Measures to Restrict Stockpiling of Polysilicon and Polysilicon Derivatives under Proclamation 11052

What it does

• •Establishes monitoring procedures for existing importers of polysilicon and polysilicon derivatives to identify stockpiling in advance of December 4, 2026, when new minimum import prices and tariffs take effect, with enforcement by prohibiting further imports for identified stockpilers.
• •Sets weekly import volume limits for newly registered importers (those registered after August 6, 2026): 12 kg for HTSUS 2804.61.00, 7 kg for HTSUS 3818 categories, 2,000 units for HTSUS 8541.42.00, and 55 units for HTSUS 8541.43.00.
• •Creates a waiver application process allowing prohibited or restricted importers to request Commerce approval to resume or increase imports by demonstrating legitimate business purposes unrelated to stockpiling.
• •Requires customs brokers to monitor for and report violations, with potential enforcement actions including license suspension or revocation for brokers facilitating circumvention of the stockpiling restrictions.

Why it matters

• •The rule enforces Presidential Proclamation 11052, which found that polysilicon imports threatened national security and authorized import adjustments effective December 4, 2026; this temporary rule prevents companies from circumventing those adjustments by stockpiling inventory beforehand.
• •The measure addresses a specific vulnerability window between the proclamation's issuance (August 6, 2026) and the tariffs' effective date (December 4, 2026), during which importers could accumulate inventory to avoid higher future costs.
• •The waiver process allows for case-by-case relief where importers can demonstrate legitimate operational needs rather than speculative stockpiling, balancing national security concerns with normal commercial operations.

Who is affected

• •Existing importers of record (IORs) of polysilicon and polysilicon derivatives who may be subject to import prohibitions if Commerce determines they are importing volumes substantially greater than historic averages.
• •New importers of record registered with U.S. Customs and Border Protection on or after August 6, 2026, who face quantitative weekly import restrictions unless granted a waiver.
• •Customs brokers conducting business on behalf of affected importers, who bear affirmative obligations to avoid facilitating violations and face potential license revocation or penalties for non-compliance.

What happens next

This temporary final rule is effective September 22, 2026, through December 3, 2026, at which point the minimum import prices and tariffs from Proclamation 11052 take effect on December 4, 2026.