If you import goods into the United States, there’s a good chance your customs broker has made a mistake on one of your entries. Currency errors, wrong HTS codes, misclassified country of origin — these things happen more often than most importers realize. The question isn’t whether errors happen. It’s whether you catch them in time to fix them.
That’s where a Post Summary Correction comes in.
A PSC is your primary tool for correcting customs entry errors and recovering overpaid duties after the initial clearance window has closed. Most importers don’t know it exists. The ones who do often wait too long to use it. This guide walks through what a PSC actually is, when you need to file one, and how to avoid leaving money on the table.
What is a Post Summary Correction?
A Post Summary Correction (PSC) is a formal self-declaration to U.S. Customs and Border Protection (CBP) that an error was made on a customs entry and needs to be corrected.
Think of it as an amended tax return for your import declaration. When your broker files a customs entry on your behalf, they’re declaring things like country of origin, HTS classification, and invoice value. If any of those fields are wrong — and you catch it after the entry has been finalized — you file a PSC to correct the record.
PSCs are used to fix errors that result in either overpayment or underpayment of duties. If you overpaid, filing a PSC is how you get your money back. If you underpaid, filing a PSC is how you self-correct before CBP finds the error and hits you with penalties.
The important thing to understand: filing a PSC is not admitting fault. It’s acknowledging that the entry needs to be corrected. CBP would much rather you catch your own mistakes than wait for them to find them in an audit.
Why PSCs matter more than they used to
For years, customs entries were relatively straightforward. Tariff rates were stable, classifications were predictable, and the cost of broker errors was manageable. Most importers never thought about auditing their entries, let alone filing corrections.
That’s changed.
The tariff complexity introduced in 2024 and 2025 — IEEPA codes, Section 232 declarations, in-transit exclusions, shifting country-specific rates — made customs entries significantly harder to get right. Entries that used to require one HTS code now require three or four. Brokers are human, and the error rate went up.
At the same time, the cost of those errors increased. A misclassified HTS code that used to cost a few hundred dollars in overpaid duties now costs tens of thousands. A currency error declaring one million Taiwanese dollars as one million U.S. dollars becomes a major overpayment that takes months to recover.
And with hundreds of billions of dollars in IEEPA refunds now flowing back through the system, CBP is auditing more aggressively. They’ve explicitly stated that refunds will be issued “unless compliance issues are found.” If your entries have errors and you request a refund, there’s a good chance CBP will find them.
The window to catch and correct those errors before CBP does? 314 days.
The three windows for correcting customs entries
There are three timelines that matter when correcting a customs entry, and they operate in sequence.
10 business days after customs clearance: the easy correction window
When your shipment clears customs, you have 10 business days to tell your broker to make corrections before the entry is finalized. Within this window, corrections are straightforward — no penalties, no scrutiny, no formal filing required. Your broker just updates the entry.
This is the window you want to use. If you catch an error within 10 days, fixing it is cheap and simple. The problem is that most importers don’t review their entries until weeks or months later, by which time this window has closed.
314 days from the date of import: the PSC window
Once the 10-day window closes and the entry is finalized, you have 314 days from the date of import to file a Post Summary Correction. This is your primary tool for recovering overpaid duties or self-correcting underpayments after the easy window has passed.
Filing a PSC does put that entry on CBP’s radar to some degree — they track the ratio of PSCs to total entries for each importer — but it’s still far better than waiting for CBP to find the error in an audit. Self-correcting shows good faith and avoids penalties.
Refunds from PSCs typically take a few months to process. If you file on day 300, you’re pushing your refund well into the following year. The earlier you file, the sooner you get your money back.
180 days after the PSC window closes: the protest window
If you miss the 314-day PSC window, you have an additional 180 days to file a formal protest with CBP. Protests are more labor-intensive, come with greater scrutiny, and often require legal assistance. This is not where you want to end up.
The math here is important: 314 days + 180 days = 494 days from the date of import. After that, your ability to correct the entry is essentially gone. If you overpaid duties and don’t file within that window, the money stays with the government.
When should you file a PSC?
You should file a PSC whenever you discover an error on a finalized customs entry that resulted in overpaid or underpaid duties — and you’re outside the 10-day correction window but still within the 314-day PSC window.
Here are the most common scenarios where importers file PSCs:
1. You overpaid duties due to broker error
Your broker declared the wrong HTS code, the wrong country of origin, or the wrong currency, and you paid more in duties than you should have. This is the most common reason importers file PSCs, and it’s often where the largest refunds come from.
2. You underpaid duties and want to self-correct before CBP finds it
Your broker made an error that resulted in underpaid duties. If CBP discovers this in an audit, you’ll face penalties of 1.5x to 2.5x the duties owed. Filing a PSC to self-correct avoids those penalties and shows good faith compliance.
3. You’re requesting an IEEPA refund and want to clean up your entries first
If you’re filing for IEEPA tariff refunds, CBP is going to review those entries. If there are errors on the original filings, now is the time to correct them proactively via PSC before CBP flags them.
4. You launched a new product and your broker misclassified the first few shipments
New SKUs are where classification errors happen most often. If you catch the mistake after a few shipments have already cleared, you’ll need to file PSCs on all of them and update the classification going forward.
5. You’re running a customs audit and finding systemic errors
If you’re auditing your broker and discovering recurring errors across multiple entries — wrong origin declarations, repeated HTS mistakes, consistent currency problems — you’ll likely need to file PSCs on all affected entries within the 314-day window.
What you need to file a PSC
Filing a PSC requires the same documentation you used for the original entry, plus the corrected information. Here’s what you’ll need:
- The original entry number and entry summary (CBP Form 7501)
- The commercial invoice and bill of lading for the shipment
- The corrected information (HTS code, country of origin, value, etc.)
- Supporting documentation for the correction (supplier declarations, mill certificates, updated invoices, etc.)
Your customs broker typically handles the actual filing of the PSC. You provide them with the corrected information and supporting documents, and they submit the correction to CBP on your behalf.
If you don’t trust your broker to file the correction accurately — especially if they’re the ones who made the original error — you can work with a different broker or a trade compliance consultant to handle the PSC filing.
What happens after you file a PSC
Once your PSC is filed, CBP reviews the correction and the supporting documentation. If they accept the correction, they’ll issue a refund (if you overpaid) or send a bill for additional duties (if you underpaid).
Refunds typically take 2-4 months to process, though timelines vary depending on CBP’s workload and the complexity of the correction. Large refunds or corrections involving multiple entries may take longer.
If CBP disagrees with your correction or needs additional documentation, they’ll reach out to your broker (or you, if you filed directly) for clarification. This is where having strong supporting documentation matters. If you can’t prove the correction, CBP won’t approve it.
How to avoid needing PSCs in the first place
The best PSC is the one you don’t have to file. Here’s how to catch errors before they become corrections:
Audit entries within the 10-day window
When your broker sends you the customs release forms after clearance, review them immediately. Check country of origin, HTS classification, and declared value against your commercial invoice. If something looks wrong, you still have time to correct it for free.
Flag new SKUs for extra scrutiny
Every time you launch a new product, audit the first few entries closely. Classification errors are most common on new SKUs, and catching them early means you don’t have to file PSCs on dozens of shipments later.
Pull your ACE data and look for anomalies
Your Automated Commercial Environment (ACE) portal has a record of every import declaration from the last five years. Pull that data quarterly and scan for anything unusual — wrong countries, unusual values, unfamiliar HTS codes. These are your early warning signs.
Run parallel test shipments when switching brokers
If you’re considering a new broker, don’t switch entirely at once. Run a few trial shipments in parallel and compare the entries side by side. Check accuracy, response time, and documentation quality before you commit.
Assign ownership to supply chain, not finance
The team that should be auditing entries is supply chain and logistics — not finance. Supply chain has visibility to when shipments clear and can start the audit clock immediately. If audit responsibility drifts to finance, you’ve almost certainly missed the 10-day window.
What to do if you keep finding errors
If you’re regularly filing PSCs because your broker keeps making mistakes, something needs to change.
Before you fire your broker, give them a chance to fix the process. Customs compliance is genuinely harder than it used to be, and your broker’s errors may be a workflow issue rather than a competence issue. Sit down with them, walk through the recurring problems, and see if they can tighten up their quality control.
At the same time, run trial shipments with another broker. Test a few entries, compare accuracy, and evaluate communication and responsiveness. The biggest mistake importers make when switching brokers is going all-or-nothing — firing one immediately and onboarding another without overlap. That transition period is when errors spike. Trial shipments give you a real comparison before you commit.
PSCs as a recovery tool, not just a compliance obligation
Most importers think of PSCs as something you file when you made a mistake and need to fix it. That’s true. But PSCs are also a money recovery tool.
When you run a serious audit on your customs entries, you’ll almost always find overpayments. Broker errors, classification mistakes, currency problems — these things add up. For importers running regular audits, it’s common to recover 10-15% of duties paid through PSC filings.
Across a meaningful import program, that’s real money. And with a 314-day window to file, the opportunity doesn’t last forever.
If you’ve never audited your entries and filed corrections, start with last month’s shipments and work backwards. Sort by the largest duty payments first — those are where the refund opportunity is greatest. Check country of origin, HTS classification, and declared value on each entry. Flag anything that looks wrong and file PSCs while you still have time.
The worst outcome isn’t filing a PSC and discovering you were right all along. The worst outcome is missing the window and leaving tens of thousands of dollars on the table.
This post was developed in partnership with Graham Anderson, Co-Founder of Importal, an AI-native licensed customs brokerage.
