The U.S. has announced a 15% additional tariff on certain polysilicon products and set minimum import prices for polysilicon, wafers, and solar cells and modules, effective December 4, 2026, regardless of the country of origin.

President Donald Trump issued the proclamation after a U.S. Department of Commerce investigation under Section 232 of the Trade Expansion Act of 1962 found that polysilicon and related imports threatened national security.

The minimum import prices are $21/kg for polysilicon, $100/kg for polysilicon ingots and wafers, $0.22/W for solar cells, and $0.38/W for modules.

The Commerce Secretary can adjust prices to reflect market conditions or other factors that affect fair market value under non-distorted, free-market conditions.

Importers can submit documentation certifying that the first arm’s-length U.S. sale of covered products will occur at or above the relevant minimum import price. The program also covers fixed-term contracts entered into before the proclamation was signed.

Without the required documentation, polysilicon products will face a tariff equal to the applicable minimum import price. If the entered value is below the minimum price, the tariff will equal the difference.

U.S. Customs and Border Protection will monitor compliance with the minimum import price program. Importers and their affiliates could be permanently prohibited from importing covered products for materially inaccurate documentation or material noncompliance with certifications.

Additional 15% Tariff

Beginning December 4, polysilicon ingots and related products specified in the proclamation’s annexes will also face an additional 15% ad valorem tariff, subject to specified exceptions.

For products from Japan, South Korea, Taiwan, Switzerland, Liechtenstein, and European Union member countries, the combined additional Section 232 tariff and applicable Column 1 duty will equal 15%.

Covered products from the UK will face a 10% tariff.

The new tariffs will replace a narrower safeguard tariff on solar cells and modules that expired in February 2026.

Domestic Manufacturing Incentives

The proclamation authorizes the Commerce Secretary to establish a program encouraging U.S. production of raw polysilicon, ingots, wafers, and cells.

Companies can submit plans to build, refurbish, or expand U.S. manufacturing facilities for covered products. Approved plans must commit to beginning construction by January 20, 2029.

Companies with approved plans can import necessary manufacturing equipment and covered products without applicable Section 232 duties. Import volumes will depend on newly committed investment, with benefits tied to construction progress.

Commerce can withdraw benefits if a company substantially fails to meet its commitments. Benefits can be rescinded retroactively for fraud or deliberate misrepresentation.

US Polysilicon Manufacturing

The Commerce investigation found that the U.S. share of global polysilicon production capacity fell from 50% in 2005 to less than 2% in 2024. Its share of global semiconductor wafer fabrication capacity declined from 37% in 1990 to 10% in 2024.

The U.S. was also almost entirely dependent on imports of solar ingots, wafers, and cells.

Global polysilicon production increased by more than 270% from 2020, while inventories reached a record 400,000 tons by the end of 2024, according to the proclamation.

Semiconductor-grade polysilicon accounted for 2.4% of global polysilicon production. The proclamation said demand for solar-grade polysilicon supports production volumes and viable costs for both solar-grade and semiconductor-grade material.

The Commerce Secretary will continue to monitor polysilicon and derivative imports and can act with U.S. Customs and Border Protection if a company stockpiles covered products before December 4.

Meanwhile, the U.S. International Trade Commission has determined that imports of silicon metal from Australia and Norway have materially injured the domestic industry, paving the way for the imposition of antidumping and countervailing duties on the products. It reached final affirmative injury determinations after concluding that silicon metal from the two countries was sold in the U.S. at less than fair value and benefited from government subsidies.

This February, the U.S. Department of Commerce concluded that revoking the prevailing antidumping and countervailing duties on crystalline silicon photovoltaic product imports from China and Taiwan would lead to a recurrence of dumping.

In the same month, the U.S. announced its preliminary determination of countervailing duties of up to 125.87% on crystalline silicon solar cells, whether or not assembled into modules, imported from India.