As of the verification date above, U.S. import tariffs are governed by three primary legal authorities. Section 301 applies tariffs based on countries and unfair trade practices, Section 232 applies tariffs to specific products and industries for national security reasons, and a temporary Section 122 surcharge replaced the now-invalid IEEPA tariffs following the U.S. Supreme Court’s February 2026 ruling. Importers who paid qualifying IEEPA tariffs may also be eligible for refunds through U.S. Customs and Border Protection (CBP), while Section 301 and Section 232 duties remain in effect and are not refundable under that ruling.

Understanding which tariff authority applies to your shipment is critical because multiple tariff programs can affect a single import entry. This guide explains how each authority works, when tariffs stack, which duties are refundable, and how importers can determine the total duty owed on a shipment.

The 2026 US Tariff System Runs on Three Legal Authorities

Today’s U.S. tariff system is built around three separate legal authorities, each designed for a different purpose. Rather than applying one universal import tariff, CBP determines which programs apply based on the product, country of origin, and current trade measures.

The three active authorities are:

Prior to February 2026, many importers also paid tariffs imposed under the International Emergency Economic Powers Act (IEEPA). Those tariffs are no longer being collected after the Supreme Court ruled that the administration exceeded its authority under IEEPA, fundamentally changing the structure of U.S. import tariffs.

The Supreme Court Ended IEEPA Tariffs and Opened a Refund Pool

One of the most significant customs developments of 2026 occurred on February 20, 2026, when the U.S. Supreme Court ruled in Learning Resources v. United States that the reciprocal and fentanyl-related tariffs imposed under IEEPA were unlawful.

As a result:

• IEEPA tariffs are no longer collected.
• Eligible importers may claim refunds for qualifying IEEPA duties paid between early 2025 and February 24, 2026.
• Refunds are being processed by CBP through its Consolidated Administration and Processing of Entries (CAPE) program within ACE.
• Section 301, Section 232, and Anti-Dumping and Countervailing Duties (AD/CVD) remain fully in force and are not affected by the Supreme Court ruling.

For many businesses, this distinction is critical. Receiving an IEEPA refund does not eliminate other tariff obligations that continue to apply to the same shipment.

Section 301 Targets Countries and Unfair Trade Practices

Section 301 is one of the most widely used tariff authorities affecting U.S. imports today.

Established under the Trade Act of 1974, it authorizes the United States Trade Representative (USTR) to impose tariffs on countries that engage in unfair trade practices or policies that disadvantage U.S. businesses.

Unlike Section 232, which focuses on products and industries, Section 301 primarily targets countries and specific trade practices.

The best-known Section 301 measures apply to imports from China, where many products remain subject to additional duties through HTSUS Chapter 99 classifications.

Current China measures generally include:

• Lists 1 through 3: 25% additional duty
• List 4A: 7.5% additional duty
• Elevated sector-specific duties introduced during the 2024 and 2025 review process for selected industries such as electric vehicles, semiconductors, batteries, and solar products.

Status Update: Proposed Forced Labor Section 301 Action

Status as of July 21, 2026

On June 2, 2026, USTR issued findings proposing new Section 301 duties of 10% or 12.5% on imports from dozens of investigated countries as part of a forced labor investigation.

At the time this article was verified, these duties remained proposed and had not been implemented. Importers should verify the latest USTR announcements before relying on these proposed measures for duty calculations.

Section 232 Targets Products, Not Countries

While Section 301 focuses on where goods come from, Section 232 focuses on what the goods are.

Created under the Trade Expansion Act of 1962, Section 232 allows the U.S. government to impose tariffs when imports are determined to threaten national security.

Rather than targeting specific countries, Section 232 applies to designated products and industries.

Current Section 232 measures include:

• Steel
• Aluminum
• Certain derivative steel and aluminum products
• Copper
• Automobiles and selected automotive products
• Additional sectors identified through presidential proclamations

Unlike temporary tariff authorities, Section 232 has no automatic expiration date. Each action remains in effect until it is modified or revoked through subsequent presidential action.

Recent adjustments have also introduced relief for certain USMCA-qualifying goods and derivative products meeting specified U.S.-content thresholds, demonstrating that Section 232 continues to evolve alongside broader U.S. trade policy.

Section 122 Was the Bridge After IEEPA

Following the Supreme Court’s decision invalidating IEEPA tariffs, the administration implemented a temporary surcharge under Section 122 of the Trade Act of 1974.

Section 122 permits the government to impose a temporary balance-of-payments surcharge while longer-term trade measures are considered.

Status as of July 21, 2026

• Effective date: February 24, 2026
• Surcharge: 10%
• Maximum duration permitted by statute: 150 days
• Scheduled expiration: July 24, 2026, unless Congress authorizes an extension.

Because Section 122 is temporary by law, importers should monitor CBP and USTR announcements closely. Proposed Section 301 actions may replace portions of this temporary surcharge, but no final replacement had been announced as of the verification date.

Trade Agreements Can Override the Default Tariff Layers

Although Section 301, Section 232, and Section 122 form the core of the U.S. tariff system, they do not apply uniformly to every country.

Trade agreements and country-specific arrangements may modify or replace the default tariff structure.

For example:

• USMCA allows qualifying goods from Canada and Mexico to receive preferential tariff treatment where applicable.
• A new arrangement effective July 1, 2026 establishes an all-inclusive tariff ceiling for many EU-origin goods, while certain metals remain subject to Section 232 measures.

Because each agreement contains its own eligibility requirements and product coverage, importers should evaluate tariff treatment based on both the product’s classification and its country of origin before estimating landed costs.

Multiple Tariff Programs Can Apply to a Single Import

One of the biggest misconceptions among importers is that only one tariff applies to each shipment.

In reality, a single import may be subject to several different duty programs at the same time. U.S. Customs and Border Protection (CBP) first determines the product’s ordinary customs duty under the Harmonized Tariff Schedule of the United States (HTSUS). It then evaluates whether additional tariffs apply under authorities such as Section 301, Section 232, or Anti-Dumping and Countervailing Duties (AD/CVD).

This process is commonly referred to as tariff stacking because multiple duty layers may apply to the same imported product.

For example, an imported steel component from China could potentially be subject to:

• Ordinary customs duty
• Section 301 additional duties
• Section 232 steel tariffs
• Anti-Dumping Duty (if applicable)
• Countervailing Duty (if applicable)

Understanding which tariff programs apply is essential for accurately estimating landed costs and avoiding unexpected duty assessments.

Tariffs Are Declared Using HTSUS Chapter 99 Classifications

Additional tariffs are generally reported using Chapter 99 of the Harmonized Tariff Schedule.

Rather than replacing your normal product classification, Chapter 99 provisions are entered in addition to the standard HTSUS classification.

For example, an importer may declare:

• The product’s standard HTSUS classification
• The applicable Chapter 99 Section 301 provision
• Any applicable Section 232 Chapter 99 provision

CBP uses these additional tariff numbers to calculate the extra duties owed while maintaining the underlying product classification.

Because Chapter 99 provisions change regularly, importers should always verify that they are using the correct tariff numbers before filing an entry.

How Tariffs Are Calculated

Calculating import duties involves more than applying a single percentage.

CBP generally follows this process:

1. Classify the product using the correct HTSUS code.
2. Determine the product’s customs value.
3. Apply the ordinary customs duty.
4. Determine whether any additional tariff authorities apply.
5. Calculate any applicable Section 301, Section 232, or AD/CVD duties.
6. Assess any merchandise processing fees (MPF), harbor maintenance fees (HMF), or other applicable charges.

Because different tariff programs use different legal authorities, calculating the final landed cost often requires evaluating multiple regulations rather than a single tariff rate.

Example: How Tariff Stacking Works

Consider a U.S. importer purchasing steel fasteners manufactured in China.

The shipment may be subject to:

Although the exact percentages depend on the product’s HTSUS classification and current trade measures, this example illustrates why importers should never assume the ordinary duty rate represents the total import cost.

A customs broker or trade compliance specialist can help identify every applicable duty before goods are shipped.

Can Importers Claim Refunds?

Whether duties can be refunded depends on which legal authority imposed them.

Following the Supreme Court’s February 2026 decision, many importers became eligible to recover duties previously paid under IEEPA. However, that ruling did not affect tariffs imposed under other authorities.

As a general rule:

Eligible IEEPA refunds are processed through CBP’s Consolidated Administration and Processing of Entries (CAPE) system within the Automated Commercial Environment (ACE). Importers should review their historical entries to determine whether they qualify.

How Importers Can Stay Compliant

Because U.S. tariff policies continue to evolve, importers should review their customs compliance procedures regularly.

Some best practices include:

• Verify the correct HTSUS classification before importing.
• Confirm the product’s country of origin.
• Determine whether Section 301 or Section 232 measures apply.
• Monitor USTR and CBP announcements for policy updates.
• Maintain supporting documentation for origin and valuation.
• Review historical entries to identify potential refund opportunities.
• Work closely with a licensed customs broker or trade advisor.

A proactive compliance strategy can reduce unexpected costs, minimize customs delays, and help businesses respond quickly when tariff rules change.

Frequently Asked Questions

What are U.S. import tariffs?

U.S. import tariffs are duties imposed on imported goods by the federal government. They may consist of ordinary customs duties as well as additional tariffs imposed under authorities such as Section 301 or Section 232.

What is the difference between Section 301 and Section 232?

Section 301 addresses unfair foreign trade practices and generally targets imports from specific countries. Section 232 protects U.S. national security by applying tariffs to designated products and industries, regardless of country in many cases.

Are the IEEPA tariffs still in effect?

No. Following the U.S. Supreme Court’s February 2026 decision, the reciprocal and fentanyl-related IEEPA tariffs were invalidated and replaced temporarily by a Section 122 surcharge while the government evaluates longer-term trade measures.

Can multiple tariffs apply to one shipment?

Yes. A single shipment may be subject to ordinary customs duty, Section 301 duties, Section 232 duties, Anti-Dumping Duty, Countervailing Duty, and government processing fees, depending on the product and country of origin.

Can I get a refund on tariffs I’ve already paid?

Only certain duties are refundable. Importers may be eligible to recover qualifying IEEPA duties, but Section 301 and Section 232 tariffs generally remain payable unless another exclusion or legal remedy applies.

How do I know which tariffs apply to my product?

The applicable tariffs depend on your product’s HTSUS classification, country of origin, and any active trade measures. A licensed customs broker or trade compliance specialist can help determine the correct duty treatment before importation.

Final Thoughts

Understanding U.S. import tariffs has become more complex than simply looking up a duty rate in the Harmonized Tariff Schedule. Today’s importers must consider multiple legal authorities, including Section 301, Section 232, and temporary measures such as Section 122, while staying informed about ongoing trade policy changes.

The 2026 Supreme Court decision eliminated IEEPA tariffs and created refund opportunities for many businesses, but it did not affect the broader U.S. tariff framework. Most importers must still evaluate ordinary customs duties alongside any applicable additional tariffs, trade remedies, and government fees.

By correctly classifying products, monitoring changes to trade policy, and working with experienced customs professionals, businesses can better manage landed costs, remain compliant with CBP requirements, and avoid costly surprises at the border.