Income tax is levied on net income at progressive rates. Profits of foreign enterprises are taxed at a flat rate. The principal indirect taxes are customs duties and a turnover tax. In 1982, a tax on gross gaming revenue was added on top of the normal profits tax. The Seychelles operates as a tax haven. It applies a territorial basis of tax assessment to corporations, so they are taxed only on the income that is derived directly from the country. The makes it an inviting place for international companies to headquarter, because the profits made by branches are not imputed to the center for tax purposes. Also the government imposes no personal income tax, although it does require social security contributions.