Section 301 Tracker: USTR's 2025–2026 Investigation Wave

The most restless of the four authorities

If Section 232 is the slow-moving national-security layer, Section 301 is its opposite: an investigation-driven authority that produces new actions on a rolling basis rather than settling into a fixed schedule. Section 301 of the Trade Act of 1974 lets the US Trade Representative investigate foreign practices it considers unreasonable or discriminatory and respond with tariffs. The existing China program — four lists plus the 2024 statutory-review increases — is the well-known part. What makes 2025 and 2026 worth a dedicated tracker is the wave of new investigations USTR has opened on top of it, several of which name China but several of which reach well beyond it.

Brazil, July 2025

The first of the recent actions targeted Brazil. On July 15, 2025 USTR announced the initiation of a Section 301 investigation into Brazil, published in the Federal Register as document 2025-13498. The probe spans digital trade and electronic payment services, preferential tariffs, anti-corruption enforcement, intellectual property protection, ethanol market access, and a failure to enforce laws against illegal deforestation that USTR argues disadvantages US timber and agricultural producers. It is a reminder that Section 301 is not a China-only instrument, even though China remains its largest target.

The March 2026 double-header

The most consequential recent moves came within a day of each other in March 2026. On March 11, USTR initiated investigations into structural excess capacity across China and fifteen other economies, alleging that those economies produce far more than they can consume domestically and thereby displace US production. The named sectors are sweeping — aluminum, automobiles, batteries, semiconductors, ships, solar modules, steel, and a long list of others. Then on March 12, USTR initiated a separate set of 60 investigations into failures to enforce forced-labor import bans. Together they represent one of the broadest single openings of Section 301 activity on record.

How Korea got swept in

The Korea thread shows how these investigations can broaden in scope. A Section 301 petition from shareholders of the e-commerce platform Coupang prompted discussions with US trade officials in early 2026, but rather than pursuing a narrow company-specific complaint, those investors withdrew the petition after signals that Washington intended a wider look at Korean trade practices. Korea was ultimately folded into the sixteen-economy structural-excess-capacity investigation rather than made the subject of a standalone case. The lesson for importers is that the boundary of a Section 301 action is set by USTR, not by the original complainant, and can expand from a single firm to a whole economy.

The deadline that ties it together

These investigations are not yet tariffs, but USTR has signaled that it intends to conduct them on an expedited basis and to be positioned to impose any resulting duties around July 24, 2026. That date is not a coincidence: it is the same window as the Section 122 surcharge expiration, and it suggests an effort to have new Section 301 measures ready as the balance-of-payments surcharge potentially lapses. For importers, the practical implication is that the summer could bring a reshuffling of the tariff stack rather than a simple reduction — one layer expiring while another is prepared to take its place.

What an importer should actually do

The existing China rates have not gone away while the new investigations proceed: the four lists and the 2024 review increases — electric vehicles at 100%, solar at 50%, and the rest — remain in force and continue to stack on top of the base rate for Chinese-origin goods. The new actions add forward risk for goods from China and from the broader set of named economies. The sensible response is to treat Section 301 status as a moving figure for any affected sourcing country, check the specific list and HTS code that applies to your product, and revisit the assumption each quarter. The Section 301 explainer lays out the list structure and the replacement-rate logic, and the China country overview shows how the layers combine for the most exposed origin.

The 2024 review rates that are already locked in

Underneath the new investigations sits the body of Section 301 tariffs that are already final, and they remain the rates an importer of Chinese goods actually pays today. The 2024 statutory review — the four-year check the statute requires — reaffirmed the four original lists and layered targeted increases on sectors the United States treats as strategic. Electric vehicles were raised to 100%, solar cells and modules to 50%, and advanced semiconductors to 50%, while lithium-ion batteries for non-vehicle uses, critical minerals, and medical gloves were raised to 25%. Those increases were phased in across late 2024, the start of 2025, and the start of 2026 rather than imposed all at once. The 2025 and 2026 investigations do not displace any of this; they sit alongside the existing program as potential additions, which means a China importer should read the current rate and the investigation pipeline as two separate things to monitor.

Replacement rates versus stacking

One technical point repays close attention because it changes the arithmetic in a way that is easy to get wrong. The 2024 increase rates are replacement rates, not additive ones. A Chinese-origin electric vehicle faces a 100% Section 301 rate that replaces the prior 25% list rate — it does not owe 125%. The same substitution logic governs the solar and semiconductor increases. Treating a replacement rate as if it stacked on top of the base list rate inflates a landed-cost estimate dramatically and can kill a sourcing decision that would actually have been viable. Before adding any other layer to a Chinese-origin calculation, confirm whether the figure you are starting from is a base list rate or a 2024 replacement rate, because everything else in the stack builds on that foundation.