Business profits taxation limited to residence unless permanent establishment permits taxation of attributable profits in source state Profits of an enterprise are taxable only in the State of residence unless the enterprise carries on business in the other Contracting State through a permanent establishment, in which case only the profits directly or indirectly attributable to that permanent establishment may be taxed there. Attribution treats the permanent establishment as a distinct and separate enterprise operating under similar conditions and dealing independently; allowable deductions include expenses incurred for the permanent establishment. Customary apportionment may be used if consistent with these principles, purchases alone do not create attributable profits, and the attribution method should be applied consistently year to year.