Permanent establishment triggers local tax presence for enterprises operating through fixed places or dependent agents. Permanent establishment is a fixed place of business through which an enterprise carries on business, exemplified by management offices, branches, factories, warehouses and places of resource extraction. Time-based rules treat construction sites and service furnishing through personnel as permanent establishments only when duration thresholds are exceeded. Exclusions apply for preparatory or auxiliary activities, but collapse where combined activities with closely related enterprises are not preparatory or auxiliary. Dependent agents with contracting authority, regular stock for delivery, or habitually securing orders can create a permanent establishment; independent agents acting in the ordinary course do not.