Costs allocation in tax treaties: requesting party may bear extraordinary costs subject to prior consultation between competent authorities. Article 9 provides that ordinary costs of assistance are borne by the requested Party, while extraordinary costs are borne by the requesting Party when they exceed a specified threshold; competent authorities must consult in advance where extraordinary costs are likely to exceed that threshold and consult periodically regarding the Article. Examples of extraordinary costs include third party copying fees, interpreter or translator and expert fees, conveyance of documents, litigation costs related to a request, and costs for obtaining depositions or testimony.