The CPF (Central Provident Fund) is Singapore 's social security system. Established in 1955, it is mandatory for all Singapore citizens and permanent resents. The CPF is essentially a savings system where the worker contributes a certain percentage of their salary (20 % until the age of 55, 12.5% from 55-65, and then 7.5% thereafter), and the employer also making a contribution (10% until you're 55, 4% from 55-60, then 2% until you retire). You can withdraw certain amounts from this fund for certain reasons only (e.g. medical emergencies, buying a home & investing in stock), but its main purpose is to ensure that everyone has an adequate sum on which to retire.

Foreign nationals are not required to contribute to the CPF, although professionals who enter on a work permit and then become Permanent Residents will be expected to make contributions at the same rate as Singapore citizens. For the first two years of permanent residency your contributions are subsidised.