Mich. Comp. Laws § 38.556e: Mandatory subjects of bargaining.

Sec. 6e.

Notwithstanding any other provisions of this act, any matter relating to the retirement system provided by this act, including, but not limited to, postretirement adjustment increases, applicable to current employees represented by a collective bargaining agent is a mandatory subject of bargaining under the public employment relations act, Act No. 336 of the Public Acts of 1947, being sections 423.201 to 423.216 of the Michigan Compiled Laws.