(1) If notice of the assignment is given by the assignee, the obligor may request the assignee to provide within a reasonable time adequate proof that the assignment has been made.
(2) Until adequate proof is provided, the obligor may withhold payment.
(3) Unless adequate proof is provided, notice is not effective.
(4) Adequate proof includes, but is not limited to, any writing emanating from the assignor and indicating that the assignment has taken place.
Since receiving the notice of assignment has the important effects provided for in Articles 9.1.10 and 9.1.11, this Article intends to protect the obligor against the risk of receiving a fraudulent notice from a fake “assignee” by requiring adequate proof that the assignment has actually been made. Until adequate proof is provided, the obligor may withhold payment to the alleged assignee. If adequate proof is provided, notice is effective from the date it was provided.
On 1 December purchaser X has to pay USD 200,000 to contractor A as an instalment of the sum due for the construction of a plant. In October A assigns the right to bank B. Either A or B may give notice of the assignment to X. If B takes the initiative and writes to X that it has become the assignee of the sum, X may require B to provide adequate proof. Without prejudice to other types of evidence, B will probably produce the assignment agreement or any other writing from A confirming that the right has been assigned. Until such adequate proof is provided, X may withhold payment.