Prima de Antigüedad: Fundamentos Laborales y Fiscales

This paper analyzes seniority pay within the Mexican labor system, highlighting its legal nature as a minimum, irrevocable, and public order benefit, whose purpose is to recognize the worker's permanence and compensate for the loss of income resulting from the termination of the employment relationship. Based on the constitutional framework and the protective principles of labor law—pro-worker, non-waivable, and most beneficial condition—the normative foundations of Article 162 of the Federal Labor Law are examined, as well as the jurisprudential criteria that have broadened its scope in scenarios of unjustified dismissal, justified resignation, disability, retirement, and death (De Buen, 2019; De la Cueva, 2018; SCJN, 2017). Likewise, its tax treatment is explained in accordance with Article 93 of the Income Tax Law, which establishes an exemption scheme based on 90 UMAs per year of service, determining that the surplus constitutes taxable income subject to withholding. The analysis highlights the convergence between the labor and tax spheres to ensure certainty, proportionality, and fairness in the determination of severance pay, consolidating the protective function of social rights and reinforcing the economic security of workers at the end of their employment relationship.