Permanent establishment rules determine when a foreign enterprise is taxable based on fixed place or dependent agent presence. A permanent establishment is a fixed place of business through which an enterprise carries on business, including specified examples and activities such as construction sites and service provision when temporal thresholds are exceeded. Preparatory or auxiliary activities (storage, display, stock maintenance for storage or processing, purchasing, information gathering) are excluded unless combined activities with the same or closely related enterprises are complementary and non-auxiliary. Agency rules deem an enterprise to have a permanent establishment where a person habitually concludes contracts or maintains a stock for delivery, subject to an independent agent exception; insurance activities conducted through a person also create a permanent establishment.