Joint liability in contracts: ruling against the end of a two-year time limit for the social security contribution claim

With ruling no. 18004/2019, the Court of Cassation intervened on the subject of joint liability of the client for the contractor's contributory payments towards I.N.P.S., pursuant to art. 29, c. 2, of Legislative Decree 276/2003.
This rule, in the version in force at the time of the facts of the case, prior to the changes made in 2012, provides that "in the case of works or service contracts, the contractor or employer is jointly and individually liable with the contractor, as well as with any subcontractors within the limit of two years from the termination of the contract, to pay workers the salary and the social security contributions due".
The controversial issue on which the Supreme Court (SC) ruled, relates, in particular, to the applicability or not of the two-year limitation period from the termination of the contract, provided for in said provision, to exercise, regarding I.N.P.S. (the national social welfare institution), the action of ascertaining the contributory obligation towards the client, judged jointly.
The SC, in accepting the first reason for the appeal by cassation, considered “applicable to the case the general regulation of the contributory obligation which does not provide for any deadline for exercising the action to ascertain the contributory obligation, subject only to the prescribed term", stating, therefore, the following principle: "the two-year deadline set by Legislative Decree no. 276 of 2003, art. 29, paragraph 2, is not applicable to the action promoted by the social security institutions, subject only to the prescription”.
To this conclusion, the S.C. was received taking into consideration, first of all, the jurisprudence of the same Court according to which the salary and social security treatment relate to two distinct relationships, however much they may be connected, and observing, then, that the contributory obligation, “derives from the law and is under the responsibility of I.N.P.S., has an unavailable nature and must be commensurate with the salary that would be due to the worker on the basis of the current collective bargaining (so-called minimal contribution). Therefore, it can be asserted that the purpose of financing the insurance social security management establishes an inherent and necessary relationship between the remuneration due according to the parameters of the social security law and the tax claim of the body responsible for the implementation of social security protection” (EB).