Polysilicon stockpile ban under Proclamation 11052: what flagged IORs must do

On September 24, 2026, the Department of Commerce publishes a Temporary Final Rule (TFR) on measures to restrict stockpiling of polysilicon and polysilicon derivatives under Proclamation 11052 (FR Doc. 2026-19537). CSMS #69994928 tells importers and brokers how that TFR hits the border.

The operational trigger is not a blanket commodity ban for every IOR. Commerce flags specific importers of record. When Commerce informs CBP that an IOR is importing polysilicon products in volumes substantially greater than historic averages, or that a new IOR exceeds applicable weekly quantity limits, that IOR is thereafter prohibited from further entries of certain polysilicon products into the United States before December 4, 2026.

Flagged IORs cannot enter certain polysilicon products for consumption until December 4, 2026. Bonded warehouse movement remains available.

Legal hook: Proclamation 11052

The TFR implements Presidential Proclamation 11052, Adjusting Imports of Polysilicon and Its Derivatives Into the United States, published at 91 FR 51975 (August 6, 2026). The stockpile measures themselves are in the Commerce Temporary Final Rule at 91 FR 60505 (September 24, 2026; FR Doc. 2026-19537). CSMS #69994928 is CBP's filing guidance for those TFR procedures, not a second substantive proclamation.

What happens when Commerce flags an IOR

Two Commerce flags drive the CBP lock:

• Volume spike vs. historic average: Commerce determines the IOR is importing polysilicon products in volumes substantially greater than that IOR's historic averages.
• New IOR weekly limits: A new IOR exceeds the applicable weekly quantity limits for polysilicon products.

Once Commerce informs CBP, CBP will not allow that IOR to make entries of the covered products into the United States until December 4, 2026. Brokers should treat the flag as IOR-specific and product-specific under the TFR, not as a general ACE system outage.

Bonded warehouse vs. consumption entry

CSMS is explicit on the warehouse path. IORs subject to the restriction may move the goods to a bonded warehouse. They may not enter the goods for consumption before December 4, 2026.

Waiver path

Pursuant to the TFR, IORs prohibited from entering polysilicon products may apply to Commerce to waive the prohibition. CBP does not own the waiver decision. Direct importing-community questions to Commerce at Polysilicon232@bis.doc.gov.

If you are building a waiver package, lead with the IOR identity, product scope, shipment volumes versus historic averages (or new-IOR weekly limits), and the commercial reason the entry cannot wait until December 4. Keep CBP Client Representatives in the loop only after Commerce has a live request; CBP will enforce what Commerce tells it.

Drawback timing note

This measure is an entry prohibition for flagged IORs, not a drawback-eligibility rewrite. If merchandise never enters for consumption before December 4 (or before a waiver), there is no consumption entry to pair into a later drawback claim for that restricted window. Warehouse placement preserves custody; it does not create a consumption-duty baseline. Plan claims around accepted consumption entries only.

This article is for general information and is not legal or tax advice. Drawback eligibility depends on your specific facts, and final refunds are determined by CBP at liquidation. Consult a licensed customs broker or attorney for your situation.