Mich. Comp. Laws § 421.40
"Employing unit" means any individual or type of organization, including, but not limited to, a governmental entity as defined in section 50a, a partnership, association, trust, estate, joint-stock company, insurance company or corporation, whether domestic or foreign, or the receiver, trustee in bankruptcy, trustee or successor thereof, or the legal representative of a deceased person, which has or subsequent to this amendatory act, had in its employ 1 or more individuals performing services for it within this state. All individuals performing services within this state for any employing unit which maintains 2 or more separate establishments within this state shall be considered to be employed by a single employing unit for all the purposes of this act. Each individual employed to perform or to assist in performing the work of any agent or employee of an employing unit shall be considered to be employed by that employing unit for all the purposes of this act, whether the individual was hired or paid directly by that employing unit or by the agent or employee, provided the employing unit had actual or constructive knowledge of the work.
MCL 421.40