The US Commerce Department can now bar companies from importing polysilicon if it finds they are stockpiling it before new tariffs start, under a temporary rule published on 24 September [1].
Polysilicon is the base material for semiconductors, and is also used to make solar products [1].
A presidential proclamation of 6 August set minimum import prices and tariffs on polysilicon and products made from it, from 4 December. The new rule covers the months in between [1].
Commerce says trade data from the week after the proclamation showed "dramatic increases in polysilicon imports from some" importers, compared with their usual weekly volumes [1].
What it covers
Every importer of record bringing polysilicon or its derivatives into the US before 4 December. The rule runs from 22 September to 3 December 2026 [1].
Commerce will compare each importer's volumes since 6 August with its weekly averages earlier in 2026 and in 2025. It will also look at the use of affiliates or new importers of record [1].
Importers judged to be stockpiling will be barred from further entries until 4 December, unless Commerce grants them a waiver. New importers registered on or after 6 August face separate limits [1].
The rule took effect without the usual public comment period. Commerce says a delay would have let importers keep stockpiling [1].
What it does not tell you
What the minimum prices and tariffs will be. They are set in the proclamation, not in this rule [1].
Which importers, if any, have been barred. The rule sets a process and names no companies [1].
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