The December 4 solar tariff caps a short list of origins at a combined 15%: the EU, Japan, Korea, Taiwan, Switzerland and Liechtenstein. The United Kingdom sits at 10%. Outside that list, the tariff adds on top of whatever already applies, with no ceiling.
Türkiye is the case we can size precisely. The general Section 301 replacement rate (10–12.5%, effective July 24) stacks with the solar floor to roughly 25–27.5%. That base rate is itself contested in court: a private suit was filed the day it took effect, and a 25-state attorney general suit followed on August 3, with no ruling yet.
Malaysia, Vietnam, Thailand, India, Indonesia and every other non-listed origin also stack Section 232 on top of their own existing tariffs, and each stack is different. If your market-entry math treats “15% tariff” as one number that applies everywhere, it doesn't. It's worth checking your specific origin rather than assuming.
Sources
- Section 232 solar/polysilicon proclamation and legal analysis (White & Case).
- Section 301 replacement action, July 2026.
- U.S. District Court and state attorney general filings, July–August 2026.