Ghana operates a threetier social security system. The first two tiers are mandatory and the third is voluntary. Social security contributions are portable, that is they can be transferred from one social security scheme in one country to that in another country, and are to be paid in respect to both local and expatriate staff. The guidelines issued by the Social Security and National Insurance Trust exempt the following categories of expatriates from contributing to Tier 1:

•  Expatriate workers engaged on a short-term assignment; and
•  Expatriate workers who contribute to a pension scheme in their own home country, with evidence to be provided in the form of pay slips showing deductions made to the scheme.