Everything You Need to Know About Post Summary Corrections
A Post Summary Correction (PSC) is the electronic replacement of an ACE entry summary that an importer or broker files to fix errors before the entry liquidates, and it must be filed within 300 days of the date of entry or 15 days before the scheduled liquidation date, whichever comes first. It is how classification, value, origin, and most other entry summary errors get fixed while an entry is still open. It is also more restricted, more time-sensitive, and more visible to CBP than most importers assume.
A PSC is a correction window, not a general remedy: it is shorter than it looks, it closes for good at liquidation, and every one you file tells CBP something about how well you control your entries.
What a PSC Is, and What It Replaced
A PSC is the only way to electronically correct an ACE entry summary before liquidation. It is transmitted through the Automated Broker Interface, the same channel used for ACE entry summary filing. CBP created it as a test on June 24, 2011 (76 FR 37136), and the same notice ended Post Entry Amendment processing for ACE entry summaries effective September 22, 2011. Fifteen years later it is still formally a test. CBP runs it under 19 CFR 101.9(b), the regulation that lets the Commissioner test planned components of the National Customs Automation Program, and has modified it through a series of Federal Register notices, the most recent published July 6, 2026.
The obligation behind a PSC is not optional. CBP grounds it in 19 U.S.C. 1484 and 1485: an importer who learns that information on an entry was wrong is required to correct it, and the trade, not CBP, is responsible for filing the correction. A PSC is the mechanism for a duty you already have, not a courtesy CBP extends.
A PSC is also not a partial edit. It carries every data element of the original entry summary and replaces it completely, along with any earlier PSC on the same entry. The 2026 notice is precise about what complete replacement does not mean: it does not void the original. Obligations that vested under the original entry stay vested, the date of entry and the date of entry summary filing do not change, and liquidated damages already incurred for a late entry summary are not cancelled by correcting it.
Any authorized ACE entry summary filer can submit a PSC, including one who did not file the original, as long as the same importer of record authorizes it. Importers changing brokers should know the consequence. When a PSC is filed, the original filer is notified and gets full access to the new filing, and every filer on the entry can see its latest version. CBP's notice says plainly that an importer who doesn't want an earlier filer to see a correction's contents should not file it under the test.
The Deadline: 300 Days or 15 Days, Whichever Comes First
The deadline has two parts. A PSC must be transmitted within 300 days of the date of entry, and no later than 15 days before the scheduled liquidation date. Whichever date comes first controls, and ACE automatically rejects a PSC filed after it. There is no late-filing request and no port discretion.
The second limit is the one that catches people. Take an entry dated March 1. Day 300 falls in late December. But CBP's own guidance refers to a 314-day liquidation cycle, and on that cycle the 15-day cutoff falls on day 299, one day before the 300-day limit. On a standard-cycle entry, the 15-day rule is the binding one, and anyone counting to 300 is working from the wrong number. If an entry is scheduled to liquidate sooner, the cutoff moves earlier with it. The practical rule is to calendar the scheduled liquidation date, not the date of entry.
The window has changed before. Until November 1, 2017, a PSC had to be filed within 270 days of entry and could not be filed within 20 days of scheduled liquidation. CBP moved to the current 300 days and 15 days in 82 FR 50656 to give filers more time. Anything that still says 270 days is out of date.
There are two exceptions, and both are narrow. If the importer requested and CBP granted an extension of liquidation under 19 CFR 159.12, the 300-day limit falls away, but the PSC must still be filed at least 15 days before the new scheduled liquidation date. And for entries whose liquidation is suspended beyond 300 days after entry, a PSC can be filed after day 300 if the entry carries a qualifying suspension basis at the time of filing: CVD Suspend, ADD Suspend, AD/CVD Suspend, Subject to EAPA, or Subject to Court Injunction. That reaches Type 03 AD/CVD entries under suspension and entries held in an EAPA investigation. CBP allowed this in practice from 2022, and the 2026 notice formalized it.
None of this extends the life of the entry itself. An unextended, unsuspended consumption entry still liquidates within a year of entry, and if CBP doesn't act in time it is deemed liquidated by operation of law. The PSC test adds one clarification: when a PSC has been properly filed, deemed liquidation happens at the rate, value, quantity, and duties asserted in the most recently accepted PSC, not the original summary.
Can You File? The Eligibility Checklist
Being inside the window is necessary but not sufficient. The entry summary, or the last PSC filed on it, has to meet every condition CBP sets. It must be in accepted status, meaning it has passed all technical edits and validations. It must be in CBP control, which in CBP's terms means it has been placed on a statement, rather than in trade control. It must be fully paid, which ties PSC eligibility to duty-paid status: CBP will not process a PSC until the summary it replaces is paid. And it must be unliquidated.
For an entry on a Periodic Monthly Statement, paid means the statement payment has actually been received, which CBP says can take up to 45 days after the entry date.
Three more conditions block a PSC regardless of timing. The entry cannot be under CBP review; if it is, ACE returns the message that a PSC is not allowed under CBP review. The entry cannot be associated with a protest. And if the entry was flagged for reconciliation, a PSC can correct it only on issues other than the flagged one.
There is no cap on the number of PSCs for a single entry, except that PSCs that have been team reviewed are not eligible for further PSC submissions. Since August 5, 2026, an unpaid increase from one PSC also blocks the next, as covered below.
What a PSC Can Fix, and What It Can't
A PSC can carry revenue changes, meaning anything that changes duties, taxes, or fees regardless of amount, and non-revenue changes to any data the entry summary requires. That covers the corrections that matter most: HTS classification and the Chapter 99 numbers reported with it, entered value, country of origin, and quantities.
Entry type is the tightest constraint. The only entry type changes permitted are 01 to 03 and 03 to 01, consumption to AD/CVD and back. A PSC also cannot change data that would turn a Type 23 temporary importation under bond into another entry type, or the reverse, so a classification change that would take merchandise out of TIB eligibility can't be made by PSC.
A longer list of fields can't be changed at all, and CBP rejects any PSC that tries: the importer of record, the date of entry, the date of entry summary, the bond and surety code, the port of entry, the consolidated summary indicator, the live entry indicator, the cargo release certification request indicator (including DOT, FDA, and PGA grouping), the location of goods code, the reconciliation issue code, Periodic Monthly Statement data including the preliminary statement print date and statement client branch identifier, any release detail, and the trade agreement indicator for programs claimed under 19 U.S.C. 1520(d), such as USMCA. A wrong importer of record has its own fix. The importer or broker files CBP Form 3347, CBP updates ACE, and only then can a PSC correct anything else.
Every PSC needs at least one reason code, at the header or line level, up to five, plus a text description of the change. A reason code that says classification changed, paired with a description that says only that the item was reclassified, tells CBP what happened without telling it why the new code is right.
Paying for a PSC: The 2026 Rules
On July 6, 2026, CBP published 91 FR 41053, and on August 3 it announced the changes in CSMS # 69428352. The Federal Register notice republishes the entire PSC test with the changes in place, and the CSMS message explains the ACE mechanics. The new rules took effect August 5, 2026.
The headline change is that an increase in duties, taxes, or fees resulting from a PSC must be paid electronically through ACH, by ACH debit or ACH credit. Checks and cash are no longer accepted, and the importer has to be enrolled in one of the ACH processes before it can pay. Increases in AD/CVD have their own, faster rule: they must be paid by ACH within three business days of submitting the PSC.
The increase must be paid in full. A filer can pay it when the PSC is submitted, or wait to be billed for the full amount at liquidation, but partial payment is not accepted. The two choices are not equal. ACE will not accept a subsequent PSC on the entry until the increase from the previous one is paid in full and processed by CBP. A filer who chooses to wait for the bill has, in effect, filed its last PSC on that entry.
Interest works differently. CBP will not accept an interest payment on a PSC before liquidation. Interest on the underpayment is assessed at liquidation under 19 U.S.C. 1505, running from the date the estimated duty was due until full payment is made, and the importer pays it when CBP bills it. CBP says the clarification is meant to ensure payments apply properly to open bills and to improve its enforcement of PSCs. That last phrase comes back below.
Getting Money Back
A PSC that lowers duty does not produce an immediate refund. Because a PSC is treated as a new entry summary, it liquidates like one, and the overpayment is refunded at liquidation, which on a standard cycle can be most of a year after entry. A filer can request accelerated liquidation on the PSC. When it does, the PSC liquidates on the weekly cycle, and CBP says it aims to process the request within 60 calendar days of receipt.
Section 301 exclusions are a familiar driver of refund PSCs. When USTR grants or extends an exclusion that reaches back to entries already filed, the open entries can be corrected by PSC to report the exclusion's Chapter 99 subheading, with the refund following at liquidation, while liquidated entries need a protest instead. The mechanics are covered in Section 301 duty refunds and liquidation adjustment, and the monitoring problem behind them in Section 301 Exclusions: Retroactivity, Expiration, and the Federal Register Trap. Every week an applicable exclusion goes unnoticed, more entries pass the 15-day cutoff and move to the protest route.
The largest refund event in years runs outside the PSC entirely. After the Supreme Court held on February 20, 2026, in Learning Resources, Inc. v. Trump, that IEEPA does not authorize tariffs, CBP built a separate refund process, CAPE, for IEEPA duties. CSMS # 68340863 states that filers are prohibited from initiating an IEEPA duty refund request by filing a PSC. The PSC remains the tool for other corrections on those entries; CBP directed, for example, that PSCs claiming duty-free treatment for the October 2025 to February 2026 lapse of the AGOA and Haiti HOPE/HELP programs be filed before the CAPE declaration. Removing IEEPA duty is not one of the things a PSC is for.
PSC vs. Reconciliation vs. Prior Disclosure vs. Protest
Post-entry corrections are easiest to sort by when they are available. There are four, and liquidation is the dividing line.
Before liquidation, there are two. The PSC is the default for any entry inside its window. Reconciliation is the alternative for entries flagged when the entry summary was filed, usually because value, classification, or another element genuinely couldn't be known yet, and it is a separate filing on its own timeline. The two interact: on a flagged entry, a PSC can fix anything except the flagged issue. Because reconciliation generally has to be flagged at filing, for most routine errors discovered later the PSC is the only pre-liquidation option.
After liquidation, the PSC is gone. CBP's guidance names the remaining options as a prior disclosure or a protest. A protest challenges the liquidated result and is generally due within 180 days of liquidation. A prior disclosure is a voluntary report of a violation, made before CBP begins a formal investigation, that limits penalty exposure under 19 U.S.C. 1592. How those two differ, and why a CF-29 changes which one is available, is the subject of this guide's companion piece, Prior Disclosure vs. a CBP Protest.
Put as a sequence: an open, unflagged entry inside the window gets a PSC; the flagged issue on a reconciliation entry goes to reconciliation; an error found after liquidation calls for a choice between protest and prior disclosure. An error found just before the 15-day cutoff forces a choice between a rushed PSC and a post-liquidation remedy, which is the best argument for finding errors sooner.
Correcting an HTS Misclassification by PSC
Classification errors rarely affect a single entry. If a product was entered under the wrong subheading, it was usually entered that way every time it shipped, and those entries sit at different stages. The open ones inside the window get PSCs. The ones past the cutoff or already liquidated need a different route.
That split matters because a PSC is not a prior disclosure. It corrects the entries it reaches and nothing else. It gives no penalty protection for liquidated entries carrying the same error, and filing PSCs on recent entries while saying nothing about older ones does not cure the older ones. Where the error underpaid duty, the question of whether those older entries reflect a violation under 19 U.S.C. 1592, and whether the importer exercised reasonable care, does not go away because the newer entries were fixed. That is a question for counsel, but it has to be asked.
A duty-lowering reclassification deserves extra care. In practitioners' experience it is the kind of PSC most likely to draw a question, and its reason code and description are in ACE for CBP to read. Before filing one, assemble the documentation that would answer a CF-28 about it: the product facts, the headings considered, the notes that decided it, and any rulings relied on. If CBP disagrees, the next document is a CF-29, and the strength of the response depends on how well the new classification was documented when it was made.
This is the same gap described in Why the Same Product Gets Two Different HTS Codes from Two Different Brokers: a classification without a recorded rationale can't be defended on the merits. What a Focused Assessment Actually Audits makes the related point that CBP measures reasonable care separately from accuracy, and a well-documented correction is evidence of the first even when it concedes a lapse in the second.
Why PSCs Are a Problem in the New Trade Environment
Everything above treats the PSC as a tool. It is also a record, and that is where it gets uncomfortable. A PSC is evidence that an error wasn't caught when the entry summary was filed. The importer found out weeks or months later. One PSC is housekeeping. A steady stream of them reads as a sign that the importer's entries are not under control at the point they are filed.
Nothing about a PSC is private. Each one, with its reason codes and description, sits in ACE alongside the original summary. CBP selects entries and importers for review on the basis of risk, using its data, and the PSC history is part of that data. CBP has not published a rule that a given number of PSCs triggers review, and this guide does not claim one exists. But it is a common view among practitioners that a pattern of PSCs, especially classification and value corrections and especially corrections that lower duty, is the kind of signal that leads to CF-28s and can contribute to selection for a Focused Assessment or a narrower Quick Response Audit. Put bluntly, in that view: the more you file, the more you look like a target.
CBP's own language points the same way, even if it stops short of saying so. The 2026 notice describes its interest clarification as intended to improve CBP's enforcement of PSCs, and the test's misconduct provisions list failure to exercise reasonable care as a ground for penalties, liquidated damages, or suspension from the test. CBP treats PSC filing as something it enforces, not only something it processes.
The trade environment is making errors easier to make. The overlay layer of the tariff has rarely moved faster. Chapter 99 provisions change through proclamations, Federal Register notices, and CSMS guidance, sometimes week to week, and each change is a chance to file an entry against yesterday's rules. Section 232 coverage has grown through derivative product expansions that pull downstream goods into steel and aluminum duties. Section 301 exclusions are granted, extended, and allowed to lapse on their own schedule, and an exclusion code claimed after it expired is an underpayment. The IEEPA tariffs added country-specific rates that changed repeatedly before the Supreme Court struck them down, and their unwinding through CAPE put a vast number of entries back in motion, with CBP directing certain corrections on them to be made by PSC first. Refund-driven PSCs for exclusions and program lapses add volume of their own. And since August 2026, the payment rules mean an unpaid increase on one PSC blocks the next.
None of this is an argument for filing fewer PSCs that are required. The duty to correct comes from statute, and an importer who knows an entry is wrong and leaves it uncorrected is in a far worse position than one who corrects it, however many corrections that takes. The goal is not to file fewer PSCs. It is to need fewer of them, by moving error detection from after filing, where it produces a correction record, to before filing, where it produces a correct entry.
Catching Errors Before CBP Does: Technology Options
Most importers learn about entry errors after the fact, from a sample, a broker's note, or an audit. Moving that check earlier is a technology problem, and there are two broad ways to approach it.
The first is to build it. A real-time entry audit tool pulls entry data from ACE or the broker's ABI feed and checks each line against current rules: classification against the product, Chapter 99 stacking against origin and date, AD/CVD scope, value, and origin. It can be built, and building gives full control. It is also expensive, slow to stand up, and hardest of all to maintain, because the rules it checks against don't hold still. Weekly CSMS messages, new proclamations, and HTSUS revisions all have to reach the checks before the entries they affect are filed, or the tool quietly validates against last month's law.
The second is to buy an automated entry audit service. Two examples are VAO and 3rdwave, both of which provide automated audit of customs entries.
Whichever route, four questions separate a useful tool from a reporting layer. First, does it review entries before they are filed, after, or both? Pre-filing review prevents the PSC; post-filing review finds the PSC you need while the window is still open. Both have value, but they are not the same thing. Second, what does it cover? A tool that checks classification but not Chapter 99 stacking, or value but not origin, leaves the most volatile layer unchecked. Third, how fast do rule changes reach the checks? Ask for the lag between a CSMS message or proclamation and the updated check, because that lag is the window in which the tool approves wrong entries. Fourth, does it leave an audit trail you can show CBP, recording what was checked, against which version of the rules, and what was flagged? A check that can't be evidenced does little for you in a review.
Why This Is a Classification Problem First
The cheapest PSC is the one you never file. Many of the errors PSCs exist to fix start as classification decisions: the wrong heading, a missed note, a Chapter 99 provision applied to the wrong base code. Those errors are made upstream of the entry summary, before any broker transmits anything, and they repeat on every entry that uses the code.
Kanon works at that point. Its deterministic GRI traversal returns the same HTS code for the same product facts against the same tariff version, and its Classification Support Package records the facts, the provisions and notes evaluated, the rule that resolved the classification, and the tariff version it was resolved under. That record is what keeps a correct classification from turning into a PSC. And when a classification does need to change, because the facts were wrong or the law moved, the CSP is the documented rationale behind the PSC's reason code: the answer to the CF-28 before it is asked.
Frequently Asked Questions
What is the deadline for filing a Post Summary Correction?
A PSC must be filed within 300 days of the date of entry and no later than 15 days before the scheduled liquidation date, whichever comes first. ACE automatically rejects late PSCs. On the standard 314-day liquidation cycle, the 15-day cutoff falls on day 299, so it is usually the binding limit. Exceptions apply when CBP has granted a liquidation extension (the 15-day limit still applies) and for entries whose liquidation is suspended beyond 300 days on a CVD, ADD, AD/CVD, EAPA, or court-injunction basis.
Can I file a PSC after the entry liquidates?
No. A PSC can only be filed on an unliquidated entry. After liquidation, CBP's guidance is that the remaining options are a prior disclosure or a protest, and a protest is generally due within 180 days of liquidation.
What is the difference between a PSC and a Post Entry Amendment?
A Post Entry Amendment was the earlier way to correct an entry before liquidation. CBP stopped accepting Post Entry Amendments for ACE entry summaries effective September 22, 2011, when the PSC test took over (76 FR 37136). A PSC is filed electronically through ABI and completely replaces the entry summary rather than amending individual fields.
Does filing PSCs increase CBP scrutiny?
CBP has not published a threshold at which PSCs trigger review. But every PSC and its reason codes are visible in ACE, and practitioners commonly treat a pattern of PSCs, especially duty-lowering classification or value corrections, as a risk signal for CF-28s and audit selection. That is not a reason to skip a required correction. It is a reason to catch errors before filing so fewer corrections are needed.
How long does a PSC refund take?
A refund from a duty-lowering PSC is issued when the entry liquidates, because the PSC liquidates like any other entry summary. A filer can request accelerated liquidation on the PSC; the PSC then liquidates on the weekly cycle, and CBP aims to process the request within 60 calendar days of receipt.
Can a new broker file a PSC on an entry another broker filed?
Yes. Any authorized ACE entry summary filer can file a PSC on an entry summary filed by someone else, as long as the same importer of record authorizes it. The original filer is notified and gets full access to the new filing, so the importer should be comfortable with every filer on the entry seeing the correction.