Unclaimed USMCA preference on past entries: finding the lines and claiming within the year

Why do qualifying goods get entered without the USMCA claim?

A USMCA claim is made at entry, by putting the letters "S" or "S+" in front of the HTS subheading on the entry summary (19 CFR 182.11(b)). The claim rests on a certification of origin that the importer must have in hand when the claim is made (19 CFR 182.12(a)(3)). When the certification is not there on the day the broker files, the broker files at the general rate. Nothing on the entry says "this could have been free"; the line looks like any other dutiable line.

That is why the gap shows up in your own data and nowhere else. The supplier's certification arrives a month later and goes into a folder. A new Mexican supplier is set up in the product master without an origin flag. One broker files with the claim and another does not. None of these is visible on a single 7501, and all of them are visible in an entry export sorted by country of origin.

Since July 24, 2026 the gap costs more. The Section 301 forced-labor action published at 91 FR 47318 added 10 percent on products of Mexico (heading 9903.05.55) and of Canada (heading 9903.05.29), but U.S. note 52(g) and (h) to Chapter 99 exempt products "entered free of duty under the United States-Mexico-Canada Agreement" (headings 9903.05.93 and 9903.05.94). A line that was free under the general rate anyway, and so never carried an indicator, pays 10 percent on entries from July 24, 2026 unless the claim is made. For what else sits on a line, see the post-entry audit pillar.

Which lines in your entry export should you look at?

Work from the broker's entry export or the ACE entry summary line data, not from invoices. The filter is four columns:

1. Country of origin is MX or CA.
2. Special program indicator on the line (column 31 of the 7501, the prefix to the HTS number) is blank. "S" or "S+" means the claim was made; anything else means it was not. The field-by-field guide shows where the indicator sits.
3. The line cost money it need not have. Either the general rate in column 37A is above "Free", or, for entries from July 24, 2026, a Chapter 99 line 9903.05.55 or 9903.05.29 is reported with the line.
4. Date of importation is within the last twelve months. If the export only carries the entry date, pull the arrival date from the carrier's arrival notice or ACE: under 19 CFR 101.1 the date of importation for vessel cargo is the day the vessel arrives within port limits with intent to unlade, and for other modes the day the goods arrive in the customs territory. It is on or before the entry date, never after.

Sort what is left by date of importation, oldest first, and by duty paid. The oldest lines are the ones that expire first; the one-year window in 19 CFR 182.31 runs from importation, not from entry or liquidation.

Then check each product against the rule of origin before anyone files. A Mexican country of origin on the entry means the goods were made or last substantially transformed there for marking purposes; it does not mean they meet the USMCA rule of origin for the tariff line, which may require a tariff shift, a regional value content or both. The supplier's certification is the evidence, and 19 CFR 182.12 says what it must contain. Where the supplier cannot certify, the line stays dutiable.

What does a post-importation claim under 1520(d) need?

19 U.S.C. 1520(d) lets CBP reliquidate an entry to refund excess duties on a good that qualified under USMCA (section 4531 of title 19) when no claim was made at importation, provided the importer files within one year after the date of importation. 19 CFR 182.32(b) lists what the claim must contain:

The claim is filed with CBP at the port of entry or electronically (19 CFR 182.32(a)). CBP's standing guidance on 1520(d) claims (CSMS 18-000612) names the ACE protest module as the electronic platform and accepts paper claims in person or by mail. That message dates from 2018, so its list of agreements for which 1520(d) is the only post-importation route names NAFTA rather than USMCA; for USMCA the current statement is on CBP's post-summary correction page. That page correction page lists the "Trade Agreement (19 U.S.C 1520(d)) indicator for specific special programs, i.e. USMCA" among the data a PSC cannot change. Treat the 1520(d) claim as the route and ask your broker which channel they will use.

The claim can include a classification or valuation change on the same line where that is what makes the line qualify; CBP's 2011 instructions on 1520(d) filings say such changes are handled inside the claim rather than through a separate correction. Keep that narrow: a 1520(d) claim is not the place to fix unrelated errors on the entry.

What comes back, and what does not?

CBP determines whether the entry has liquidated and whether liquidation is final (19 CFR 182.33(a)). On an unliquidated entry the refund is taken into account at liquidation; on a liquidated entry, final or not, CBP reliquidates to make the refund (19 CFR 182.33(c)). Interest on the refund runs from the date of the claim, not from the date of deposit (19 U.S.C. 1505(c)).

Two things do not come back:

• The merchandise processing fee. 19 U.S.C. 1520(d) refunds "excess duties (including any merchandise processing fees)" for the agreements it lists, but the USMCA Implementation Act carved USMCA out of the fee refund. CBP's notice at 85 FR 39576 (July 1, 2020) says section 203 of that Act "eliminates the refund of merchandise processing fees (MPF) for USMCA post-importation claims" and leaves no mechanism to pay it. 19 CFR 182.31 accordingly speaks only of "excess customs duties". A claim made at entry would have taken the fee exemption in 19 CFR 24.23(c)(3); a claim made later does not recover it.
• Anything on a line where the certification fails. CBP may deny a claim after an origin verification finds the good was not originating, or where the claim is late or incomplete (19 CFR 182.33(d)). A denial is protestable under 19 CFR 174.12(e)(2), within 180 days of the written notice of denial.

Whether a post-importation claim also refunds the Section 301 forced-labor duty paid on a Mexican or Canadian line since July 24, 2026 depends on how CBP reads note 52(g) and (h), which exempt goods "entered free of duty under" USMCA. Neither the note nor CBP's implementing guidance (CSMS 69326983, July 23, 2026) addresses post-importation claims, and no CBP guidance answers the question yet. The general duty is the refund you can rely on; ask CBP through your broker whether the claim also refunds the 10 percent before you count on it.

What does a missed claim cost on one line?

The line is molded plastic housings, HTS 3926.90.99, general rate 5.3 percent, "S" in the Special column. No Section 232 list covers the subheading. The entry was filed on August 12, 2026; the vessel arrived in port on August 9, 2026. Entered value $120,000. The supplier's certification of origin, covering the calendar year, arrived in September and was filed away. Illustrative figures.

Had the line been filed as "S 3926.90.99" with the certification in hand: general duty $0, heading 9903.05.94 instead of 9903.05.55 so $0 under Section 301, and no merchandise processing fee under 19 CFR 24.23(c)(3). Total $0.

Filed as a post-importation claim under 19 CFR 182.32 before August 9, 2027:

• The $6,360 of general duty comes back, with interest from the claim date.
• The $415.68 fee does not (85 FR 39576).
• The $12,000 Section 301 layer is the open question above. Even if it is not refundable after the fact, the next entry of the same product, filed with the claim, avoids it.

The same line in your export, with the "S" present, costs nothing; a quick way to price any line both ways on its entry date is the duty calculator.

How do you run this every month instead of once a year?

A claim is cheap to file and expensive to miss. Because the window runs twelve months from each importation, a line found in a review held once a year is often already out of time. The routine that keeps the window open:

1. Each month, filter the previous month's entry lines for MX or CA origin with no indicator and a cost (general rate above Free, or a 9903.05.29 or 9903.05.55 line).
2. Match each product to a certification on file. Blanket certifications under 19 CFR 182.12 can cover up to twelve months; note the period and the certifier.
3. Where there is no certification, ask the supplier now, while the goods and the bill of materials are current. A certification reconstructed a year later is weaker evidence in a verification.
4. Fix the cause. If the broker lacked the certification at entry, give them a standing file; if the product master has no origin flag, add one; if two brokers file differently, align their instructions.
5. Bundle the claims by entry and give the broker the entry numbers, dates and certifications; the claim has the four contents in the table above.
6. Confirm the deadline from the date of importation, not the entry date, and file the oldest first.

Both directions matter. The same export will show lines where "S" was claimed on goods that do not meet the rule of origin; 19 CFR 182.11(c) requires the importer to correct such a claim promptly and pay the duty. See how to recover overpaid import duty for the other correction routes and how long you have to fix a past entry for the clocks that run alongside this one.

TariffSense reads broker entry exports and entry summaries line by line and flags, for each line's entry date, a Mexican or Canadian origin with no special program indicator against a dutiable rate or a Section 301 forced-labor line, with the amount at stake and the importation date the clock runs from. The claim itself stays with your broker. Filing a 1520(d) claim is a customs filing; confirm the route and the evidence with a licensed broker or counsel.