BIS issues temporary final rule on polysilicon stockpiling under Proclamation 11052

BIS issued a temporary final rule, effective September 22, 2026 through December 3, 2026, setting the criteria and process it will use to monitor existing companies for evidence of stockpiling polysilicon and polysilicon derivatives ahead of import adjustments effective December 4, 2026 under Proclamation 11052. The rule limits a newly established importer's ability to stockpile, imposes import limitations on new importers that register with CBP on or after August 6, 2026, and subjects companies found to be stockpiling to an import prohibition if necessary. It also establishes the process for such companies to obtain a waiver from any import prohibitions imposed under the rule.