The US government has introduced a TFR to identify unusual import volumes for polysilicon and its derivatives to curb stockpiling ahead of December 4, 2026
Importers face weekly limits on polysilicon, wafers, cells and modules; companies can seek waivers from the restrictions
Roth expects enforcement to limit lower-priced inventory, while SEMA welcomed the measures as US manufacturers expand domestic production
The US Department of Commerce (DOC), along with the US Customs and Border Protection (CBP), has moved to curb stockpiling of polysilicon and polysilicon derivatives ahead of the 15% minimum import price (MIP) set to take effect under Section 232.
Through the Bureau of Industry and Security (BIS), the US government has introduced a Temporary Final Rule (TFR) setting out criteria and procedures to monitor companies for stockpiling. The rule allows the government to restrict imports if any evidence of such activity is identified.
Under the TFR, effective September 22, 2026 through December 3, 2026, the DOC will monitor imports by existing importers of record to identify companies whose volumes are substantially above historical levels.
The DOC will notify the CBP when it identifies such importers, after which CBP will notify the importer and relevant customs brokers conducting business on behalf of the existing importers of record (IOR). The affected importer can then be prohibited from making further entries of polysilicon products into the US before December 4, 2026.
The process requires the DOC to make the assessment on a case-by-case basis, considering import volumes since August 6, 2026, weekly averages since that date, historical weekly averages for January 1-August 6, 2026, and 2025, as well as the use of affiliates or newly established IORs.
The rule also places limits on newly established IORs. Companies registered with CBP on or after August 6 cannot import covered products above specified weekly quantities without Commerce approval. The weekly thresholds are 12 kg for polysilicon, 7 kg for specified wafer products, 2,000 units for cells and 55 units for modules.
Commerce and CBP will also take action against importers or customs brokers that establish or use multiple IORs or other arrangements to circumvent the restrictions.
The measures will also apply to customs brokers who facilitate importers and exporters in meeting federal requirements. According to the DOC, customs brokers that facilitate violations could face CBP enforcement, including penalties or suspension or revocation of their licenses.
Companies that are prohibited or restricted from importing polysilicon products into the US before the December deadline, can apply to the DOC for a waiver. Such applications will need to enter details including import volumes, ownership, manufacturing operations, intended use of the products and the business rationale for the imports. The department says it intends to respond to applications within 14 days.
The measures stem from Presidential Proclamation 11052 issued on August 6, 2026 that imposes a 15% tariff on imported polysilicon derivatives. It also establishes a minimum import price (MIP) for polysilicon and specified downstream products under Section 232 of the Trade Expansion Act of 1962. Those import adjustments are scheduled to take effect on December 4, 2026 (see US Announces 15% Tariff On Imported Polysilicon Under Section 232).
According to the DOC, import data from the week following the proclamation showed sharp increases in imports by some IORs compared with their historical weekly averages, indicating that stockpiling had already begun.
Commerce said import data showed sharp increases in polysilicon imports by some IORs, suggesting stockpiling had already begun. “This information suggests that importers are already stockpiling polysilicon and polysilicon derivatives and that time is of the essence in addressing this issue,” says the administration. It added that delaying the rule could allow further stockpiling and undermine the December 4 measures.
The Managing Director and Senior Research Analyst at Roth, Philip Shen said the ‘aggressive implementation’ of the 232 rules can help stop the importer from stockpiling solar products immediately and address a ‘key vulnerability’ in the proclamation.
Roth said strict enforcement of the anti-stockpiling rule could limit the availability of lower-priced inventory and support an expected 10–20¢/W increase in US module prices. Roth considers the TFR as a positive for local solar PV manufacturers First Solar, T1 Energy and TOYO.
Meanwhile, the Solar Energy Manufacturers for America (SEMA) Coalition welcomed the Commerce and CBP measures, saying, “Today’s action signals that Commerce intends to strictly police these practices by evaluating imports against historical levels over the past year and preventing ‘fly-by-night importers’ from establishing operations solely to stockpile products.” SEMA counts First Solar, Corning, Hemlock Semiconductor, Heliene, Wacker Chemie, Qcells among its members.
Nevertheless, Wacker Chemie has expressed concerns about the US measures. Reporting on the company’s recent Capital Markets Day, Reuters said Wacker CEO Christian Hartel called the MIP and tariffs announced by the US government “disappointing.” He said the measures, in their current form, do not encourage the use of US-made polysilicon.
Hartel said Wacker could continue operating its three US polysilicon sites serving the semiconductor and solar industries if domestic demand increases. Otherwise, the company may optimize its manufacturing footprint and focus on semiconductor-grade polysilicon.
SEMA also said its members are expanding US manufacturing operations, including cell production, and urged Commerce to engage with companies expanding domestic manufacturing and consider targeted waivers during the interim period.
