When someone quotes you "the duty rate," they usually mean the base column-1 general rate — the one printed next to the eight-digit HTS line. In 2026 that base rate is often the smallest layer of what you actually pay. Four things stack, and they stack in a specific order:
| Layer | What it is | 2026 figure |
|---|---|---|
| 1. Base duty | Column-1 general rate on your HTS line | 0%–~16%+ |
| 2. Section 122 | Balance-of-payments surcharge, all origins | 10% |
| 3. MPF | Merchandise Processing Fee, formal entries | 0.3464%* |
| 4. §301/§232 | Origin-specific trade-remedy overlay (Ch.99) | varies |
*MPF is 0.3464% of entered value, floored at $33.58 and capped at $651.50 per entry. FTA claims from most partners (including Korea) exempt it entirely.
Layer 1 — Base duty
The column-1 general rate for the goods of a country with normal trade relations. Some lines are Free (many electronics, cosmetics), some run to double digits (apparel). This is the rate that lives on the legal eight-digit line, and it's the only layer your HTS code directly controls. Getting the code right does the most work — it's the one number that decides the base and the FTA eligibility and whether a §301 footnote applies.
Layer 2 — The Section 122 surcharge (the big one right now)
Section 122 of the Trade Act of 1974 (19 U.S.C. §2132) authorizes a temporary balance-of-payments import surcharge of up to 15%, applied across the board regardless of origin. As of this data version it is being collected at 10% on entered value, on top of the base rate — but treat that figure as contested and point-in-time, not settled law (see the litigation note below). It is not origin-specific — an FTA does not exempt you from the surcharge the way it exempts the base rate.
The catch that makes it worth watching: the §122 authority carries a statutory 150-day limit before extension requires Congress. On the current invocation that puts a scheduled sunset around 2026-07-24 unless extended, with successor Section 301 investigations reportedly pending. That sunset is a dated lever — deferring a non-urgent entry past it could remove the entire 10% on a qualifying shipment — but the exact date turns on how the 150-day clock is counted and on the litigation below, so confirm it before you plan freight around it.
Layer 3 — The Merchandise Processing Fee (MPF)
A flat ad-valorem fee on formal entries: 0.3464% of entered value, with a floor of $33.58 and a ceiling of $651.50 per entry. On a $10,000 entry that's $34.64. On a $200,000 entry it's capped at $651.50 — the cap bites above roughly $188,000 of entered value. The important part for savings: a valid FTA claim from most partners, including KORUS, exempts the MPF entirely. Miss the claim and you pay it; make it and it's zero.
Layer 4 — The Section 301/232 overlay
These are the origin-specific trade remedies — Section 301 (China, mostly) and Section 232 (steel and aluminum). They live in Chapter 99 of the tariff schedule and attach to your product via a footnote on the base HTS line (for example, a note reading "See 9903.88.02" signals Section 301 exposure). They are additional duties, not a replacement, and whether they apply depends on both your HTS code and your country of origin. A Korean-origin electrical device may carry a footnote that only bites for Chinese origin — so the same code can be clean from Korea and exposed from China.
Worked example: $10,000 LED mask from Korea
Put it together on a real case — an LED light-therapy face mask classified at 8543.70.98 (base 2.6%), entered at $10,000 from South Korea:
| Scenario | Base | §122 (10%) | MPF | Total |
|---|---|---|---|---|
| No FTA claim | $260.00 | $1,000.00 | $34.64 | $1,294.64 |
| KORUS claim | $0.00 | $1,000.00 | $0.00 | $1,000.00 |
| KORUS, after §122 sunset | $0.00 | $0.00 | $0.00 | $0.00 |
Two levers, both worth real money on this one shipment: the KORUS claim removes the base duty and the MPF ($294.64 back), and the Section 122 sunset removes the surcharge ($1,000). Note the order of operations — the surcharge is computed on entered value, not on top of the base duty, so it doesn't compound. Each layer is a flat percentage of the same $10,000 base.