Fungible materials: accounting segregation allowed to manage origin status subject to accounting controls and documentation. Rule 9 permits physical segregation of identical originating and non originating materials during storage, or, where segregation is impracticable, allows an accounting segregation method. The accounting method must follow generally accepted accounting principles, distinguish clearly between originating and non originating materials, and prevent more products receiving originating status than under physical segregation. Producers must provide a sworn declaration, retain documentary evidence, and supply satisfactory information on stock management to competent authorities; prior authorisation may be required by the exporting Party.