The goods cleared weeks ago. Then someone spots it: the invoice quantity was entered in pieces instead of kilograms, or a Chapter 99 line never made it onto the summary. Customs gives importers a way to fix entry errors after release, and it is called a post summary correction. It is not a free edit window. It has a deadline, a format, and a hard stop at liquidation.
What a PSC can and cannot touch
A post summary correction amends an entry summary that has been filed but not yet liquidated. Value, classification, quantity, and origin claims can be corrected, and additional duty can be tendered with the correction. Importers file PSCs through their broker in ACE, line by line, with the corrected data replacing what was originally transmitted.
What a PSC cannot do is rewind a liquidated entry. Once CBP liquidates, the correction route closes and the remaining tool is a protest under 19 USC 1514, filed within 180 days of liquidation, or a prior disclosure when the error involves a material false statement. Knowing which side of liquidation an entry sits on decides the whole strategy.
The errors that surface late
Quantity unit mismatches lead the list. A supplier invoice in gross weight entered as net weight changes duty on weight based lines and distorts every statistic downstream. Missed assists run second: a mould the buyer paid for separately, never added to the entered value, discovered when finance reconciles tooling invoices at quarter end.
Origin marking errors are slower and uglier. A preference claim entered for goods that only partly qualify does not get cheaper to fix with time. Each of these errors has the same property: the paper trail to prove the correct figure exists somewhere in the company, and the PSC is only as good as that trail.
Filing it properly
The correction states what changed and why, in the remarks, plainly. Vague remarks invite a CF 28 and a file review the importer did not plan on. Supporting documents, the corrected invoice, the calculation, the payment record, stay in the entry folder, because a PSC without evidence behind it is just a second assertion replacing a first one.
Where additional duty is owed, it is tendered with the correction. Where a refund is claimed, expect scrutiny proportional to the amount. Confirm the current PSC filing window and liquidation status with a licensed customs broker before filing, because an entry near liquidation can move while paperwork is being prepared.
The habit that prevents most of them
A ten day post entry check catches nearly all of it. One person, not the broker, compares the 7501 against the commercial invoice, the packing list, and the purchase order for a sample of entries each month, and logs every mismatch. The sample matters more than the size: five entries checked closely teach more than five hundred glanced at.
Importers who run that check file PSCs as routine maintenance. Importers who skip it file protests, disclosures, and explanations. The correction itself is cheap. Finding out late is what costs.
Keep reading
Related guides on this site: Customs Recordkeeping: The Five Year File an Importer Must Be Able to Produce Reasonable Care for Importers: What It Means in Practice, Entry by Entry Answers for teams shipping Shopify orders across borders.
Frequently asked questions
What is a post summary correction?
It is an amendment to an entry summary filed in ACE before liquidation, used to correct value, classification, quantity, or other entry data. Additional duty owed is tendered with the filing. Once an entry liquidates, a PSC is no longer available.
How long do I have to file a PSC?
The correction must reach CBP before the entry liquidates, and liquidation normally happens within about a year of entry unless extended or suspended. Because timing varies by entry, check liquidation status in ACE or with your broker before assuming the window is open.
What if the entry already liquidated with an error?
The usual route is a protest under 19 USC 1514, filed within 180 days of liquidation for decisions protestable under the statute. For material errors involving false statements, a prior disclosure under 19 USC 1592 may also need to be considered with counsel or a broker.
Does filing a PSC trigger an audit?
A single well documented correction is routine and common. Patterns matter more: repeated corrections of the same error suggest a systemic problem, and that pattern, not the individual PSC, is what draws deeper questions.