Mich. Comp. Laws § 408.483a: Prohibited conduct.

Sec. 13a.

An employer shall not do any of the following:

Require as a condition of employment nondisclosure by an employee of his or her wages.

Require an employee to sign a waiver or other document which purports to deny an employee the right to disclose his or her wages.

Discharge, formally discipline, or otherwise discriminate against for job advancement an employee who discloses his or her wages.