(17)When delegating safekeeping functions to a third party in accordance with Article 22a of Directive 2009/65/EC, the depositary is required to implement and apply an appropriate and documented procedure to ensure that the delegate complies with the requirements of Article 22a(3) of that Directive at all times. In order to ensure a sufficient level of protection of assets, it is necessary to set out certain principles that should be applied in relation to the delegation of safekeeping functions.