Permanent establishment rules define fixed place and dependent agent tests that determine tax presence and attribution of business activities. A permanent establishment is a fixed place of business through which an enterprise carries on business, with examples including management offices, branches, factories, warehouses providing storage for others, extraction sites, ships or rigs used for exploration, farms and construction projects that exceed the applicable duration threshold. Exclusions cover facilities used solely for storage, display, delivery, stock maintenance for processing by another, purchasing or information collection, and other preparatory or auxiliary activities or combinations thereof. Agency provisions deem an enterprise to have a permanent establishment where a person habitually concludes contracts, maintains stock for delivery, or secures orders substantially for the enterprise, while independent agents acting in the ordinary course of business do not create such an establishment; insurance activities soliciting premiums or insuring risks through non-independent persons are also treated as creating a permanent establishment except for reinsurance.