Customs Entry Liquidation: The One-Year Clock, Extensions, and Notices

Key Points

• Liquidation is CBP's final, official computation of duties owed on an import entry. It either confirms the amount deposited at entry or adjusts it up or down.
• Under 19 U.S.C. 1504, CBP must liquidate an entry within one year of the date of entry, unless it extends the period.
• CBP may extend the liquidation period in one-year increments, but the total time from entry to liquidation cannot exceed four years in all.
• If CBP neither liquidates nor extends within the required window, the entry is "deemed liquidated" at the rate and amount asserted by the importer, by operation of law.
• In ACE, liquidation is typically scheduled approximately 314 days after the date of entry, giving CBP time to process before the statutory deadline expires.

On this page

1. What customs entry liquidation is and why it matters
2. The one-year statutory clock and how it starts
3. The ACE scheduled liquidation at 314 days
4. Extensions: rules, limits, and notice requirements
5. Deemed liquidation when deadlines are missed
6. The bulletin notice of liquidation
7. What liquidation means for refunds and additional duty bills
8. What importers should do
9. Key references

Customs entry liquidation is the final step in the lifecycle of an import entry. CBP reviews the entry, calculates the correct duties, fees, and taxes, and issues a formal determination. If the amount differs from what the importer deposited at the time of entry, CBP either issues a bill for additional duties or authorizes a refund. Until liquidation occurs, no duty amount is truly final.

The links in this article go to the primary documents: the statutes, regulations, and official CBP pages themselves. Read the source.

What customs entry liquidation is and why it matters

When goods are imported into the United States, the importer (or their broker) files an entry and deposits estimated duties based on the declared classification, value, and applicable duty rates. That deposit is just an estimate. Liquidation is the moment CBP makes the legal determination of what was actually owed.

Liquidation can result in three outcomes:

• No change: CBP confirms the estimated duties were correct. The entry closes at the deposited amount.
• Underpayment: CBP issues a bill for additional duties. The importer must pay the difference, plus interest if applicable.
• Overpayment: CBP authorizes a refund of excess duties deposited. Interest may also be paid to the importer on the overpayment.

Because liquidation sets the legally binding duty amount, it also starts the clock on the importer's right to protest CBP's decision. Missing the protest window after liquidation means losing that avenue for recourse. The regulations governing liquidation are found in 19 CFR Part 159.

The one-year statutory clock and how it starts

The statutory authority for liquidation timelines is 19 U.S.C. 1504. The statute establishes that CBP must liquidate an entry within one year of the date of entry. For consumption entries, the clock typically begins on the date the entry summary is filed and accepted by CBP, though the specific trigger can vary by entry type. Importers and brokers should confirm the applicable date for each entry in ACE.

The one-year rule is not a target, it is a legal requirement. If CBP does not act within that window, specific consequences follow automatically under the statute (see the deemed liquidation section below).

The ACE scheduled liquidation at 314 days

Within CBP's Automated Commercial Environment (ACE), entries are typically placed on a liquidation schedule approximately 314 days after the date of entry. This internal scheduling gives CBP and its partner government agencies time to review the entry, process any requests for information, and complete any pending actions, all before the one-year statutory deadline arrives.

Importers and brokers can monitor scheduled liquidation dates through ACE. An entry appearing on the 314-day schedule is on track for timely liquidation. If a review is still pending close to that date, CBP may extend the liquidation rather than let the clock expire. If you are tracking entry data at scale, understanding how ACE schedules liquidation is essential. For context on how ACE data is used in CBP's review processes, see our related article on what an importer risk assessment from ACE data looks like.

Extensions: rules, limits, and notice requirements

CBP may extend the liquidation period when it needs more time to complete its review. Common reasons include:

• Pending antidumping or countervailing duty (AD/CVD) reviews by the Department of Commerce
• Outstanding requests for information, such as a CBP Form 28 (Request for Information) or Form 29 (Notice of Action)
• Unresolved classification or valuation questions
• Pending protests or court proceedings that affect the applicable rate

How extensions work under 19 U.S.C. 1504

Under 19 U.S.C. 1504, CBP may extend the liquidation period in increments of up to one year at a time. However, the total period from the date of entry to final liquidation cannot exceed four years in all. That means a maximum of one initial year plus three annual extensions, for a total of four years.

CBP is required to provide notice to the importer of record when it extends a liquidation. These extension notices are issued through the bulletin notice system and are visible in ACE. Importers should not assume silence from CBP means liquidation has occurred. Always verify the status in ACE or through your broker.

Voluntary requests for extension

In certain circumstances, the importer of record may request that CBP extend the liquidation of an entry. This is less common but can be strategically relevant when the importer is awaiting a ruling, a refund claim, or a resolution of a related legal matter. Procedures for such requests are governed by 19 CFR Part 159.

Deemed liquidation when deadlines are missed

If CBP fails to liquidate an entry or issue a valid extension notice within the applicable statutory period, the entry is "deemed liquidated" by operation of law under 19 U.S.C. 1504. Deemed liquidation occurs at the rate and amount asserted by the importer in the entry, meaning the estimated duties deposited at the time of filing become the final, legally binding amount.

Deemed liquidation can work in the importer's favor if CBP would otherwise have assessed higher duties. But it can also cut off the importer's ability to receive a refund if CBP would have liquidated at a lower rate. Deemed liquidation is a specific legal event with its own procedures for recognition and protest. Because it has significant implications, it merits its own detailed treatment; this article links to that discussion rather than reproducing it.

The bulletin notice of liquidation

Once an entry is liquidated, CBP issues a formal bulletin notice of liquidation. Historically, these notices were posted physically at the port of entry. Today, in the ACE environment, bulletin notices of liquidation are issued electronically and are accessible through ACE, typically to the importer of record and the filer of record.

The bulletin notice is legally significant for two reasons:

• It starts the protest clock. An importer who disagrees with the liquidated amount generally has 180 days from the date of the bulletin notice to file a protest with CBP. Missing this deadline forfeits the protest right for that entry.
• It confirms the final duty amount. The notice will show whether the entry liquidated as entered, with additional duties billed, or with a refund authorized.

Importers and brokers should have a process for monitoring bulletin notices in ACE promptly, rather than waiting for a paper statement or broker notification. A missed notice can mean a missed protest deadline. Because bulletin notices are also their own distinct topic, this article treats them at the overview level and links to the dedicated term page for full procedural detail.

What liquidation means for refunds and additional duty bills

Refunds after liquidation

When liquidation results in a finding that the importer overpaid duties, CBP authorizes a refund. The refund is typically applied as a credit against the importer's continuous bond account or paid directly, depending on the payment method used. Interest on overpayments may be paid to the importer, calculated from the date of overpayment under rules in 19 CFR Part 159.

Importers pursuing duty refunds through post-entry amendments, protests, or other mechanisms must coordinate those filings with the liquidation timeline. A refund claim filed after liquidation generally must be pursued through the protest process within the 180-day window.

Additional duty bills after liquidation

When liquidation results in a finding of underpayment, CBP issues a bill for the additional duties owed. Interest accrues on the underpayment from the date of liquidation. Failure to pay timely can result in referral for collection. Importers who believe a liquidation bill is incorrect must file a protest within the applicable deadline; paying a bill does not waive the right to protest, but the protest must still be timely filed.

For entries subject to antidumping or countervailing duties, the final liquidated amount can differ substantially from the estimated cash deposit rate, particularly when Commerce issues a final results order after the initial entry. This is one of the most common sources of surprise duty bills in trade compliance.

What importers should do

• Monitor ACE for scheduled liquidation dates and bulletin notices. Do not rely solely on broker notifications. Set internal calendars for each entry's one-year anniversary and check ACE for extension notices or liquidation status well before that date.
• Track the 180-day protest window from every bulletin notice. Assign responsibility within your team or with your broker to review each liquidation and decide promptly whether to protest. The deadline does not extend for administrative convenience.
• Flag entries subject to AD/CVD cash deposits for extended liquidation risk. These entries are routinely held open for the duration of Commerce's administrative review cycle, often approaching the four-year statutory maximum. Budget and bond accordingly.
• Review extension notices immediately upon receipt. An extension notice signals CBP has an unresolved issue with the entry. Use the notice as a prompt to assess whether additional documentation, a ruling request, or legal review is warranted before liquidation occurs.

Key references

• 19 U.S.C. 1504: The statute governing liquidation timing, extensions (up to four years total), and deemed liquidation.
• 19 CFR Part 159: CBP's regulations implementing liquidation procedures, refunds, and interest.
• CBP.gov: Official CBP guidance, CSMS messages, and ACE resources on entry processing and liquidation.
• Harmonized Tariff Schedule (hts.usitc.gov): The official HTS for verifying classification and applicable duty rates at the time of entry.
• Federal Register (federalregister.gov): Source for Commerce antidumping and countervailing duty final results orders that affect liquidation of AD/CVD entries.