9903.79.05 Semiconductors 232: The R&D Exemption Explained

Key Points

• HTS 9903.79.05 is an exemption heading, not a duty heading: it carries no additional duty of its own, and goods claimed under it pay only the rate in their underlying Chapter 1-97 subheading.
• The exemption applies to semiconductor articles, as defined in subdivision (b) of U.S. note 39, that are destined for research and development in the United States, as defined in subdivision (d) of U.S. note 39.
• The program sits under the Section 232 semiconductors framework; the duty-imposing heading for that program is 9903.79.01, while 9903.79.05 and its sibling headings (.02 through .09) are the exclusion and exception provisions.
• Claiming 9903.79.05 requires entering it as a second Chapter 99 line alongside the regular Chapter 1-97 classification on the CBP entry summary.
• The definitions in U.S. note 39 control who qualifies; confirm those definitions against the current HTSUS before filing.

On this page

1. What 9903.79.05 is and what it does
2. The Section 232 semiconductors program and its structure
3. Which goods qualify: semiconductor articles and the R&D requirement
4. Rate and duty stacking: what you actually pay
5. How 9903.79.05 appears on a CBP entry
6. Sibling exemption headings and how they compare
7. What importers should do
8. Key references

HTS 9903.79.05 is an exemption heading within the Section 232 semiconductors program. Importers who qualify under it are not subject to the Section 232 semiconductor duty on their shipments; they pay only whatever rate applies in the underlying Chapter 1-97 subheading. As of August 14, 2026, the heading covers semiconductor articles, as defined in subdivision (b) of U.S. note 39, that are imported for research and development in the United States, as defined in subdivision (d) of U.S. note 39. The links in this article go to the primary documents: the official tariff schedule, CBP guidance pages, and Federal Register notices themselves. Read the source.

What 9903.79.05 is and what it does

Chapter 99 of the Harmonized Tariff Schedule of the United States (HTSUS) is reserved for temporary and special-purpose provisions. Headings in the 9903.79.xx range belong to the Section 232 semiconductors program. Within that range, 9903.79.01 is the operative duty heading, meaning it is the provision that actually imposes additional Section 232 duties. Headings 9903.79.02 through 9903.79.09 are structured as exclusion and exception provisions under U.S. note 39 to the subchapter.

9903.79.05 falls squarely in that exclusion tier. Its official heading text reads: "Semiconductor articles, as defined in subdivision (b) of U.S. note 39 to this subchapter, that are for research and development in the United States, as defined in subdivision (d) of U.S. note 39 to this subchapter." The HTSUS general column rate for this heading is "the duty provided in the applicable subheading," which is the drafting convention used to signal that no additional duty is layered on by this heading itself.

The Section 232 semiconductors program and its structure

Section 232 of the Trade Expansion Act authorizes the executive branch to impose tariffs or other trade restrictions when an investigation finds that imports of a particular product threaten national security. The semiconductors program under Section 232 applies that authority to a defined universe of semiconductor articles. The duty-imposing mechanism lives at 9903.79.01. Importers who cannot claim any exclusion or exception heading must report 9903.79.01 and pay the additional duty it carries.

U.S. note 39 to the subchapter is the legal framework that ties the program together. Its subdivisions define, among other things, what counts as a "semiconductor article" (subdivision (b)) and what qualifies as "research and development in the United States" (subdivision (d)). Every eligibility question for 9903.79.05 runs through those definitions. You can find the current text of U.S. note 39 in the official HTSUS at hts.usitc.gov. For broader context on how the Section 232 semiconductors action fits alongside other recent Section 232 expansions, see our article on Section 232 expanding to copper and related actions.

Which goods qualify: semiconductor articles and the R&D requirement

Semiconductor articles (subdivision (b))

Not every product that contains a chip is a "semiconductor article" for this program. Subdivision (b) of U.S. note 39 supplies the controlling definition. Importers and brokers must map their goods against that text, not against a general industry understanding of the term. Confirm the current subdivision (b) language in the HTSUS before classifying any shipment under 9903.79.05.

Research and development in the United States (subdivision (d))

The R&D requirement is the second gate. Subdivision (d) of U.S. note 39 defines what qualifies as research and development in the United States for purposes of this exemption. The definition controls: internal company usage of the phrase is not sufficient. Importers claiming 9903.79.05 should document, at the time of entry, how their intended use meets subdivision (d)'s criteria. If goods imported under this exemption are diverted to non-qualifying uses after entry, that diversion may create duty liability and could implicate CBP's subsequent-use rules.

Rate and duty stacking: what you actually pay

When 9903.79.05 is properly claimed, the Section 232 semiconductor duty that would otherwise apply through 9903.79.01 does not attach. The importer pays only the rate found in the underlying Chapter 1-97 subheading, that is, the normal column 1 general rate for goods from most trading partners, or the applicable column 2 or preferential rate depending on origin.

Other duties are not displaced by this exemption. Antidumping duties, countervailing duties, Section 301 tariffs, or any other applicable Chapter 99 provision may still stack on top of the Chapter 1-97 rate. 9903.79.05 speaks only to the Section 232 semiconductor duty; it says nothing about those other programs. Verify the full duty picture for your specific product and country of origin before finalizing landed-cost calculations. Our duty calculator can help you model stacking scenarios.

How 9903.79.05 appears on a CBP entry

Chapter 99 codes are reported as additional classification lines on CBP entry summaries; they ride alongside, not instead of, the regular Chapter 1-97 line. A typical entry for goods claimed under 9903.79.05 will show two classification lines for the affected merchandise:

• Line 1: The Chapter 1-97 subheading that describes what the product actually is, with the applicable rate.
• Line 2: 9903.79.05, with the rate "the duty provided in the applicable subheading," signaling to CBP that the importer is claiming the R&D exemption and that no Section 232 semiconductor duty applies.

CBP's Automated Broker Interface and ACE system expect this dual-line structure. Omitting 9903.79.05 from a qualifying entry means the system will look for the duty heading 9903.79.01 and assess Section 232 duties. Conversely, claiming 9903.79.05 on a shipment that does not satisfy the U.S. note 39 definitions is a classification error that can trigger penalties and back-duties. Check cbp.gov for any current CSMS messages addressing entry requirements for this program.

Sibling exemption headings and how they compare

9903.79.05 is one of several exception and exclusion headings under U.S. note 39. Importers should confirm they are using the correct heading for their specific situation:

• 9903.79.02 covers a separate exclusion category. See our article 9903.79.02 Semiconductors 232: What This Exclusion Heading Means.
• 9903.79.03 is the data center semiconductor exemption. See 9903.79.03: Data Center Semiconductor Exemption Explained.
• 9903.79.04 covers repairs and replacements. See 9903.79.04 Semiconductors 232: The Repairs and Replacement Exemption.
• 9903.79.06 through 9903.79.09 cover additional categories defined in U.S. note 39. Confirm which heading fits your goods against the current HTSUS.

Using the wrong sibling heading, or stacking more than one when only one applies, are common filing errors in new Section 232 programs. When in doubt, confirm current HTSUS text and any CBP guidance before filing.

What importers should do

• Pull the current text of U.S. note 39, subdivisions (b) and (d), from hts.usitc.gov and map your specific semiconductor articles and intended U.S. use against both definitions before claiming 9903.79.05.
• Instruct your customs broker to report 9903.79.05 as a second Chapter 99 line on the entry summary alongside the Chapter 1-97 classification, and verify that 9903.79.01 is not also being reported for the same line.
• Document the R&D end-use at the time of importation, and maintain records sufficient to demonstrate compliance with subdivision (d) in the event of a CBP inquiry or post-entry audit.
• Check cbp.gov for any CSMS messages and the Federal Register for any amendments or clarifications to the Section 232 semiconductors program that may affect eligibility or entry procedures.

Key references

• HTSUS at hts.usitc.gov: Official text of heading 9903.79.05 and U.S. note 39, including subdivisions (b) and (d).
• CBP at cbp.gov: Entry guidance, CSMS messages, and ACE filing requirements for Chapter 99 Section 232 provisions.
• Federal Register at federalregister.gov: Notices and rules establishing and amending the Section 232 semiconductors program.
• White House at whitehouse.gov: Presidential proclamations authorizing Section 232 semiconductor actions.
• 19 U.S.C. 1862 (Trade Expansion Act, Section 232): The statutory authority for the semiconductors program.
• 9903.79.02 Semiconductors 232: What This Exclusion Heading Means: Companion article on the .02 sibling heading.
• 9903.79.03: Data Center Semiconductor Exemption Explained: Companion article on the data center exemption.
• 9903.79.04 Semiconductors 232: The Repairs and Replacement Exemption: Companion article on the repairs and replacement exemption.
• Section 232 Expands to Copper; UK Pharma Tariffs Drop to Zero: Context on recent Section 232 program expansions.
• 2026 Tariff Code Overview: Broad reference for Chapter 99 codes in effect in 2026.