(16)It is desirable to lay down rules defining the preconditions under which a management company may delegate, on the basis of mandates, specific tasks and functions to third parties so as to increase the efficiency of the conduct of its business. In order to ensure the correct functioning of the principle of the home Member State supervision, Member States permitting such delegations should ensure that the management company to which they granted authorisation does not delegate the totality of its functions to one or more third parties, so as to become a letter-box entity, and that the existence of mandates does not hinder an effective supervision over the management company. However, the fact that the management company has delegated its functions should not affect the liabilities of that company or of the depositary vis-à-vis the unit-holders and the competent authorities.