PSC, protest, 1520(d) or drawback: choosing the refund route

Short answer: Overpaid US customs duty can be recovered through one of four routes, and the entry’s liquidation status decides which one is open. Before liquidation you file a post-summary correction (PSC); within 180 days after liquidation you file a protest under 19 USC 1514; for a free trade agreement preference you forgot to claim, a post-importation claim under 19 USC 1520(d) runs for one year from importation; and duty paid on goods you later export or destroy can come back as drawback under 19 USC 1313 for up to five years. IEEPA duties are a special case with their own CBP process, covered separately below.

Refund work starts with a finding: a reclassification memo, an audit spreadsheet, a preference nobody claimed. The finding is the same on every entry it touches; the route is not, because each entry sits at a different point in its life cycle. Below are the routes, the deadlines in one table, and the evidence each route expects. Rates and dates in this article were checked against CBP’s post-summary correction page, CBP CSMS 68340863, 19 USC 1501, 19 USC 1520 and 28 USC 2636 on October 16, 2026.

Start with what you found

The first step is to describe the finding precisely enough that it can be matched to entries. “We overpaid on pumps” is not a finding. “SKU family P-200 was entered under a subheading at 5% when the GRI analysis puts it in a subheading at 1.7%, on 46 entries between March 2025 and September 2026” is a finding, because it names the product, the error, the correct answer and the entries affected.

Three facts about each entry then decide the route: the entry date, the liquidation date, and the kind of error. Liquidation is CBP’s final computation of duty on an entry. An entry not liquidated within one year is deemed liquidated as entered unless CBP extends or suspends liquidation (19 USC 1504), and CBP’s PSC page refers to a 314-day liquidation cycle. The ACE report ES-701, “Courtesy Notice of Liquidation,” lists liquidated entry summaries; pull it before sorting anything.

When does a post-summary correction work?

A post-summary correction works only on an unliquidated entry, and only inside a fixed window. A PSC is an electronic replacement of the entry summary data in ACE (CBP’s Automated Commercial Environment). CBP’s rule is that a PSC can be filed within 300 days from the date of entry and up to 15 days before the scheduled liquidation date, whichever is earlier. ACE rejects a PSC filed outside those limits. There is a narrow exception: if the importer has asked for a liquidation extension, the PSC can go in after day 300, as long as it is still 15 days before the new scheduled liquidation date.

An unliquidated entry is therefore not open “regardless of age.” An entry made 305 days ago is usually past the PSC window even if it has not liquidated, and the route becomes a protest once it does. CBP also lists fields a PSC cannot change, such as port of entry, entry date, importer of record and the 1520(d) trade agreement indicator. Classification, value, origin and special program indicators are the usual PSC corrections, submitted by an authorized ACE entry summary filer, normally the importer’s licensed customs broker.

What does a protest recover after liquidation?

A protest under 19 USC 1514 challenges a CBP decision, including the liquidation itself, and must be filed within 180 days after liquidation or reliquidation. For a classification overpayment, you protest the liquidation at the rate you entered and state the correct classification and why. If CBP allows the protest it refunds with interest; if it denies it, the importer has 180 days from the denial to sue in the Court of International Trade (28 USC 2636(a)). CBP may also reliquidate on its own initiative within 90 days of liquidation (19 USC 1501), but do not plan around that.

Here the point is the clock: day 181 after liquidation closes the protest route on that entry for good.

When does a 1520(d) claim apply?

A 1520(d) claim applies when goods qualified for a free trade agreement preference that nobody claimed at entry. Under 19 USC 1520(d), CBP may reliquidate to refund the excess duties, including merchandise processing fees, without a protest, if the importer files the claim within one year after importation. The statute lists the agreements it covers: USMCA, CAFTA-DR, and the agreements with Chile, Oman, Peru, Korea, Colombia and Panama. The claim must include a written declaration that the good qualified at the time of importation and copies of the certifications of origin, plus anything else CBP requires.

The one-year clock runs from importation, not liquidation, so 1520(d) can be open on an entry whose protest window is already closed, and closed on an entry that has not even liquidated.

When is drawback the right route?

Drawback is the right route when the duty was correctly paid but the goods, or goods made from them, left the country or were destroyed. It is a different kind of refund: nothing about the entry was wrong. Under 19 USC 1313, drawback returns 99% of the eligible duty, and claims must be filed within five years of the date of importation. Substitution claims depend on matching HTS numbers at the 8-digit level, so a wrong code on the import or export side can sink a claim that was otherwise sound.

One sequencing rule: for entries that also carried IEEPA duties, CBP tells filers to request the IEEPA refund before filing drawback on the same entry.

Deadline matrix: which route is open for each entry?

Read the table one entry at a time. Several rows can be open at once.

Route	Legal basis	Window	Clock starts	Typical filer
Post-summary correction	CBP ACE PSC rules	300 days from entry, and at least 15 days before scheduled liquidation, whichever is earlier	Entry date	ACE entry summary filer (usually the broker)
Protest	19 USC 1514	180 days	Liquidation or reliquidation date	Importer or its broker
Post-importation FTA claim	19 USC 1520(d)	1 year	Date of importation	Importer or its broker
Drawback	19 USC 1313	5 years	Date of importation	Claimant, often a drawback specialist broker
IEEPA refund (CAPE)	Court orders and CBP’s CAPE process	Unliquidated, or no more than 80 days after liquidation (Phase 1); finally liquidated entries only for CIT plaintiffs under a court order (Phase 3)	Liquidation date	Importer of record or the filing broker

A worked example across four entries

Take one finding: a reclassification shows a product line should have been entered at 2.5% instead of 6.5% (both rates are example figures). Each entry has an entered value of $80,000, so each one overpaid $80,000 × 4% = $3,200 in duty. Assume today is October 15, 2026.

Entry A was entered 150 days ago and is scheduled to liquidate in about five months. It is inside 300 days and well before the 15-day cutoff, so a PSC recovers the $3,200.
Entry B liquidated 60 days ago. The PSC route is closed. A protest filed in the next 120 days can recover the $3,200 plus interest if CBP agrees with the classification.
Entry C liquidated 210 days ago. The protest window closed 30 days ago, and 1520(d) does not cover classification errors. Unless the goods were later exported or destroyed, which would open drawback, the $3,200 cannot be recovered.
Entry D is a different finding: a Mexican-origin good that qualified for USMCA was entered eleven months ago at the 6.5% general rate with no preference claimed, and it liquidated recently. That is $5,200 of duty plus a $277.12 merchandise processing fee (0.3464% of $80,000). The PSC window has closed, but a 1520(d) claim is open for about one more month, because its clock runs from importation, and a 1520(d) refund covers the merchandise processing fee as well as the duty.

Four entries, four different answers. Across a few hundred entries, that is why the date sort comes before anyone drafts a filing.

How are IEEPA duty refunds different?

IEEPA duty refunds follow a separate process, and the PSC route does not work for them. After the Supreme Court held on February 20, 2026 that the International Emergency Economic Powers Act does not authorize tariffs, CBP stopped collecting those duties on February 24, 2026 and built CAPE (Consolidated Administration and Processing of Entries) in the ACE Portal to refund them. CBP’s CSMS 68340863 says filers may not start an IEEPA refund through a PSC. CAPE Phase 1 accepts unliquidated entries and entries no more than 80 days past liquidation; a protest filed only for an IEEPA refund can be withdrawn so the entry goes into CAPE, if it is still within that 80-day limit.

Entries liquidated more than 80 days ago are where the uncertainty sits as of October 2026: CAPE Phase 3, opened October 6, 2026, takes finally liquidated entries only from importers that are CIT plaintiffs with a court order covering those entries, and the Court of International Trade certified a class of importers on October 8, 2026 without ordering class-wide refunds.

What evidence does each route need?

Every route rests on a written explanation of why the entry was wrong and what the right answer is, backed by documents. What changes is who reads it and how closely.

For a PSC on classification: the corrected HTS number and a classification memo kept on file. ACE accepts the data, but CBP can review the PSC and ask for support through a Form CF-28 (Request for Information).
For a protest: the grounds in writing, with the GRI (General Rules of Interpretation) analysis, the Section and Chapter Notes applied, CBP rulings on similar goods, and product specifications, drawings or photos. A reviewer at CBP will test the argument.
For 1520(d): the written declaration that the good qualified, the certifications of origin, and the rule-of-origin analysis that supports them, which itself depends on the HTS number of the good and its non-originating inputs.
For drawback: import entry data, proof of export or destruction, and, for substitution, records showing the 8-digit HTS match between the imported and substituted goods.

When the finding comes from a spreadsheet comparison, the classification memo is usually the piece nobody has written. TariffWolf stays out of the filing, which remains with your broker or counsel. Its bulk classification service re-classifies the affected SKUs and returns the 6-digit HS code for each with the GRIs applied, the legal notes and the CBP rulings behind it, so the broker or attorney filing the claim picks the 10-digit line from a documented answer.

Mistakes that cost refunds

The first mistake is treating the finding date as the deadline. A team that spends three months perfecting a memo can watch a dozen protest windows close while it writes. File what expires first, with the best evidence available.

The second is assuming the broker tracks liquidation dates for refunds. Unless the service agreement says so, pull ES-701 yourself every month.

The third is ignoring the other direction. A reclassification that lowers one product family’s rate often raises another’s, and known underpayments raise prior disclosure questions under 19 USC 1592. Protesting overpayments while sitting on underpayments creates its own risk. Where penalties, prior disclosure or litigation are in play, bring in a licensed customs broker or trade attorney before you file.

The fourth is filing on a classification that does not hold up. If the new HTS number came from a quick lookup rather than a note-by-note analysis, test it before it goes to CBP.

Frequently asked questions

How far back can I get a customs duty refund?

It depends on the route each entry still qualifies for. A PSC reaches entries up to 300 days old that have not liquidated, a protest reaches 180 days past liquidation, a 1520(d) claim reaches one year from importation, and drawback reaches five years from importation for exported or destroyed goods.

PSC or protest: which one applies to my entry?

A PSC corrects entry summary data before liquidation and must be filed within 300 days of entry and at least 15 days before scheduled liquidation. A protest under 19 USC 1514 challenges the liquidation itself and must be filed within 180 days after it. Once an entry liquidates, the PSC route is closed.

Can I get a refund after liquidation?

Yes, through a protest filed within 180 days of liquidation, through a 1520(d) claim if the issue is an unclaimed FTA preference and one year from importation has not passed, or through drawback if the goods were exported or destroyed. After those windows close, a classification overpayment generally cannot be recovered.

Can I use a PSC to get IEEPA tariffs back?

No. CBP’s CSMS 68340863 says an IEEPA refund cannot be started through a PSC. As of October 2026, IEEPA refunds go through CBP’s CAPE process in the ACE Portal for eligible entries, and older liquidated entries depend on court orders that were still developing.

Sort first, then file. Put every affected entry in the matrix above and file the routes that close soonest. Money on an entry whose window has closed does not come back, however strong the argument.

If the finding behind your refund work is a set of HTS codes nobody has documented, TariffWolf’s bulk classification service re-classifies the SKUs and returns a 6-digit HS code for each with the notes, GRIs and CBP rulings that a PSC, protest or 1520(d) claim needs as support. Your broker completes the HTS line; send a sample file and review the justifications before anything is filed.

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