29 C.F.R. § 103.40 Joint employers.
(a) An employer, as defined by section 2(2) of the National Labor Relations Act (the Act), is an employer of particular employees, as defined by section 2(3) of the Act, if the employer has an employment relationship with those employees under common-law agency principles.
(b) For all purposes under the Act, two or more employers of the same particular employees are joint employers of those employees if the employers share or codetermine those matters governing employees' essential terms and conditions of employment.
(c) To “share or codetermine those matters governing employees' essential terms and conditions of employment” means for an employer to possess the authority to control (whether directly, indirectly, or both), or to exercise the power to control (whether directly, indirectly, or both), one or more of the employees' essential terms and conditions of employment.
(d) “Essential terms and conditions of employment” are
(1) Wages, benefits, and other compensation;
(2) Hours of work and scheduling;
(3) The assignment of duties to be performed;
(4) The supervision of the performance of duties;
(5) Work rules and directions governing the manner, means, and methods of the performance of duties and the grounds for discipline;
(6) The tenure of employment, including hiring and discharge; and
(7) Working conditions related to the safety and health of employees.
(e) Whether an employer possesses the authority to control or exercises the power to control one or more of the employees' essential terms and conditions of employment is determined under common-law agency principles. For the purposes of this section:
(1) Possessing the authority to control one or more essential terms and conditions of employment is sufficient to establish status as a joint employer, regardless of whether control is exercised.
(2) Exercising the power to control indirectly (including through an intermediary) one or more essential terms and conditions of employment is sufficient to establish status as a joint employer, regardless of whether the power is exercised directly.
(f) Evidence of an entity's control over matters that are immaterial to the existence of an employment relationship under common-law agency principles and that do not bear on the employees' essential terms and conditions of employment is not relevant to the determination of whether the entity is a joint employer.
(g) A party asserting that an employer is a joint employer of particular employees has the burden of establishing, by a preponderance of the evidence, that the entity meets the requirements set forth in paragraphs (a) through (f) of this section.
(h) A joint employer of particular employees
(1) Must bargain collectively with the representative of those employees with respect to any term and condition of employment that it possesses the authority to control or exercises the power to control, regardless of whether that term or condition is deemed to be an essential term and condition of employment under this section for the purposes of establishing joint-employer status; but
(2) Is not required to bargain with respect to any term and condition of employment that it does not possess the authority to control or exercise the power to control.
(i) The provisions of this section are intended to be severable. If any paragraph of this section is held to be unlawful, the remaining paragraphs of this section not deemed unlawful are intended to remain in effect to the fullest extent permitted by law.