9903.91.05 Explained: Section 301 China Four-Year Review, 50% Duty

Key Points

• HTS code 9903.91.05 imposed an additional 50% duty on articles the product of China, covering 19 specific subheadings, effective for entries on or after January 1, 2025.
• The 50% rate stacks on top of every other applicable duty: the rate is the duty provided in the applicable subheading plus 50%.
• All 19 subheadings that were ever covered by this code had expiration dates falling between January 1, 2026 and February 24, 2026, and none remain in force as of October 13, 2026.
• Entries that were made while a subheading was active and that may have been liquidated incorrectly could be candidates for post-entry correction; confirm your specific situation with a licensed broker.
• This code is part of the Section 301 four-year review escalations that sit in the 9903.91/.92 series, distinct from the original List 1-4 codes under 9903.88.

On this page

1. What 9903.91.05 is and where it fits in Section 301
2. Products and HTS subheadings that were in scope
3. The 50% rate and how it stacks with other duties
4. Effective window and expiration of all covered subheadings
5. Interaction with other Section 301 tariff provisions
6. What importers should do
7. Key references

HTS code 9903.91.05 is a Chapter 99 overlay code created under the Section 301 four-year review process, applying an additional 50% duty to specified Chinese-origin goods. It was effective for entries on or after January 1, 2025, and covered 19 subheadings, all of which have since expired. As of October 13, 2026, zero subheadings remain in force under this code. Importers who made entries during the active window should verify their duty calculations against the exact subheading-level expiration dates listed below.

The links in this article go to the primary documents: the proclamations, Federal Register notices, and official tariff schedule pages themselves. Read the source.

What 9903.91.05 is and where it fits in Section 301

Section 301 of the Trade Act of 1974, administered by the Office of the United States Trade Representative, authorizes additional tariffs on goods from countries found to engage in unfair trade practices. The original China tariff actions created four product lists covered by codes in the 9903.88 series. After those actions had been in place for several years, a statutory four-year review process produced a new round of escalated rates coded in the 9903.91 and 9903.92 series.

Code 9903.91.05 sits within that four-year review escalation tier. Its official heading text in the HTSUS reads: "Effective with respect to entries on or after January 1, 2025, articles the product of China, as provided for in subdivision (f) of U.S. note 31 to this subchapter." The governing product list is defined by U.S. note 31(f) to Subchapter III of Chapter 99. To see the authoritative current text, consult the Harmonized Tariff Schedule on hts.usitc.gov.

Related codes in the same escalation series include 9903.91.04 (25% duty), 9903.91.03 (100% duty), and 9903.91.02 (also 50% duty, different product scope). Each code covers a different slice of the product universe.

Products and HTS subheadings that were in scope

The 19 subheadings covered by 9903.91.05 are concentrated in semiconductors, integrated circuits, and closely related materials. The full list, with the exact effective window for each, is:

Subheadings active January 1, 2025 through February 1, 2026

• 8541 2900 (diodes, other than photosensitive or light-emitting)
• 8541 2100 (diodes, other)
• 8541 5100 00 (photosensitive semiconductor devices, photovoltaic cells)
• 8541 4970 (light-emitting diodes, other)
• 8542 3900 (electronic integrated circuits, other)
• 2804 6100 00 (silicon, containing by weight not less than 99.99% of silicon)
• 8541 4995 00 (other light-emitting diodes)
• 8541 4910 (light-emitting diodes for backlighting)
• 8541 1000 (diodes, other than photosensitive or light-emitting diodes)
• 8542 3200 (metal oxide semiconductors)
• 3818 0000 (chemical elements doped for use in electronics, in the form of discs, wafers, etc.)
• 8542 9000 00 (parts of electronic integrated circuits)
• 8542 3100 (processors and controllers, electronic integrated circuits)
• 8541 5900 (other photosensitive semiconductor devices)
• 8541 4980 00 (other light-emitting diodes)
• 8541 3000 (thyristors, diacs and triacs)
• 8542 3300 01 (amplifiers)

Subheading active January 1, 2025 through January 1, 2026

• 4015 1210 (surgical gloves of vulcanized rubber)

Subheading active January 1, 2025 through February 24, 2026

• 8541 9000 00 (parts of diodes, transistors, and similar semiconductor devices)

Confirm the precise 8-digit or 10-digit classification for your goods against the current HTSUS and with your customs broker, because classification disputes can affect which window applies.

The 50% rate and how it stacks with other duties

The general column rate for 9903.91.05 is the duty provided in the applicable subheading plus 50%. That construction means CBP adds the 50% Section 301 additional duty on top of whatever the column 1 general rate is for the underlying Chapter 1-97 subheading.

Stacking works like this on the entry summary:

• Line 1: The Chapter 1-97 subheading (for example, 8542.31.00) with its normal MFN rate.
• Line 2: 9903.91.05 as a second line on the same entry, with the 50% additional rate applied to the same entered value.

If the goods were also subject to any underlying Section 301 List rate from the 9903.88 series (for example, 25% under List 4), that rate would appear on a third line. The total duty burden for an affected entry during the active window could therefore be the MFN rate, plus any pre-existing Section 301 list rate, plus the 50% escalation under 9903.91.05. If you are reviewing past entries and want to check whether duty was computed correctly, see how to verify your broker's duty calculation on an entry summary.

Effective window and expiration of all covered subheadings

As of October 13, 2026, all 19 subheadings that were ever covered by 9903.91.05 have expired. No subheadings are currently in force under this code.

The expiration dates by group were:

• January 1, 2026: subheading 4015.1210 (surgical gloves)
• February 1, 2026: 17 semiconductor and related subheadings (see full list above)
• February 24, 2026: subheading 8541.9000.00 (parts of semiconductor devices)

An entry made on or after January 1, 2025 and before the applicable subheading's expiration date was subject to the 50% additional duty. An entry made on or after the expiration date for that subheading was not subject to 9903.91.05 for that good. If your entry date is near one of those boundaries, verify the exact entry date on your CBP Form 7501 and confirm the applicable window.

Interaction with other Section 301 tariff provisions

The 9903.91.05 escalation was designed to sit on top of, not replace, existing Section 301 list duties. Goods that were already subject to additional duties under the 9903.88 series continued to carry those duties; 9903.91.05 added another layer.

Other four-year review codes in the 9903.91 series cover different products and different rates. If your goods expired out of 9903.91.05 coverage, they may still carry duties under other codes in the series or under the original List codes. Check the current HTSUS Chapter 99 notes and all applicable 9903 codes for your specific subheading.

For a broader map of 2026 tariff code changes, see the 2026 tariff code overview.

What importers should do

• Audit past entries from January 1, 2025 through February 24, 2026. For every entry covering a China-origin good in the 19 subheadings listed above, confirm that 9903.91.05 was applied for the correct date window and that the 50% rate was calculated on the correct entered value. Use your ACE entry summary data and cross-reference the exact entry date against the per-subheading expiration dates above.
• Check for over-payment or under-payment at the subheading level. Because different subheadings expired on different dates (January 1, February 1, or February 24, 2026), a single shipment covering multiple line items may have had mixed applicability. Confirm each line independently.
• Verify classification before assuming coverage. The 9903.91.05 product scope is defined by U.S. note 31(f) to Subchapter III of Chapter 99. If your goods sit near the boundary of a covered subheading, confirm the 10-digit classification against the current HTSUS and consult a licensed broker.
• Check for continuing duties under other codes. Expiration from 9903.91.05 does not mean the goods are duty-free from China. Verify whether the underlying Chapter 1-97 subheading carries duties under other Section 301 codes still in force, using the HTSUS and CBP guidance at cbp.gov.

Key references

• Harmonized Tariff Schedule of the United States (hts.usitc.gov): The authoritative text of 9903.91.05 and U.S. note 31(f) to Subchapter III of Chapter 99.
• U.S. Customs and Border Protection (cbp.gov): Entry processing guidance, CSMS messages on Section 301 implementation, and ACE filing instructions.
• Federal Register (federalregister.gov): Notices and rules from the Office of the United States Trade Representative implementing Section 301 four-year review actions and rate modifications.
• White House (whitehouse.gov): Presidential proclamations and executive orders affecting Section 301 tariff levels.
• 19 U.S.C. 2411, Trade Act of 1974, Section 301 (law.cornell.edu): The statutory authority under which Section 301 China actions are maintained.
• 9903.91.04 Explained: Section 301 China Four-Year Review, 25% Duty: Coverage of the 25% escalation code in the same series.
• 9903.91.03 Explained: Section 301 China Four-Year Review, 100% Duty: Coverage of the 100% escalation code in the same series.
• 9903.91.02 Explained: Section 301 Four-Year Review, 50% Duty: The companion 50% code covering a different product scope.
• How Do I Check Whether My Broker Calculated the Duty Correctly?: Step-by-step guidance for reviewing entry summary duty computations.