19 C.F.R. § 10.415
(a) General. An importer claiming preferential tariff treatment for a good imported into the United States must maintain, for five years after the date of importation of the good, a certification (or a copy thereof) or other information demonstrating that the good qualifies as originating, and any records and documents that the importer has relating to the origin of the good, including records and documents associated with:
[CBP Dec. 05-07, 70 FR 10873, Mar. 7, 2005, as amended by CBP Dec. 06-39, 71 FR 76133, Dec. 20, 2006]