Article 136 provides specific filing rules for foreign entities operating multiple branches (Permanent Establishments) in Oman. Such a person is required to file a single, consolidated tax return that encompasses the activities and financial results of all their Omani PEs. The total tax due is then determined based on the aggregate taxable income of all these establishments combined. This 'single-filer' approach prevents the artificial isolation of profits and losses among different branches of the same foreign person, ensuring a holistic assessment of their Omani business presence.