Section 301 Tariffs Are Back: What Every Importer Needs to Know in 2026
After the Supreme Court struck down Trump's IEEPA reciprocal tariffs in early 2026, the trade war didn't end — it shifted gears. On March 11-13, 2026, USTR Jamieson Greer announced Section 301 trade investigations targeting over 60 countries, including China, the EU, Mexico, and more. If you import goods into the United States, this is the most important tariff development since April 2025.
This guide explains exactly what Section 301 tariffs are, how they differ from the now-struck-down IEEPA tariffs, what the new investigations mean for your supply chain, and what you should be doing today.
What Is Section 301 of the Trade Act of 1974?
Section 301 is a provision of the Trade Act of 1974 that gives the United States Trade Representative (USTR) broad authority to investigate and respond to foreign trade practices that are unfair, unreasonable, or discriminatory — and that burden or restrict U.S. commerce.
Unlike the IEEPA (International Emergency Economic Powers Act), which the Supreme Court ruled cannot be used to impose tariffs without explicit congressional authorization, Section 301 has a 44-year track record of surviving legal challenges. It's been used over 3,600 times. Courts consistently uphold it. This is why the Trump administration is turning to it now.
When the USTR finds that a country's trade practices are unfair, Section 301 authorizes tariffs, fees, or other trade restrictions — without needing additional congressional approval.
You've seen Section 301 tariffs before. The China tariffs from Trump's first term (2018-2019) — 25% on hundreds of billions of dollars of Chinese goods — were imposed under Section 301. Those tariffs survived Biden's entire term and are still in effect today.
Why Is This Happening Now? The IEEPA Tariff Backstory
To understand why Section 301 is back in the spotlight, you need to understand what just happened with IEEPA tariffs.
In April 2025, the Trump administration imposed sweeping "reciprocal tariffs" on most U.S. trading partners using the International Emergency Economic Powers Act — a national security law that the administration argued gave the president emergency economic powers. These tariffs ranged from 10% to 50%+ on imports from dozens of countries.
In early 2026, the Supreme Court ruled that IEEPA cannot be used to impose tariffs of this scope. The court found that the Act was meant for targeted sanctions and asset freezes, not broad-based import duties. The ruling entitled importers to $166 billion in refunds on tariffs paid since April 2025.
But — and this is the critical point for importers — the administration didn't accept defeat. Instead, it:
- Imposed a new 10% global tariff under Section 122 of the Trade Act (a short-term emergency provision), in effect through July 24, 2026
- Launched Section 301 investigations to rebuild tariff pressure through a legally durable mechanism
- Maintained existing China Section 301 tariffs from Trump's first term
The trade war continues. It's just moved to a stronger legal foundation.
The New Section 301 Investigations: What We Know
On March 11, 2026, USTR Greer announced Section 301 investigations targeting countries with alleged "structural excess capacity" — essentially, overproduction of goods that distorts global markets and disadvantages American industry.
Countries targeted include: - China (existing 301 tariffs; new probe on forced labor practices) - European Union (Germany, Ireland, France cited for trade surpluses) - Mexico - Singapore - Norway - Switzerland - 50+ additional economies
On March 13, 2026, a second round of probes was announced specifically targeting countries with forced labor trade practices — a separate legal hook under Section 301 that focuses on worker rights violations.
Timeline: Section 301 investigations typically take 6-12 months before tariffs are imposed. The USTR holds public comment periods, conducts hearings, and publishes final determinations. This means new 301 tariffs are unlikely before late 2026 or early 2027 — but the direction is clear.
What tariff rates are possible? In Trump's first term, Section 301 tariffs on China started at 25% on specific product categories. Rates can be product-specific or blanket. The administration has signaled it wants to replicate or exceed the IEEPA tariff levels through this mechanism.
How Section 301 Tariffs Affect Your Landed Cost
If you're importing goods — especially from China, but increasingly from other countries — you're already navigating a complex tariff stack. Here's what your total duty burden may look like under various scenarios:
Current Tariff Stack (as of March 13, 2026)
Goods from China: - Base MFN duty rate: 0-20% (product-specific, per HTS code) - Section 301 tariffs (List 1-4A/4B from Trump 1.0): 7.5%-25% - Section 122 global tariff (new, through July 24, 2026): 10% - Effective total: 17.5% to 55%+ depending on product
Goods from Mexico (USMCA-compliant): - Base MFN: 0% (duty-free under USMCA) - Section 122 global tariff: 10% (applies even to USMCA goods; exemptions narrow) - Effective total: ~10%
Goods from EU countries: - Base MFN: varies (avg ~3.5%) - Section 122 global tariff: 10% - Effective total: ~13.5%
Future risk (post-Section 301 investigations): - EU goods: potential 20-30% Section 301 tariffs if investigations find unfair practices - Chinese goods: potential additional 10-25% on top of existing rates
Understanding your exact HTS code — and which tariff lists apply — is the only way to calculate your true landed cost. General estimates are not sufficient for pricing decisions.
What Importers Should Do Right Now
1. Classify Your Products Correctly
HTS code accuracy has never mattered more. The difference between two closely related HTS codes can be 0% versus 25% in tariffs. If you haven't had a professional classification review in the last 12 months, do it now.
Common classification errors we see: - Misclassifying electronics components (HTS Chapter 84 vs 85) - Incorrect classification of composite products - Missing country-of-origin rules that affect which tariffs apply - Not claiming first sale valuation when available
2. Audit Your China Exposure
If any portion of your supply chain passes through China — even for components or processing — you need to quantify your Section 301 exposure. This includes:
- Direct imports from Chinese manufacturers
- Goods manufactured in third countries using Chinese components above the substantial transformation threshold
- Products that have historically been on Section 301 exclusion lists (many exclusions have expired)
3. Model Alternative Sourcing Now — Before 301 Tariffs Hit
The 6-12 month investigation timeline gives you a window. Use it. Countries currently not targeted by Section 301 investigations — Vietnam, India, Bangladesh, Cambodia — may offer duty advantages. But run the numbers including:
- Manufacturing cost differentials
- Quality and reliability risks
- Shipping costs and transit times
- Section 301 risk for each alternative country
A tariff calculator that includes all current rates across multiple countries can do this analysis in seconds.
4. File for Tariff Refunds If You Qualify
The $166 billion refund ruling covers importers whose entries were subject to IEEPA tariffs. The US Customs agency (CBP) has said a refund processing system will be ready within 45 days (as of March 6, 2026).
If you paid tariffs on imports from April 2025 through the court ruling date, you may be entitled to a refund. Work with a customs broker to identify eligible entries. File before any deadlines CBP announces.
5. Participate in Section 301 Comment Periods
Section 301 investigations include public comment periods where businesses can submit evidence on the economic impact of proposed tariffs. If your business would be significantly harmed by tariffs on a specific country or product category, submitting a comment can influence both the scope and rate of final tariffs.
Monitor USTR.gov for Federal Register notices on these new investigations.
6. Consider Bonded Warehouses and FTZs
If you're importing goods that may face future tariff increases, Foreign Trade Zones (FTZs) and bonded warehouses offer options to delay tariff payment until goods enter US commerce. This provides cash flow advantages and flexibility to sell or re-export goods if tariff economics change.
Section 301 vs IEEPA: Key Differences for Importers
| Section 301 | IEEPA | |
|---|---|---|
| Legal status | Supreme Court-proven | Struck down for tariffs |
| Implementation time | 6-18 months | Immediate |
| Product specificity | Targeted by product/HTS code | Broad-based |
| Appeal mechanism | Comment periods, exclusion requests | Emergency orders, less predictable |
| Refund eligibility | No (if upheld) | Yes (pending CBP system) |
| Historical precedent | China tariffs 2018-present | Novel use, legally fragile |
The shift to Section 301 means tariffs will be slower to arrive but harder to challenge. The legal foundation is much stronger. Once Section 301 tariffs are in place after a full investigation, importers have limited recourse beyond product exclusion requests.
How to Monitor These Developments
Tariff policy is moving fast in 2026. The March 11-13 Section 301 announcements are just the opening moves. Over the coming months, watch for:
- Public comment notices in the Federal Register for each country/investigation
- USTR hearing dates where businesses can testify
- Preliminary tariff lists identifying specific HTS codes targeted
- Presidential action extending or modifying the Section 122 10% global tariff (set to expire July 24, 2026)
- Retaliation announcements from EU, China, and Mexico
The Trade Updates page on TariffsCost pulls live data from the Federal Register and US Treasury, updated hourly. It's the fastest way to stay current without monitoring government sites manually.
Bottom Line for Importers
The Supreme Court may have struck down the IEEPA tariffs, but the trade war hasn't ended — it's just shifted to a more legally durable weapon. Section 301 investigations against 60+ countries signal that the administration intends to rebuild tariff pressure on a foundation that can survive judicial review.
The window between now and when Section 301 tariffs take effect is your opportunity. Use it to: - Audit your HTS classifications - Model alternative sourcing - File for IEEPA refunds you're owed - Build financial models that stress-test your margins under multiple tariff scenarios
If you're importing from any of the 60 countries now under investigation, the question isn't whether tariffs will affect you — it's how much and how soon. Run the numbers today.
Use the TariffsCost calculator to instantly see your landed cost under current and projected tariff scenarios. Enter your product, select your sourcing countries, and get a side-by-side comparison in seconds.