A proclamation signed on Thursday puts a floor price under imported polysilicon, and an importer whose documentation is materially inaccurate is barred from the product permanently

$21 a kilogram.

That is the floor the United States will put under imported polysilicon, and it is the smallest of four. Polysilicon ingots and wafers carry a minimum import price of $100 a kilogram. Solar cells carry $0.22 a watt and modules $0.38 a watt. All four bite on goods entered for consumption, or withdrawn from warehouse for consumption, on or after 12:01 a.m. Eastern on 4 December, and a separate duty of 15 percent ad valorem starts the same morning on polysilicon ingots and on the derivative products listed in the two annexes.

The floor is enforced through paperwork, not through a rate

A price floor at a border needs somebody to prove the price, and the proclamation puts that on the importer at the moment of entry. Customs and Border Protection is to accept documentation certifying that the first arm's length sale of the goods in the United States, or of any downstream product made from them, will happen at or above the applicable minimum. A contract on fixed terms signed before Thursday qualifies instead.

Miss the filing and the consequence is not a percentage. An importer who submits nothing pays a specific duty equal to the whole minimum import price. An importer who files and then enters the goods below the floor pays the difference between the entered value and the floor.

The penalty for getting the certification wrong is permanent

Clause 3 is the sentence to read twice.

If Customs determines that an importer's documentation was materially inaccurate, or that the importer materially failed to comply with its certification, that importer and its affiliates are permanently prohibited from importing polysilicon and polysilicon derivatives into the United States. Penalties may follow on top. The proclamation attaches no cure period, no appeal and no expiry to that prohibition.

Fifteen percent, with a ceiling for six trading partners and a lower rate for one

The new duty applies in addition to everything else, with exceptions written into the text. For products of Japan, Korea, Taiwan, Switzerland, Liechtenstein or a member nation of the European Union, the Section 232 tariff and the ordinary Column 1 rate must add up to 15 percent, so the ordinary rate is absorbed rather than stacked. For products of the United Kingdom the rate is 10 percent.

Manufacturing drawback survives, narrowly. It is available only where the article is not of a type subject to an antidumping or countervailing duty order, is a product of a listed trade agreement partner, and is made entirely of polysilicon from one of those partners.

Goods caught by the duties may enter a foreign trade zone only in privileged foreign status from the effective date, unless they qualify for domestic status. That fixes the duty at the door of the zone rather than at the door out of it.

Four months, and a clause about what happens inside them

An effective date in December on a proclamation signed in August leaves a window, and the document addresses it in one line. If the Secretary of Commerce determines that a company is stockpiling polysilicon or derivatives before the effective date, the Secretary is to act with Customs to restrict imports by that company and its affiliates.

The same clause structure offers the other direction. Commerce may accept and approve onshoring plans from companies committing to build, refurbish or expand American production of polysilicon, ingots, wafers or cells, provided construction starts by 20 January 2029. An approved company may import production equipment and covered products free of these duties during the construction period, in volumes Commerce judges commensurate with the investment, and the benefit may vary depending on whether those imports use American polysilicon.

The findings underneath

The Secretary's report, which the proclamation says was transmitted within the past 90 days, found that the American share of global polysilicon production capacity fell from 50 percent in 2005 to less than 2 percent in 2024. Global polysilicon production has grown by more than 270 percent since 2020, and inventories reached a record 400,000 tons by the end of 2024. The American share of global semiconductor wafer fabrication capacity fell from 37 percent in 1990 to 10 percent in 2024.

One finding explains why a semiconductor argument produced a solar remedy. Semiconductor grade polysilicon is now 2.4 percent of global polysilicon output, so the volumes that hold unit costs down come almost entirely from the lower purity solar grade. On the Secretary's reasoning, a domestic polysilicon industry cannot survive on the semiconductor slice alone.

The proclamation also says what it is replacing. The safeguard tariff on solar cells and modules imposed in the President's first term expired in February 2026, and these duties are described in the text as the broader successor to it.