(27)Where the depositary delegates custody tasks and the financial instruments held in custody by a third party are lost, the depositary should be liable. In the case of loss of an instrument held in custody, a depositary should return a financial instrument of an identical type or the corresponding amount, even if the loss occurred with a third party to which the custody has been delegated. The depositary should be discharged of that liability only where it is able to prove that the loss resulted from an external event beyond its reasonable control and with consequences that were unavoidable despite all reasonable efforts to the contrary. In that context, a depositary should not be able to rely on internal situations such as a fraudulent act by an employee to discharge itself of liability. No discharge of liability, be it regulatory or contractual, should be possible in the case of loss of assets by the depositary or a third party to which the custody has been delegated.