Bilateral international tax treaties set the principles for taxation of international business. Under these, profits of a multi-national enterprise are taxable only in the country where the enterprise is resident. However, this rule is subject to an exception when the enterprise has a permanent establishment (PE) in another country. In that case, profits that are “attributable” to the PE may be taxed in the country where the PE is situated. The attribution of profits to PEs has always been subject to controversy as practices of countries and their interpretation have varied considerably. However, over the last several years a broad