Duty Stack Forecast: Model Section 232 Raises and Section 301 Tier Changes Before They Hit

Tariff volatility in 2026 is a planning problem, not a compliance problem. Section 232 rates doubled between March and June 2025. Section 122 proclaimed and reproclaimed multiple times in the first half of 2026. Section 338 Canada surcharge hit in August. Every one of these actions was foreseeable 30 to 90 days out from the ambient political signal, but almost no importer had a pre-computed portfolio impact ready to guide procurement decisions when the proclamation dropped.

Duty stack forecast is the tool that closes that gap. Model pending tariff actions on your entry portfolio 60 to 180 days out. Compare scenarios side by side. Rank supplier switches, inventory pre-builds, and FTZ moves by portfolio-level duty avoidance. Open the forecast at landedfees.com/forecast.

Why forecasting matters more than reactive compliance

Reactive compliance is fine when tariff changes are gradual. It becomes expensive when they are step-function. A 25-to-50 percent Section 232 raise on aluminum triggered overnight in June 2025 caught importers with 60-day inventory pipelines mid-flight and no time to renegotiate supplier contracts or shift origin.

Forecasting compresses the response window. If procurement knows 45 days out that the raise is probable, they can:

• Accelerate in-transit inventory to land before the effective date.
• Sign short-term contracts with alternate-origin suppliers as a hedge.
• Move covered inventory into FTZ under 19 CFR 146 to defer the duty impact.
• Draft PSC filings for entries that would benefit from a producer affidavit on 232 derivative value splits before the higher rate hits.

Each of those actions has a cost. The forecast provides the dollar-value comparison so procurement can choose between them on evidence.

The tariff actions the forecast models

The forecast engine tracks and models these pending actions:

Section 232 rate changes. The March 2025 steel raise (25 to 50 percent) and the June 2025 aluminum raise (25 to 50 percent) established that Section 232 rates can double via proclamation. Copper 232 has been discussed for late 2026. The forecast models each pending rate scenario against the portfolio's Section 232-exposed entries.

Section 301 tier changes. List 4A exclusions expiration cycle, forced-labor tier expansion at 9903.05.37 through 9903.06.14, new List additions for critical minerals or semiconductor equipment. Each modeled scenario updates the per-China-origin entry duty stack.

Section 122 sunset and reproclamation. Section 122 authority sunsets 24 July 2026 under the statutory 150-day ceiling. A reproclamation could restart the clock but would require a fresh balance-of-payments emergency finding. The forecast models three states: sunset without reproclamation, sunset with reproclamation at 10 percent, sunset with reproclamation at a different rate.

Section 338 Canada surcharge changes. The August 2026 Section 338 surcharge on Canada. Rate adjustments and country-scope expansions are modeled.

USMCA quota fill and TRQ exhaustion. Canadian aluminum TRQ fill rate, Mexican TRQ surge mechanism triggers, EU 2021 arrangement quota. The forecast tracks quarterly fill and flags entries at risk of falling outside quota.

CBAM phase-in for EU destinations. Q4 2026 reporting mandatory, financial adjustment from 2027. The forecast models the CBAM cost per HS chapter for iron, steel, aluminum, fertilizer, cement, hydrogen, electricity. See CBAM steel quarterly calculator and CBAM default values 2026 steel.

Anti-dumping and countervailing duty administrative review outcomes. Ongoing Commerce administrative reviews for active AD/CVD orders (China steel pipe, Vietnam solar, various others) with expected final results dates. The forecast models expected rate changes.

Base case vs alternative scenarios

Every forecast run starts with a base case: the tariff state as of the forecast date, applied to the portfolio (either historical entry data or projected forward volume). Alternative scenarios are user-configured deviations from the base case.

Typical scenarios a mid-market importer might run:

• Scenario A: Status quo. Current tariff state through the forecast horizon. This is the do-nothing baseline.
• Scenario B: Section 232 raises to 75 percent. Modeled against all 232-exposed entries.
• Scenario C: Section 301 List 4A exclusions expire on schedule. Modeled against all entries currently claiming 4A exclusion codes.
• Scenario D: Section 122 sunsets without reproclamation. All Section 122 charges zero out from the sunset date forward.
• Scenario E: China sourcing shifts 30 percent to Vietnam. Portfolio composition changes, duty stack per-lane changes.
• Scenario F: All of the above. Compound scenario.

Each scenario returns a portfolio-level duty exposure delta vs base case, a per-lane breakdown, and a per-supplier ranking of who bears the burden.

Worked example: aluminum extrusion importer

An aluminum extrusion importer with 12,000,000 USD annual entered value across 200 entries, split 60 percent Mexican-origin USMCA-qualifying and 40 percent Chinese-origin Section 232 covered:

Base case (Q3 2026 tariff state):

• Mexican-origin USMCA: 7,200,000 USD entered value, 0 percent duty = 0 USD.
• Chinese-origin: 4,800,000 USD entered value, 50 percent Section 232 plus 25 percent Section 301 = 3,600,000 USD duty.
• Portfolio duty: 3,600,000 USD.

Scenario B: Section 232 raises to 75 percent on aluminum.

• Chinese-origin duty: 75 percent 232 plus 25 percent 301 = 4,800,000 USD.
• Portfolio duty: 4,800,000 USD. Delta: +1,200,000 USD.

Scenario E: China sourcing shifts 30 percent to Mexico with Canadian-smelt billet (USMCA-qualifying).

• Mexican-origin: 8,640,000 USD, 0 percent = 0 USD.
• Chinese-origin: 3,360,000 USD, 50 percent 232 plus 25 percent 301 = 2,520,000 USD.
• Portfolio duty: 2,520,000 USD. Delta: -1,080,000 USD.

Scenario B + E (compound): Section 232 raises to 75 percent AND 30 percent shift.

• Chinese-origin duty at 75 percent 232 plus 25 percent 301: 3,360,000 USD.
• Portfolio duty: 3,360,000 USD. Delta: -240,000 USD.

Procurement decision: the 30 percent supplier switch offsets the Section 232 raise almost entirely. The switch is worth committing to as a hedge if the probability of the 232 raise is above roughly 20 percent.

Worked example: consumer electronics importer

A consumer electronics importer with 50,000,000 USD annual entered value, split 80 percent Chinese-origin under Section 301 List 3 (25 percent), 15 percent Vietnamese-origin, 5 percent Korean-origin under KORUS:

Base case:

• Chinese-origin: 40,000,000 USD, 25 percent Section 301 plus 10 percent Section 122 = 14,000,000 USD.
• Vietnamese-origin: 7,500,000 USD, 10 percent Section 122 = 750,000 USD.
• Korean-origin under KORUS: 2,500,000 USD, 0 percent = 0 USD.
• Portfolio duty: 14,750,000 USD.

Scenario D: Section 122 sunsets without reproclamation on 24 July 2026.

• Chinese-origin: 40,000,000 USD at 25 percent Section 301 only = 10,000,000 USD.
• Vietnamese-origin: 7,500,000 USD at 0 percent = 0 USD.
• Korean-origin: 0 USD.
• Portfolio duty: 10,000,000 USD. Delta: -4,750,000 USD.

Scenario C: Section 301 List 3 rate raises to 35 percent AND Section 122 sunsets.

• Chinese-origin: 40,000,000 USD at 35 percent = 14,000,000 USD.
• Vietnamese-origin: 0 USD.
• Portfolio duty: 14,000,000 USD. Delta: -750,000 USD (net small decrease).

Procurement decision: Section 122 sunset is the largest positive delta. If the sunset is expected, no procurement action needed; portfolio benefits automatically. If reproclamation is expected, the delta reverses. Hedging via Vietnamese or Korean supplier shift is a smaller lever but positive under both scenarios.

Supplier switching mechanics

Each scenario can carry a supplier-switching assumption. The forecast engine handles:

• Percentage-of-portfolio switches (e.g., 30 percent of China sourcing to Vietnam).
• Per-HS-code switches (e.g., HS 8517.13 shifts entirely to Korea under KORUS).
• Timed switches (e.g., 20 percent shift over 90 days starting from a specified date).

Switching costs are configurable: qualification costs, supplier onboarding, first-article inspection, tooling amortization. The forecast displays gross duty savings vs net-of-switching-cost savings so the comparison is honest.

FTZ and bonded warehouse scenarios

Forecast can model FTZ deferral impact on cash flow. For a Section 232-exposed entry moved into FTZ under 19 CFR 146:

• Duty is deferred until withdrawal for consumption.
• The rate applied on withdrawal is the rate in effect on the withdrawal date, not the admission date.

If a raise is expected within 60 days, FTZ admission before the raise locks in the current rate on withdrawal (subject to FTZ Board approval on the specific commodity). See class III bonded warehouse Section 338 Canada fallback.

Confidence intervals

The forecast engine attaches a confidence interval to each scenario based on the historical volatility of the underlying tariff mechanism:

• Section 232 rate changes: moderate confidence based on Section 232 investigation cycle timing.
• Section 301 List changes: moderate confidence based on Section 301 hearing and Federal Register publication timeline.
• Section 122 sunset/reproclamation: high confidence on sunset date (statutory), moderate on reproclamation.
• USMCA quota exhaustion: high confidence on TRQ fill rate trajectory.

Confidence intervals let procurement weight expected value calculations properly rather than treating every scenario as equally likely.

Push forecast deltas to Slack or Teams

Signed-in enterprise accounts can configure webhook notifications for scenario deltas above a threshold. Common configuration: any scenario with more than 500,000 USD portfolio duty delta pushes to a compliance-and-procurement Slack channel with the scenario summary and top three affected lanes.

Run duty stack forecast on your portfolio

Open landedfees.com/forecast. Upload historical entry data or configure a projected forward portfolio. Add scenarios. The engine returns per-scenario portfolio duty exposure with per-lane breakdowns.

Related guides

• Origin scenario analysis: model landed cost across 20 sourcing lanes
• Section 232 aluminum at 50 percent calculator
• Class III bonded warehouse Section 338 Canada fallback
• CBAM steel quarterly calculator
• Duty leakage: 6 patterns costing importers 3 to 8 percent of imports

Citations

• USITC Harmonized Tariff Schedule: https://hts.usitc.gov
• Section 232 proclamations Federal Register: https://www.federalregister.gov
• USTR Section 301 tariff actions: https://ustr.gov/issue-areas/enforcement/section-301-investigations
• 19 CFR 146 FTZ: https://www.ecfr.gov/current/title-19/chapter-I/part-146
• CBP CSMS notices: https://content.govdelivery.com/accounts/USDHSCBP/subscriber/topics
• CBAM Regulation (EU) 2023/956: https://eur-lex.europa.eu/eli/reg/2023/956/oj