Post Summary Correction (PSC): Deadlines, ACE Filing, and Reason Codes

A post summary correction is the electronic filing that lets an importer fix an entry summary U.S. Customs and Border Protection has already accepted, before that entry liquidates. It runs through the Automated Commercial Environment and has to reach CBP within 300 days of the date of entry and no later than 15 days before the scheduled liquidation date, whichever comes first.¹ Miss that window and your only remaining tool is a formal protest after liquidation, which is slower, more restrictive, and available only within 180 days of the liquidation date.²

The Two Deadlines That Control Your Filing

Two clocks run at the same time. The PSC has to be submitted within 300 days from the date of entry, and it has to arrive at least 15 days before the scheduled liquidation date.¹ The default liquidation window is one year from the date of entry, though CBP can extend it up to a total of four years.³ If an entry has been open for 285 days with no extension, the 15-day pre-liquidation cutoff can arrive before the 300-day mark, so the math tightens fast late in the cycle.

ACE automatically rejects any PSC filed outside these windows. There is no grace period and no discretion involved.¹

AD/CVD and Suspended Entries

Entries subject to antidumping or countervailing duty orders often sit in suspended status for years while the Department of Commerce completes reviews. A filer may submit a PSC outside the standard 300-day window when the entries are Type 03, Type 07, or Type 06 with a case number, are in suspended status, and carry a suspension basis such as ADD Suspend, CVD Suspend, or Subject to Court Injunction.¹

Asking CBP to Extend Liquidation

If you find an error after the 300-day mark but before liquidation, one option is to request a liquidation extension in writing before the current liquidation period expires. You have to show “good cause,” which generally means demonstrating that more time is needed to present information affecting the pending action.⁴ Each extension adds up to a year, capped at three years beyond the original one-year period.³ An approved extension reopens the PSC window because the 15-day pre-liquidation cutoff now falls later.

What a PSC Can and Cannot Change

Both revenue and non-revenue changes are allowed. Revenue changes affect the duties, taxes, or fees owed: a reclassification that shifts the duty rate, a corrected declared value, or an updated country of origin that triggers a different tariff. Non-revenue changes update required entry summary information without changing what you owe, such as the mode of transportation or the consignee number.¹

The PSC covers consumption entries, warehouse entries, temporary importation bonds, foreign trade zone consumption, AD/CVD entries, and several other types, including 01, 02, 03, 06, 07, 21, 22, 23, 31, 32, 34, 38, 51, and 52. One boundary matters: the only entry-type conversion a PSC allows is between Type 01 (consumption) and Type 03 (AD/CVD). No other entry-type swaps are permitted through this process.¹

Something else trips up first-time filers. A PSC is not a surgical edit. It replaces the entire entry summary. The system treats each PSC as a new filing that overwrites the original and any previously filed PSCs for that entry.⁵ Every data element from the original filing has to be included in the PSC submission, not just the fields you want to change. Accidentally omit a correct line item and the replacement will not contain it.

Filing Through ACE

Customs brokers and self-filing importers transmit the PSC through the Automated Broker Interface in ACE. Because the PSC replaces the full entry summary, the transmission includes every data element.⁵ An authorized filer can submit a PSC against another filer’s original entry summary, as long as the same importer of record has authorized both.¹

ACE runs the submission through its existing validations, including Census warnings, and returns an acceptance or rejection message in real time.⁵ There is no cap on how many PSCs you can file against the same entry summary, provided each one lands inside the allowable timeframe.¹

What ACE Requires Before Accepting

For ACE to accept a PSC, the original entry summary has to meet all of the following:¹

Accepted status, meaning it passed all technical edits and validations.
Not under CBP review. If personnel have flagged the entry for examination, the system blocks PSC submissions until the review concludes.
In CBP control, meaning the entry has not been transferred out of CBP’s jurisdiction.
Fully paid. Any duties, taxes, and fees on the original entry have to be paid. On a Periodic Monthly Statement, the entry must be “truly” paid, meaning the PMS cycle has closed and payment has cleared.
Not yet liquidated. Once liquidation happens, the PSC path is closed.

Rejections

ACE rejection messages identify the specific problem, whether a timing violation, a formatting error, or an entry under review. A formatting rejection is easy: correct and resubmit within the filing window. A rejection because the entry is under CBP review means waiting until the review concludes. A rejection based on timing means the window has closed, and a formal protest after liquidation is likely the only remaining path.

Reason Codes and Supporting Documentation

Each PSC has to include the original entry summary number, the complete set of data elements from the original filing with corrections applied, and one or more reason codes explaining what changed. CBP allows up to five reason codes per PSC at the header level, the line level, or both.¹ A description field accompanies the codes for additional context.

Header codes cover entry-wide changes: entry type conversions between AD/CVD and non-AD/CVD, mode of transportation, bond surety, consignee, date of importation, state of destination, header-level fees, and a catch-all “other” code. Line codes pinpoint changes to a specific product line: invoice changes or missed lines, trade agreement or special program claims, HTS classification, value, non-dutiable charges, duty amount, country of origin, country of export, AD/CVD case attributes, ruling number, MPF and other fees, manufacturer or supplier, and foreign exporter.⁶ Your broker or ACE interface presents the full list at filing time.

Beyond the reason codes, prepare a written statement of facts explaining the nature of the error and the evidence behind the corrected data. Compare the commercial invoice and packing list against the original CBP Form 7501 to identify every field needing adjustment. If the correction involves claiming preferential tariff treatment, have the certificate of origin ready. For valuation changes, updated worksheets or manufacturer affidavits showing the correct price strengthen the filing.

Paying Additional Duties and Interest

A PSC is treated as a new entry summary for payment purposes, and CBP will not process it until all duties, taxes, and fees on the corrected filing are fully paid.¹ If the correction increases duty owed, you tender the additional amount at filing. If it decreases the amount owed, the overpayment is resolved at liquidation.

Interest accrues on underpayments from the date the estimated duties were originally due through the date of liquidation.⁷ For the first quarter of 2026, CBP applies a 7% annual rate on underpayments. Overpayment refunds earn the same 7% for non-corporate importers, and 6% for corporations.⁸ These rates adjust quarterly with the federal short-term rate, so check the current Federal Register notice before calculating. Balances still unpaid more than 30 days after liquidation pick up additional delinquency interest.

After ACE Accepts the PSC

Import specialists review the updated data and any supporting documentation. They can accept the corrected figures, or they can ask for more information. That request typically arrives as a CBP Form 28, which gives you 30 days to respond.⁹ Do not ignore a Form 28. CBP is authorized to issue penalties for willful failure to provide requested records of up to $100,000 or 75% of the appraised value per release, whichever is less. Negligent failure can still draw penalties of up to $10,000 or 40% of appraised value per release.¹⁰

Once review is complete, the corrected entry moves into liquidation, the official closing of the entry record that settles final duties, taxes, and fees owed. The PSC liquidates the same way any other entry summary would.¹ You can watch the status in ACE. If an entry is not liquidated within one year of the date of entry, and no extension or suspension applies, it is deemed liquidated at the rate, value, and duty amount the importer originally asserted.³

When a PSC Alone Is Not Enough

A PSC fixes the data on your entry summary. It does not automatically shield you from penalties if the original error violated customs law. Under 19 U.S.C. § 1592, entering goods with materially false or misleading information, even through negligence, exposes an importer to civil penalties reaching the full domestic value of the merchandise for fraud, four times the lost duties for gross negligence, or two times the lost duties for ordinary negligence.¹¹

The tool that reduces that exposure is a prior disclosure. Report the violation to CBP before the agency begins a formal investigation, and the penalty for negligence and gross negligence drops to just the interest on unpaid duties, provided you also tender the unpaid duties within 30 days of CBP’s calculation.¹¹ Even for fraud, a prior disclosure caps the penalty at 100% of lost duties rather than the full domestic value of the goods. The catch: you carry the burden of proving you had no knowledge that an investigation had already started.

The practical point is that when the error is significant, especially misclassification, undervaluation, or incorrect origin reporting that produced lower duties, filing a PSC to fix the data and making a prior disclosure to address the legal violation at the same time gives you the strongest position. A PSC without a prior disclosure corrects the record but leaves the penalty question open.

On a $500,000 shipment where you underpaid $20,000 in duties through negligence, the maximum penalty without a prior disclosure is $40,000. With a timely prior disclosure and tender of the unpaid duties, the penalty drops to just the interest accrued on that $20,000.

If the Window Has Already Closed

Once an entry has liquidated, the PSC path is permanently closed. The remaining option is a formal protest under 19 U.S.C. § 1514, which has to be filed within 180 days after the date of liquidation. Protests can challenge the appraised value, the classification and duty rate, the liquidation itself, and other CBP decisions adverse to the importer.²

A protest is filed on CBP Form 19 or electronically through ACE, and it has to specifically identify each contested decision, the affected merchandise, and the reasons for the objection. Only certain parties can file, primarily the importer of record, the consignee, their sureties, or an authorized agent.¹² Unlike a PSC, a protest doesn’t replace the data. CBP reviews the protest and issues a decision, which the importer can appeal to the U.S. Court of International Trade if the outcome is unfavorable. That process is far more formal and adversarial than a PSC, which is why catching errors before liquidation saves time, money, and legal risk.

Keeping the Records That Support Your Filing

Every record supporting an entry, including invoices, packing lists, valuation worksheets, certificates of origin, and any documentation backing a PSC, has to be retained for five years from the date of entry.¹³ The five-year clock applies to importers, entry filers, consignees, and anyone who knowingly caused the importation.¹⁴ Willful failure to produce records when CBP demands them carries penalties of up to $100,000 per release.¹⁰

1
U.S. Customs and Border Protection. Post Summary Correction
2
Office of the Law Revision Counsel. 19 USC 1514 – Protest Against Decisions of Customs Service
3
Office of the Law Revision Counsel. 19 USC 1504 – Liquidation or Reliquidation of Entries
4
eCFR. Extension of Time for Liquidation
5
Federal Register. Post-Summary Corrections to Entry Summaries Filed in ACE Pursuant to the ESAR IV Test
6
U.S. Customs and Border Protection. ACE CATAIR Entry Summary Create/Update
7
Office of the Law Revision Counsel. 19 USC 1505 – Payment of Duties and Fees
8
Federal Register. Quarterly IRS Interest Rates Used in Calculating Interest on Overdue Accounts and Refunds of Customs Duties
9
U.S. Customs and Border Protection. CBP Form 28 – Request for Information
10
Office of the Law Revision Counsel. 19 USC 1509 – Examination of Books and Witnesses
11
Office of the Law Revision Counsel. 19 USC 1592 – Penalties for Fraud, Gross Negligence, and Negligence
12
eCFR. 19 CFR 174.12 – Filing of Protests
13
eCFR. 19 CFR 163.4 – Record Retention Period
14
eCFR. 19 CFR 163.2 – General Recordkeeping Requirements