Trade & Sourcing
The Last Quarter Carried One-Third of the Year’s Duties on Less Than One-Quarter of Its Imports
In the fixed 36-family panel, Q4 2025 accounts for 32.99% of full-year calculated duties but 23.52% of customs import value.
Editorial evidence cutoff: September 9, 2026. Published September 29, 2026. Observation periods are stated throughout; older figures are retrospective evidence.
When September 2026 planning relies on a completed annual benchmark, the timing inside that year matters. The 2025 monthly records, already available by September 9, show how the full-year rate can differ from the conditions recorded toward the end of the year. This retrospective tests that averaging problem without treating the final quarter of 2025 as a forecast for the present.
The final quarter of 2025 carried almost one-third of the year’s recorded duties in the long-running manufacturing import panel. It accounted for less than one-quarter of the customs value. That imbalance makes the full-year average an incomplete description of the year’s closing conditions.
Across the fixed 36-family panel, Q4 supplied 32.99% of annual calculated duties and 23.52% of annual customs value. Its observed duty rate was 19.32%, compared with the full-year rate of 13.78%. The quarter’s rate was 40.24% above the annual benchmark.
These are historical observations, not a suggested rate for a current shipment. Their importance is the timing problem they expose: an annual average can be correctly calculated and still answer a different question from the one a budget or purchasing review needs to ask.
THE YEAR DID NOT ARRIVE AT AN EVEN PACE
The first quarter’s observed rate was 4.84%. It rose to 13.66% in Q2, 18.01% in Q3 and 19.32% in Q4. The duty dollars followed that changing relationship to customs value, rather than distributing themselves evenly through the year.
Q1 contained $72.00 billion of customs value and $3.48 billion of calculated duties. Q4 contained $64.93 billion of customs value and $12.54 billion of calculated duties. The later quarter had a smaller import-value base alongside a much larger recorded duty total.
The comparison uses actual monthly USITC DataWeb observations summed into quarters. Each quarter includes the same 36 families. No missing month is replaced with an annual average, and no quarter is estimated from its final month alone.
THE ANNUAL AVERAGE GIVES EARLIER MONTHS THEIR PROPER WEIGHT
The full-year rate is not wrong. It is the ratio of $38.03 billion in calculated duties to $276.02 billion in customs value. It correctly summarizes what was recorded over those twelve months in this panel.
Its difference from Q4 reflects the earlier months that remain inside the denominator and numerator. In a year when the relationship changed substantially, the average necessarily sits below the closing-quarter rate. Calling it the current rate would change the meaning of a valid historical statistic.
The panel definition also matters. These 36 families have a long monthly history, allowing a stable comparison. The broader 57-family annual panel has a different 2025 rate, 12.36%. It would be an error to place that broader rate beside these quarterly figures without stating that the family coverage differs.
THE QUARTER’S SHARE TELLS A SECOND STORY
Q4’s share of annual duties, 32.99%, is considerably larger than its 23.52% share of annual customs value. That pair is useful because it keeps the size of the quarter visible. A high quarterly rate on a very small amount of trade would have a different significance for the annual bill.
Here, the final quarter represents a substantial part of the year’s purchasing base. Its disproportionate duty share cannot be dismissed as the arithmetic of a negligible month. Nor should it be confused with a statement about when companies paid cash; the measure is calculated duty recorded in the trade statistics.
The quarterly shares and rate path reveal separate dimensions of the change. The shares locate the duty dollars within the year; the rates measure duties against each quarter’s own customs value. Q4 stands out on both measures, which makes its larger duty share more than a reflection of import scale alone.
THE PRIOR YEAR PROVIDES A USEFUL CHECK
In 2024, Q4 accounted for 25.36% of annual calculated duties in the same panel. Its observed rate was 3.47%, close to the full-year rate of 3.43%. The later year’s imbalance is therefore not simply a fixed property of how these families’ trade is distributed across the calendar.
That comparison is descriptive rather than a formal counterfactual. Other conditions changed between the years, and a single prior year cannot isolate a policy effect. Its value is that it gives readers a transparent reference instead of implying that every fourth quarter should mechanically carry exactly 25% of duties.
The monthly totals were also reconciled with the separately stored annual records. For both 2024 and 2025, customs values and calculated duties match exactly. The quarterly result is not being produced by incomplete monthly coverage or by comparing incompatible annual and monthly versions of the panel.
AN EXIT RATE IS STILL NOT A FORECAST
Replacing the annual average with Q4 everywhere would introduce a new error. The closing-quarter figure is a historical reading of that quarter’s product, origin and entry mix. It does not establish that the same mix or treatment will persist.
There is a legitimate use for showing both measures. The annual rate describes the completed year. The closing-quarter rate describes how the year ended. A scenario can apply either benchmark to an explicitly hypothetical customs value, but the result remains a scenario until the relevant shipment treatment and purchasing assumptions are verified.
This distinction is especially important when a presentation uses the phrase run rate. Without an identified month or quarter, that phrase can quietly turn an annual statistic into a claim about present conditions. The underlying spreadsheet may be exact while the accompanying language is not.
PUT THE OBSERVATION WINDOW ON THE BUDGET LINE
For a company review, the useful question is which period matches the decision. An explanation of last year’s expense should reconcile to last year’s actual transactions. A sensitivity analysis for a future order should expose its assumptions and verify the item-specific treatment, rather than inherit the annual average by default.
The national panel offers a concrete demonstration of why that distinction is material. The gap between 13.78% and 19.32% is not a rounding detail. It is the difference between averaging an entire changing year and describing its final quarter.
The resulting journalism should resist both overstatements: that the annual average is defective, or that Q4 predicts what every importer will face next. The records support a more useful conclusion. The timing of the burden changed enough that a credible summary needs more than one observation window, with the panel and denominator kept visible beside each.
Source window: all 24 months of 2024 and 2025, 36 matched families and 864 family-month observations. Calculated duties are statistical amounts, with the limitations described in the Census trade definitions.
Sources and evidence
Evidence period: All months of 2024 and 2025; quarters formed from identical 36-family panel. The frozen evidence record lists the source files and verified hashes available September 9, 2026. Source revision: 5e4fb7726c3d40060c0151c086c903baae856cab. Later live-data updates do not alter the historical evidence in this article.
census.gov/foreign-trade/guide/sec2.html
Published 2026-09-29.