President Trump signed a proclamation on Aug. 6 imposing a 15% tariff on imports of polysilicon derivatives, the core raw material used in semiconductor manufacturing. The White House said the move addresses threats posed by such imports to U.S. national security.
The proclamation also establishes minimum import price floors: $21 per kilogram for polysilicon and $100 per kilogram for polysilicon ingots and wafers.
Effective Date and Investigation Background
The measure will take effect at 12:01 a.m. ET on Dec. 4. The U.S. Commerce Department opened a Section 232 investigation into polysilicon under the Trade Expansion Act last July.
Trump said polysilicon is a foundational material underpinning the security of U.S. semiconductor and solar power supply chains, and that the measure is intended to rebuild the domestic polysilicon industry. The proclamation casts polysilicon as a critical node in national-security-related supply chains, using tariffs as a policy lever to bring production back to American soil.