Business profits taxation: attribution to a permanent establishment under the arm's length principle governs taxable income allocation. Taxation of business profits is governed by attribution to a permanent establishment: profits taxable in the residence State unless attributable to such an establishment in the other State, where only profits linked to that establishment, similar local sales, or similar activities may be taxed. Attribution must reflect the arm's length principle, allowing deductions for expenses incurred for the permanent establishment subject to local tax law and specified limitations, while excluding non reimbursement payments to or from head office (royalties, fees, commissions, management charges, and, except for banks, interest). Apportionment customs may continue if consistent with the Article; mere purchase for export does not attribute profits.