20 CFR § 404.1256 - Limitation on State's liability for contributions for multiple employment situations—for wages paid prior to 1987.
(a) Limitation due to multiple employment. Where an individual in any calendar year performs covered services as an employee of a State and as an employee of one or more political subdivisions of the State, or as an employee of more than one political subdivision; and the State provides all the funds for payment of the amounts which are equivalent to the taxes imposed on the employer under FICA on that individual's remuneration for those services; and no political subdivision reimburses the State for paying those amounts; the State's agreement or modification of an agreement may provide that the State's liability for the contributions on that individual's remuneration shall be computed as though the individual had performed services in employment for only one political subdivision. The State may then total the individual's covered wages from all these governmental employers and compute the contributions based on that total subject to the wage limitations in § 404.1047.
(b) Identification of employees in multiple employment. An agreement or modification of an agreement providing for the computation of contributions as described in paragraph (a) of this section shall identify the class or classes of employees to whose wages this method of computing contributions applies. For example, the State may provide that such computation shall apply to the wages paid to all individuals for services performed in positions covered by a particular retirement system, or to the wages paid to all individuals who are members of any two or more coverage groups designated in an agreement or modification. The State shall promptly notify SSA if the conditions in paragraph (a) of this section are no longer met by any class or classes of employees identified in an agreement or modification. In its notification, the State shall identify each class of employees and the date on which the conditions ceased to be met.
(c) Effective date. In the agreement or modification, the State shall provide that the computation of contributions shall apply to wages paid after the effective date stated in the agreement or modification. That date may be the last day of any calendar year; however, it may be no earlier than January 1 of the year in which the agreement or modification is submitted to SSA.