<p>This paper simulates the redistributive implications of the parametric components of South Korea’s 2025 National Pension reform, focusing on the contribution-rate and replacement-rate increases. Using microsimulation based on the Korean Labor and Income Panel Study (KLIPS, 1997–2022), we construct individual lifetime net transfers, defined as the present value of lifetime pension benefits minus lifetime contributions, under the current system, the parametric components of the 2025 reform, and selected scenarios from the 2023 reform draft. We examine the sign structure of net transfers, inequality among net beneficiaries using the Mean Log Deviation (MLD), Theil index, and Gini coefficient, and MLD decompositions by cohort and income group. Because log-based inequality measures are defined only for positive net transfers, we supplement them with full-distribution summaries that include non-positive observations. Under the maintained assumptions, the current system and the 2025 reform’s parametric components are not associated with net contributors and imply only modest distributional changes. By contrast, pensionable-age increases are associated with a small number of net contributors, concentrated among individually insured persons, and wider dispersion. Contribution-history and longevity heterogeneity shift simulated inequality from mainly between cohorts to mainly within cohorts. Sensitivity checks affect the level of simulated net transfers but do not overturn the main ranking of scenarios. The results should be interpreted as a policy simulation of the reform’s parametric components, not as an evaluation of the full reform package.</p>