We study Social Security legislated endogenously by altruistic, overlapping generations. Starting from a steady-state equilibrium without Social Security, both generations living in a period can gain from legislation that mandates transfers from young to old in that and all subsequent periods. The Social Security allocation is Pareto-optimal. Later living pairs of generations may lose, but do not amend the law.

The authors study social security legislated endogenously by altruistic, overlapping generations. Starting from a steady-state equilibrium without social security, both generations living in a period can gain from legislation that mandates transfers from young to old in that and all subsequent periods. The social security allocation is Pareto optimal. Later living pairs of generations may lose, but do not amend the law.