it was a mutual, included borrowers as members or, if its ownership was evidenced by stock, included borrowers and depositors as members, or as non-voting members, may retain that membership structure by resolution of its board of directors to be included in its application for a savings bank charter under this Act. Otherwise, borrowers may not be members of a savings bank operating under this Act, and only mutual savings banks may include depositors as members.
     (d) Joint ownership of an account constitutes one membership.