Wis. Stat. § 19.86: Notice of collective bargaining negotiations.

Notwithstanding s. 19.82 (1), where notice has been given by either party to a collective bargaining agreement under subch. I, IV, or V of ch. 111 to reopen such agreement at its expiration date, the employer shall give notice of such contract reopening as provided in s. 19.84 (1) (b). If the employer is not a governmental body, notice shall be given by the employer’s chief officer or such person’s designee.