Accounting segregation rules for fungible goods require physical separation, or approved inventory methods under applicable GAAP. Accounting segregation for fungible products or materials is ordinarily to be made by physical segregation. Where that is difficult, an inventory management method such as averaging, last-in, first-out or first-in, first-out may be used if recognised or accepted under the applicable GAAP. The method must be used consistently throughout the fiscal year, recorded and maintained in accordance with GAAP, clearly distinguish originating from non-originating materials, and ensure that no more products receive originating status than would result from physical segregation. Records must be kept for verification, and prior authorisation may be required.