EN
To save myopic workers against themselves, the government introduces a mandatory system, but to help savers, it adds tax-favoured retirement accounts. Using a very simple model where benefits are proportional to contributions, the author compares three extreme systems: (i) the pure mandatory system, (ii) the asymmetric system, where only savers participate in the voluntary system, (iii) and the symmetric system, where both types participate proportionally to their wages. The symmetric voluntary system is welfare-superior to the asymmetric one, and to the pure mandatory system, which in turn are equivalent to each other.