(5)To strengthen the depositaries' standing in relation to third parties to whom the custody of assets is delegated, that relationship should be documented by a written delegation contract. That contract should allow the depositary to take all the necessary steps for ensuring that the assets kept in custody are properly safeguarded and the third party complies at all times with the delegation contract and the requirements of Directive 2009/65/EC and Delegated Regulation (EU) 2016/438. Furthermore, the depositary and the third party should formally agree whether the third party is allowed to further delegate the custody functions. In that instance, the contract between the delegating third party and the third party to whom the custody functions are further delegated should be subject to the rights and obligations which are equivalent to those established between the depositary and the delegating third party.