September Import Prices Rose 1.1%, Excluding Customs Duties

U.S. import prices rose 1.1% in September, according to the Bureau of Labor Statistics' 16 October 2026 release. An investor researching an importer needs another piece of information before treating that figure as a change in purchasing costs. The prices used in the BLS indexes exclude import duties.

The exclusion limits what the headline measures. It also leaves a practical research question: how did the price before duty and the applicable duty together change the company's bill? A broad import-price index supplies only part of that evidence.

Keep the September observation within its scope

The September monthly rise followed a revised 0.5% increase in August. BLS also reported an 8.1% increase between September 2025 and September 2026. The one-month and 12-month comparisons use different starting dates; neither is an annualised projection of September's pace.

The release's technical note says these indexes are not seasonally adjusted. It describes import prices in U.S. dollars, generally on a free-on-board foreign-port or cost-insurance-and-freight U.S.-port basis, depending on industry practice. Excluding duties therefore does not mean that every other transport or insurance charge is excluded in every industry.

BLS's methodology FAQ states the duty exclusion directly. That definition does not show whether trade policy influenced a negotiated transaction price indirectly. A price series that omits the duty charge cannot, by itself, isolate the causes of changes in the remaining price.

September is the reference month. The figures became public on Friday, 16 October at the publisher-stated 8:30 a.m. Eastern time, or 10:30 p.m. that day in Brisbane, matching the official October calendar. September is first-published data in this edition. BLS permits revisions during the three months after original publication, so retain the release vintage when comparing it with a later download.

A fictional price falls while price plus duty rises

Assume one invented import item, with an unchanged quantity and quality. Its pre-duty unit price is $100 initially and $98 later, a 2% decline. Assume a hypothetical duty equal to 10% of that price initially and 20% later. All amounts are U.S. dollars. There are no other charges, currency changes, exemptions or timing differences in this model.

These are fictional prices and rates. They describe no actual shipment, current tariff schedule, BLS sample item or September price movement.

Initially, the duty is $100 x 0.10 = $10, and price plus duty is $100 + $10 = $110.

Later, the duty is $98 x 0.20 = $19.60, and price plus duty is $98 + $19.60 = $117.60.

The pre-duty price falls 2%, while the model's total rises by $117.60 - $110 = $7.60 per unit. Relative to the earlier total, that is $7.60 / $110 x 100 = 6.91%, rounded.

The duty rate rose by 10 percentage points, from 10% to 20%. Adding those 10 points to the minus 2% price change would give a false 8% total-cost change. The two inputs describe different changes, and the duty amount uses the price in each period as its base.

For this model, write the total as C = P x (1 + t), where P is the pre-duty price and t is the duty rate in decimal form. The total's relative change is therefore P1 x (1 + t1) / [P0 x (1 + t0)] - 1. Multiply by 100 to express it as a percentage.

That formula belongs to the stated assumptions. It is not a reconstruction of the BLS index or a method for assessing an actual customs bill.

Find the offset using the same base

Under those same fictional assumptions, a later 20% duty would leave price plus duty unchanged only if the pre-duty price fell to $110 / 1.20 = $91.6667.... Compared with the original $100, that is an 8.33% decline, rounded.

At $92, the later total would be $92 x 1.20 = $110.40, still above $110. At $91, it would be $91 x 1.20 = $109.20, below $110. Those adjacent cases locate the offset without treating a rounded threshold as an exact invoice price.

If the duty rate stays at 10% in both periods, the original $100-to-$98 price change instead takes the total from $110 to $107.80, also a 2% decline. A fixed proportional charge preserves the percentage change in this stripped-down model. Changing that charge can alter the result.

Actual company research needs the relevant shipment terms and records. Freight already included in a quoted price must not be counted again. The model omits inventory timing, other costs and the company's selling prices; it calculates neither a full landed cost nor a profit margin. No current customs rate or valuation rule is determined here.

Carry the distinction into company and contract research

The September headline cannot supply an importer's product mix, contractual terms, inventory costs or ability to change its selling prices. A company may also purchase goods outside the categories driving the broad index. Establish those exposures from company disclosures before turning a macro observation into a margin assumption.

This differs from the CPI category-overlap problem. There, a subtotal already contains a component. Here, a specified charge is outside the measured price. The research task is to identify the missing cost and its base, without adding an assumed national tariff rate to an aggregate index.

Preparation was at 07:08:52 Australia/Brisbane on Monday, 19 October. Friday, 16 October was the latest completed relevant U.S. regular trading day. The NYSE hours and holiday calendar places its core equity session at 9:30 a.m. to 4 p.m. Eastern, ending at 6 a.m. Saturday in Brisbane. Cboe's dated statistics separately showed Friday's populated 3:15 p.m. Central row. Monday's NYSE core session had not opened. No weekend quote, price reaction or current option valuation is measured here.

An option still requires separate contract evidence. Record its underlying, strike, expiration, multiplier, exercise and settlement terms, quote time, bid, ask and available size. Our options-chain guide explains those fields, and the liquidity guide explains why a displayed midpoint is not a promised fill.

Options Matrix Pro publishes this education and offers commercial options-analysis software. This is general education, not personal financial, legal or tax advice or a recommendation to buy, sell or hold. Buyers can lose the premium; sellers can face larger losses and assignment obligations, including theoretically unlimited loss on an uncovered call. Liquidity, transaction costs, concentration, settlement, funding needs and taxes can change the result. Options are unsuitable when an investor cannot tolerate the relevant loss or fund exercise and assignment. Read FINRA's options guidance and the OCC standardized-options disclosure gateway.

Sources and method

The dated BLS release supplies the September observation. The current summary was checked against that edition. The technical note supplies adjustment, price-basis and revision information; the FAQ supplies the duty exclusion. The official calendar and exchange pages establish the clocks, not a market reaction. Sources were accessed on 19 October 2026 Australia/Brisbane.

All price-plus-duty figures are fictional author arithmetic. No econometric estimate, actual tariff impact, firm-specific margin forecast or option-pricing model is used. Before using an import-price headline in a company worksheet, label its duty treatment and identify which additional company records are needed to estimate the cost being researched.