The United States has announced sweeping new trade measures under US polysilicon tariffs, introducing minimum import prices and a 15% tariff on several polysilicon derivative products starting December 4, 2026. President Donald J. Trump signed the proclamation on August 6, 2026, after a national security investigation under Section 232 of the Trade Expansion Act of 1962 concluded that imports of polysilicon and related products threaten US national security.
The measures cover polysilicon, ingots, wafers, solar cells and solar modules that enter the United States. The administration said the action is intended to strengthen domestic production of materials used in semiconductors, solar energy systems, defense technologies and artificial intelligence applications.
According to the proclamation, the Department of Commerce found that foreign government policies have contributed to global oversupply and weakened the US polysilicon industry. Global polysilicon production has increased by more than 270% since 2020, while inventories reached a record 400,000 tons by the end of 2024.
The report also found that the US share of global polysilicon production capacity fell from 50% in 2005 to less than 2% in 2024. Over the same period, the US share of semiconductor wafer fabrication capacity declined from 37% in 1990 to 10% in 2024. In the solar sector, the United States remains heavily dependent on imports of solar ingots, wafers and cells.
Key details of US polysilicon tariffs
Under the new US polysilicon tariffs framework, the government has established minimum import prices for several products. The minimum import price for polysilicon has been set at $21 per kilogram, while polysilicon ingots and wafers will face a minimum price of $100 per kilogram.
Solar cells will be subject to a minimum import price of $0.22 per watt, while solar modules will have a minimum price of $0.38 per watt. The Secretary of Commerce has been authorized to revise these prices in the future to reflect market conditions and fair market values.
Beginning at 12:01 a.m. eastern time on December 4, 2026, importers must provide documentation proving that the first arm’s-length sale in the United States will occur at or above the required minimum price. Products imported without such documentation will automatically face a tariff equal to the applicable minimum import price.
Even when documentation is submitted, products imported below the minimum threshold will face an additional charge equal to the difference between the declared value and the required minimum price.
The proclamation also imposes an additional 15% ad valorem duty on imports of polysilicon derivatives, including ingots and other covered products, effective from December 4, 2026. These duties will remain in place unless they are modified or terminated by the government.
Special provisions apply to imports from Japan, South Korea, Taiwan, Switzerland, Liechtenstein and European Union member states. For those countries, the combined Section 232 tariff and existing tariff rate under the Harmonized Tariff Schedule of the United States will equal 15%.
Products imported from the United Kingdom will face a 10% tariff under the new rules.
The administration has also introduced an onshoring incentive program aimed at encouraging companies to build, expand or refurbish facilities in the United States that produce raw polysilicon, ingots, wafers and cells. Companies seeking incentives must commit to starting construction by January 20, 2029.
Approved companies may receive temporary exemptions from Section 232 duties on production equipment and covered products during the construction period, subject to compliance with investment commitments and progress requirements.
The proclamation gives US Customs and Border Protection authority to monitor importer compliance. Companies that submit materially inaccurate documentation or fail to meet certification requirements could face permanent restrictions on importing polysilicon products into the United States, along with additional penalties permitted under law.
The Department of Commerce has also been directed to monitor stockpiling activity before the measures take effect and may impose restrictions on companies found to be accumulating products ahead of the December deadline.
The White House said the measures are designed to support domestic production of semiconductor-grade and solar-grade polysilicon, strengthen supply chains and address national security concerns linked to imports.
