This paper contains a quantitative analysis of the intra-generational distributive effects of old-age contributive pensions in the Spanish case. This analysis is carried out from virtual labour market histories simulated from observed transition rates among non-participation unemployment and employment and wage profiles. Given labour market histories, the distributions of pensions benefits which would prevail under alternative pension systems are computed. Moreover, some conjectures are put forward on the likely effects of each pension system on labour supply and, hence, on labour market profiles and the resulting distributions of pensions taken into account these effects are also computed. The main conclusion from this exercise is that the current Spanish system of oldage contributive pensions, a defined-benefit system under which pension benefits depend on contributions during the last 15 working years, yields a higher degree of intra-generational inequality than other systems which would take into account longer periods to compute pension benefits or than defined-contribution systems.

Key words: contributive pensions, intra-generational distribution, labour supply incentives.
JEL classification: H55, D31.