(6)In order to enable the depositary to fulfil its functions it is necessary to strengthen depositaries' oversight over the third parties, regardless of whether they are located inside or outside the Union. It should be required that depositaries verify whether financial instruments of AIFs are correctly recorded in the books of a third party and that the records kept are sufficiently accurate in order to be able to identify the nature, location and ownership of the assets held in custody. To facilitate effective fulfilment of the depositaries' duties, third parties should provide them with a statement on any change affecting the assets held in custody for the depositaries' AIF clients.