Preventive protection, legal characterisation and proportionality of the social security surcharge: an analysis considering the case law of the Supreme Court’s fourth Chamber

Abstract

This article offers a comprehensive analysis of the surcharge on Social Security benefits, a unique institution within the Spanish labour law system. Building from its hybrid legal nature -both punitive and benefit-based- the study examines its constitutional foundation, preventive function, and compensatory scope, together with the legal limits of insurability. The regulatory framework set out in Article 164 of the Recast General Social Security Act and its link with the Occupational Risk Prevention Act are explored in depth, paying special attention to the criteria used to determine the percentage of the surcharge -between 30% and 50%- in the absence of explicit statutory guidance. Recent case law of the Spanish Supreme Court plays a pivotal role in defining business liability, ensuring proportionality, and clarifying responsibility in subcontracting and outsourcing structures, rejecting automatic liability based solely on premises ownership. The article concludes that the surcharge remains a key protective mechanism that reinforces workplace safety and strengthens the principle of preventive responsibility in the Spanish legal system.