Section 301 Line Exposure: Mapping 7,045 Taxed Lines Across the Schedule

Updated October 2026. Every figure below is recomputed from our structured extract of the Chapter 99 trade-action schedule and cross-checked against the USITC REST API on October 13, 2026; 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 roughly 11,400 eight-digit lines in the US Harmonized Tariff Schedule, exactly which ones carry the Section 301 action today, where do they cluster, and what sits underneath them?

The answer: 7,045 unique eight-digit HTSUS lines carry one of the three 25 percent China actions, spread across 81 of the schedule's 96 substantive chapters. One number describes the whole map - the action adds 25 percent everywhere - but the map itself is anything but uniform. Chemicals dominate. Machinery follows. And fifteen chapters, including the entire apparel-and-footwear complex, are nowhere in it.

One action rate, three legal anchors

All 7,045 lines share the same incremental rate - 25 percent - but they attach through three separate chapter 99 provisions, each with its own legal enumeration:

We verified the correspondence against the live USITC REST export on 2026-10-13: heading 9903.88.01 covers articles as provided for in U.S. note 20(b), 9903.88.02 enumerates note 20(c) and 20(d), and 9903.88.03 enumerates note 20(e) and 20(f). Each provision sets out the operative economics in one sentence: “The duty provided in the applicable subheading plus 25%.” In trade terms these three provisions correspond to the actions popularly known as List 1 ($34 billion, effective July 6, 2018), List 2 ($16 billion, effective August 23, 2018) and List 3 (effective September 24, 2018 at 10 percent, raised to 25 percent on May 10, 2019).

The chapter density map

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

The four most exposed chapters alone hold 29.5 percent of all taxed lines; the top eight hold 42.6 percent. A chemicals buyer in chapter 29 faces denser coverage than any other sector - 692 distinct eight-digit lines - not because chemicals are politically sensitive but because chapter 29 is simply enormous: hundreds of discrete commodity codes, almost all industrially sourced from China at the time the actions were designed. Density, not value, is what the map measures, and that is precisely what makes it useful for screening: your eight-digit code either appears once in the enumeration or it does not.

Chapter 03 (fish) ranking fourth catches many importers off guard until they remember frozen and processed seafood flows through hundreds of granular statistical lines. Chapter 87 (vehicles and parts, 188 lines) and chapter 90 (instruments, 215 lines) round out the industrial core of the action.

The fifteen zero-exposure chapters

Just as instructive is where the map is empty. Fifteen chapters carry zero lines under the three 25 percent actions: 01 (live animals), 06 (living trees), 09 (coffee, tea, spices), 13 (lac, gums), 18 (cocoa), 49 (printed books), 61, 62 and 63 (knitted and woven apparel, home textiles), 64 (footwear), 66 (umbrellas), 92 (musical instruments), 93 (arms), 95 (toys and games) and 97 (works of art).

This is not an accident of the data. When Washington escalated to the fourth list in 2019, the finished consumer complex - apparel, footwear, toys - was deliberately routed into List 4A at 15 percent, later reduced to 7.5 percent from February 14, 2020, rather than the 25 percent tier. Those 7.5 percent lines live in different chapter 99 provisions and are outside this map; treating them as 25 percent exposure would overstate your landed cost. The practical rule: absence from the 25 percent lists is not absence from Section 301.

What sits underneath: the base-rate census

Because the action rate stacks on the base rate, the true burden of a line equals base + 25 points. Joining all 7,045 taxed lines back to the full schedule gives the distribution of what importers actually pay beneath the action:

• 2,858 lines (40.6%) have a Free base rate - their total is exactly the 25 percent action rate. Examples: freshwater ornamental fish (0301.11.00), ethane and n-pentane (2901.10.10, 2901.10.30).
• 3,731 lines (53.0%) have an ad valorem base with a median of 5.0 percent and a mean of 6.4 percent - typical totals run 27 to 35 percent. Example: boiler parts 8402.90.00 at 4.3% base becomes 29.3% all-in.
• 456 lines (6.5%) 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 25 percent applies to value on top of the per-unit component.

The Free-heavy shape matters commercially: for four lines in ten, quoting the China landed cost means adding a flat 25 points and nothing else. For the majority, however, the classic classification error is to quote the 25 percent 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 any chapter 99 actions that touch it.
2. Check the neighborhood. 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. Compute the stack. Add 25 points to the base - or to the value leg if your base is specific or compound.
4. Date-stamp the result. Coverage changes through exclusions and periodic reviews; our underlying extract was captured from the USITC Chapter 99 file on October 12, 2026 (SHA-256 recorded), 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: 7,045 records, one per unique eight-digit HTSUS line, each carrying its action heading, basis note, 25.0 percent rate, source URL (hts.usitc.gov, Chapter 99 release file) and retrieval timestamp 2026-10-12T16:13:42Z. The build parsed 62 chapter 99 anchors covering the note 20 subchapter and retained the three 25 percent enumerations analyzed here; other scopes (7.5 percent List 4A lines among them) are tracked separately. 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.