International legal justification for the differentiation of insurance premium rates by types of social risks in pension insurance

The subject of the research is the international legal justification for the differentiation of insurance rates by types of social risks in mandatory pension insurance systems. Special attention is given to the study of the principle of equivalence of insurance contributions as a fundamental requirement of the insurance model and its correlation with various forms of tariff differentiation: by professional risk, age, income, region, and the intended purpose of contributions. The Russian mandatory pension insurance system is examined separately, where a unified rate is applied, and the maximum limit of the contribution base breaks the connection between the paid contributions and the accrued pension rights. The subject of the research also covers gender aspects of ILO Convention No. 102 and a critical analysis of two draft laws (from 2022 and 2026) aimed at eliminating the inconsistencies of the Russian system with international standards. The methodology of the research includes a comparative legal method, supplemented by a formal legal analysis of regulatory acts, actuarial assessments of insurance risks, and a systemic approach to studying tariff models in their relation to the principle of equivalence. The scientific novelty lies in the systemic justification for the necessity to transition from a unified tariff to risk-oriented differentiation based on three types of pension risks (old age, disability, loss of breadwinner) according to international standards, as well as in identifying a unique mechanism in Russian practice for collecting contributions exceeding the maximum base without forming pension rights, which is qualified as a quasi-tax. Additionally, a critique is presented on the gender model of ILO Convention No. 102 as outdated, acknowledged by the ILO itself, while still maintaining its role as a benchmark for minimum standards. Conclusions: the principle of equivalence is not only a theoretical construct but also a practical criterion for the effectiveness of the pension system; its restoration in Russia requires the differentiation of tariffs based on three grounds for assigning insurance pensions, establishing actuarially justified rates, and restoring the direct connection between paid contributions and future pension rights. The implementation of such an approach will achieve a replacement ratio of no less than 40% and ensure the long-term financial sustainability of the system.