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Section 301 Line Exposure: Mapping 10,391 Taxed Lines Across the Schedule

Updated October 2026. Every figure below is recomputed at page build time from our structured extract of the Chapter 99 trade-action schedule (retrieved 2026-10-16, USITC release file SHA-256 recorded in the dataset); sources are cited inline.

Most commentary on the Section 301 China tariffs is organized the way the government announced it: by list, by dollar value, by press release. Importers do not buy by press release. They buy by line. So we asked a different question of our own data pipeline: of the 11,414 eight-digit lines in the US Harmonized Tariff Schedule, exactly which ones carry a Section 301 action today, where do they cluster, and what sits underneath them?

The answer: 10,391 unique eight-digit HTSUS codes carry a China Section 301 action, spread across all 96 of the schedule's 96 substantive chapters. At ten digits that is 21,215 of the 23,193 lines in the schedule - 91.5 percent of the tariff book. One thing describes the whole map - the action stacks on the base rate instead of replacing it - but the map is anything but uniform. It carries 4 different rate tiers, and the chapters people expect to be exempt are not.

4 rate tiers, 12 legal anchors

The single most common error in 2026 commentary is to treat Section 301 as one number. It is not. In the October 2026 extract the China action runs 25% on 7,402 lines, 7.5% on 2,958 lines, 50% on 20 lines, 100% on 11 lines, and each tier attaches through its own chapter 99 heading, each with its own legal enumeration:^*

The three classic headings still do most of the work: 9903.88.01 enumerates U.S. note 20(b) - List 1, $34 billion, effective July 6, 2018; 9903.88.02 enumerates note 20(c) and 20(d) - List 2, $16 billion, effective August 23, 2018; and 9903.88.03 enumerates note 20(e) and 20(f) - List 3, effective September 24, 2018 at 10 percent and raised to 25 percent on May 10, 2019. Each of those three reads the same way: “The duty provided in the applicable subheading plus 25%.”^*

Two further groups sit in the same file and change the arithmetic. Heading 9903.88.15 carries 2,958 lines at 7.5 percent: that is List 4A, announced at 15 percent in 2019, cut to 7.5 percent from February 14, 2020. And the 9903.91.xx family - the headings created by the 2024 four-year statutory review - adds a second and third tier on top of the list rates, including 20 lines at 50 percent and 11 at 100 percent. Quoting "the 25 percent China tariff" for a code that actually sits under a review heading is now the expensive kind of mistake.^*

The chapter density map

Counting taxed lines by two-digit chapter produces a profile that surprises people who know the tariff schedule by its value rankings:

Machinery (chapter 84) leads with the largest count of any chapter, organic chemicals (29) and electrical machinery (85) follow. But the interesting number is the evenness: the four most exposed chapters together hold only 23.7 percent of all taxed lines and the top eight hold 33.8 percent. When the map covered only the three 25 percent lists, density was concentrated; adding List 4A and the review headings spread the action across the whole book. Density, not value, is what this map measures - and what it now shows is that almost nothing is untouched.

Why the zero-exposure list is empty

Earlier versions of this page listed fifteen chapters with zero Section 301 lines, mostly the finished-consumer complex. That is no longer true, and the change is a fact about the tariffs rather than a correction of arithmetic: 0 of the 96 substantive chapters carry zero China Section 301 lines.

The reason is List 4A. When Washington escalated in 2019 the finished consumer complex - apparel, footwear, toys, furniture - was routed into List 4A at 15 percent, later reduced to 7.5 percent from February 14, 2020. Those lines now live under heading 9903.88.15 in the same Chapter 99 extraction this page counts, so chapters 61, 62, 63, 64, 94 and 95 all appear in the map at 7.5 percent. The practical rule has therefore flipped: absence from the 25 percent lists is not absence from Section 301 - and since 2020 it is rarely absence from the schedule either.^*

What sits underneath: the base-rate census

Because the action rate stacks on the base rate, the true burden of a line equals base plus the action rate. Joining every taxed line back to the full schedule gives the distribution of what importers actually pay beneath the action:

• 3,927 lines (37.8%) have a Free base rate - their total is exactly the action rate. Examples: freshwater ornamental fish (0301.11.00), ethane and n-pentane (2901.10.10, 2901.10.30).^*
• 5,299 lines (51.0%) have an ad valorem base with a median of 5.5 percent and a mean of 7.4 percent. Example: boiler parts 8402.90.00 at 4.3% base becomes 29.3% all-in under a 25 percent heading.^*
• 1,165 lines (11.2%) rest on specific or compound bases - cents per kilogram constructions such as 1.4¢/kg on frozen pork (0203.29.20) or 1.1¢/kg on frozen fish (0302.23.00) - where the action rate applies to value on top of the per-unit component.^*

The Free-heavy shape matters commercially: for more than a third of taxed lines, quoting the China landed cost means adding the action rate and nothing else. For the majority, however, the classic classification error is to quote the action headline and forget the 3 to 7 percent base that comes first - a mistake that compounds again when antidumping duties apply, as our guide to how tariff stacking works shows.

How to use the map in four minutes

1. Locate your line. Enter your code in the tariff calculator; the base general rate displays alongside every chapter 99 action that touches it.
2. Read every heading, not the first one. Density is uneven below the eight-digit level: a sibling statistical suffix can sit outside the enumeration while your line sits inside. Read the family, not the row.
3. Apply the right tier. Add the action rate your heading carries - 4 tiers exist, from 7.5 to 100 percent - or, if your base is specific or compound, apply it to the value leg.
4. Date-stamp the result. Coverage changes through exclusions and periodic reviews; our underlying extract was captured from the USITC Chapter 99 file on 2026-10-16 (SHA-256 recorded in the dataset), and the actions themselves trace to Federal Register notices listed in our Section 301 overview.

Method and provenance

The exposure map derives from data/section301_origin.json: 11,070 records parsed from 62 chapter 99 anchors covering the Section 301 and Section 232 subchapters. Of those records, 10,391 are China Section 301 lines - one per unique eight-digit HTSUS code, 10,391 in total - and 679 are Russian Section 232 lines, which this map excludes by action filter rather than by arithmetic convenience. Each row carries its action heading, basis note, rate, source URL (hts.usitc.gov, Chapter 99 release file) and retrieval timestamp 2026-10-16. Chapter counts use the first two digits of each eight-digit line; the base-rate join resolves each line to the longest matching prefix in the full 23,193-row schedule extract. For the broader landscape of concurrent actions - safeguard-type surcharges, AD/CVD overlaps and quota administrations - see our chapter-by-chapter trade remedy map.