PSC, protest or prior disclosure: which fix for which customs error

The entry was accepted weeks ago. The goods are long gone from the terminal. Then someone on the desk notices that the declared value doesn't match the invoice, or the country of origin was keyed from the wrong line, or the HTS number was taken from last season's shipment.

Once an entry summary has been accepted, the error can no longer be fixed as a reject can (that is a different problem with its own clock). There are three ways to correct it: a post summary correction, a protest, or a prior disclosure. They are not interchangeable. Which one you can use depends mostly on two dates and one question, and picking the wrong one can mean missing a deadline you didn't know was running.

This post is a decision guide for the person doing the filing. It is not legal advice. Where money or penalty exposure is significant, the importer of record should be talking to a customs attorney, and the last section says when.

The decision table

Ask these three questions in order:

1. Has the entry liquidated?
2. Is CBP already reviewing it, or investigating?
3. Is this a one-off mistake, or has the same error been made on other entries?

Situation	Usual tool	Deadline
Not liquidated, not under CBP review, one-off error	Post summary correction (PSC)	300 days from entry, or 15 days before scheduled liquidation, whichever is earlier
Not liquidated, but the entry is under CBP review	No PSC. Work through the review itself	Whatever the request from CBP sets
Liquidated, and the error is in the entry or the liquidation	Protest	180 days from the date of liquidation
The error may be a violation of 19 USC 1592 (a material false statement or omission) and it repeats across entries, liquidated or not	Prior disclosure, usually with counsel	Before a formal investigation of that violation begins

The rest of this post explains each row.

Post summary correction: the default before liquidation

A PSC replaces the data on an accepted entry summary in ACE. It can correct value, quantity, classification, origin and most other entry summary data, and it works in both directions: a PSC that lowers the duty owed leads to a refund.

The window is narrow. According to CBP's PSC page, a PSC can be filed within 300 days of the date of entry and at least 15 days before the scheduled liquidation date, whichever is earlier. ACE automatically rejects a PSC filed outside that window. There are narrow exceptions, such as entries with an extended liquidation date and certain AD/CVD-suspended entries.

The same CBP page sets the conditions. The entry summary must be:

• accepted (a rejected summary is corrected and resubmitted, not PSC'd);
• paid (for entries on a periodic monthly statement, the statement must actually have been paid);
• unliquidated; and
• not under CBP review. ACE answers a PSC on an entry in review with a "PSC not allowed under CBP Review" message.

There is no limit on the number of PSCs for one entry summary while the window is open. The exception is an entry that has been through a team review.

One more point that catches people out: a PSC is not a prior disclosure. CBP asked filers not to use PSCs as a way to make a prior disclosure when it set up the process (76 FR 37136, 24 June 2011). If the error could be a 1592 violation, correcting the data does not by itself protect the importer.

If CBP is already reviewing the entry, for example after a CBP Form 28, the fix goes through that review instead. What goes in the file you send back is covered separately.

Liquidation: the line that changes everything

Liquidation is CBP's final computation of the duties on an entry. By law an entry not liquidated within one year of the date of entry is deemed liquidated at the value, rate and amount the importer declared, unless liquidation is extended or suspended (19 USC 1504; 19 CFR 159.11).

In practice most entries liquidate well before the year is up. ACE places entries in an automated liquidation cycle 314 days after entry (CBP CSMS #48407264), so for most entries the "15 days before liquidation" limit and the 300-day limit fall close together. Don't work it out by hand: check the scheduled liquidation date in ACE for the specific entry, because extensions and suspensions move it.

Protest: after liquidation, 180 days

Once an entry has liquidated, a PSC is no longer available. CBP's PSC page names the two remaining routes: a protest or a prior disclosure.

A protest challenges a CBP decision, and liquidation is one. Under 19 USC 1514, decisions that can be protested include the liquidation of an entry and any clerical error, mistake of fact or other inadvertence in an entry, liquidation or reliquidation. So an error the filer made can be corrected by protesting the liquidation that adopted it.

The deadline is 180 days after the date of liquidation (19 USC 1514(c)(3)). Count from the date posted in ACE, not from when anyone noticed. According to CBP's protests page, protests are filed on CBP Form 19 or electronically in the ACE Protest module, and the importer, its broker or its attorney can file them. The procedures are in 19 CFR Part 174.

If a protest is denied, the next step is the Court of International Trade. At that point the importer needs counsel, not a better-worded Form 19.

Prior disclosure: when the problem is bigger than one entry

PSCs and protests fix entries. A prior disclosure deals with penalty exposure. It is the importer telling CBP about a possible violation of 19 USC 1592 (entering goods by means of a material false statement or omission, whether through negligence, gross negligence or fraud) before CBP finds it.

The typical trigger is a pattern rather than a single slip: the same wrong value basis, origin or classification repeated across many entries, some of them already liquidated.

Under 19 CFR 162.74, a valid prior disclosure:

• discloses the circumstances of the violation to CBP before, or without knowledge of, the commencement of a formal investigation of that violation; and
• tenders the actual loss of duties, taxes and fees, either at the time of disclosure or within 30 days of CBP's written notice of its calculation. Failing to pay the amount CBP finally calculates means the disclosure is denied.

There is no fixed filing window like the PSC's 300 days. The practical deadline is the start of a formal investigation of that violation, and the importer will not always know when that has happened. Waiting has a cost.

The reason to do it is the penalty cap. Without a prior disclosure, 1592 penalties can reach the domestic value of the merchandise for fraud, the lesser of domestic value or four times the lost duties for gross negligence, and the lesser of domestic value or twice the lost duties for negligence. With a valid prior disclosure, 19 USC 1592(c)(4) reduces the cap to 100 percent of the lost duties for fraud, and to interest on the lost duties for negligence or gross negligence. CBP's Prior Disclosure informed compliance publication explains the process in plain terms.

Whether a set of errors amounts to a 1592 violation, how far back to look, and how to word the disclosure are legal questions. The broker's job is usually to spot the pattern and assemble the entry data. The importer and its counsel decide what to disclose.

A worked example: one error, three outcomes

This is an invented example to show how the dates interact. The numbers are illustrative, not taken from a real entry.

An entry is filed with an entry date of 12 January 2026. The commercial invoice says USD 38,450. The entry summary was transmitted with USD 83,450: two digits transposed. At a 4.5% duty rate, the importer overpaid USD 2,025 in duty on the USD 45,000 difference, plus merchandise processing fee on it.

Found in June 2026. ACE shows a scheduled liquidation date of 27 November 2026. Fifteen days before that is 12 November; 300 days from entry is 8 November. The earlier date wins, so the PSC must be filed by 8 November 2026. A PSC correcting the value leads to a refund.

Found in December 2026, after liquidation on 27 November. PSC is no longer available. The liquidation adopted the transposed value, so the route is a protest, due 180 days after liquidation: by 26 May 2027.

Found while reviewing the supplier's files, with the same transposition on fourteen other entries, some overstated and some understated. The understatements mean duty was underpaid, so this is no longer a refund problem. The importer should talk to counsel about a prior disclosure covering all the affected entries, and about how the ones still unliquidated should be corrected alongside it.

The first two outcomes are routine desk work. The third is not, and the most useful thing a broker can do there is recognise it early.

Who decides, and when to call counsel

The importer of record owns the entry and the decision to correct it. The broker usually spots the error, files the PSC or protest on the importer's behalf, and keeps the record of what was changed and why.

Bring in a customs attorney when:

• the error underpaid duty on more than one entry;
• the error is in how value, origin or classification was decided, not in how a number was keyed;
• CBP has already asked questions about the entries in question; or
• a protest has been denied.

None of those is a sign that someone has done something wrong. They are the points where the correction becomes a legal decision.

The cheapest correction is the one you never file

Every PSC starts with a value that went in wrong the first time. For value and quantity errors, the cause is often a shipment packet that disagreed with itself: an invoice and a packing list giving different figures, and the entry built from the wrong one. Catching that before transmission takes far less time than any of the three routes above. Here's how to triage an invoice and packing list that don't match.