Provisional assessment requires a bond and timely document production, with finalization expected within a set compliance period. A proper officer may direct a provisional assessment when verification or reassessment is not possible or further tests or documents are required; the officer estimates a provisional duty and the importer or exporter must execute a bond for the difference between provisional and final duty and may be directed to deposit up to twenty percent of the provisional duty. The bond requires payment of any deficiency and production of outstanding documents within one month or as extended. Provisional assessments should be finalized expeditiously, ordinarily within six months, with allowances for longer timeframes in complex multi-consignment imports.