What Is the HMF Rate? Harbor Maintenance Fee Payers and Penalties

The Harbor Maintenance Fee rate is 0.125 percent of the cargo’s value, a flat ad valorem charge collected by U.S. Customs and Border Protection on commercial shipments loaded or unloaded at federally maintained U.S. ports.¹ Written in decimal form as .00125, the rate is set by the Internal Revenue Code and has not changed since the fee was created by the Water Resources Development Act of 1986.² It applies to imports, certain domestic waterborne shipments, Foreign Trade Zone admissions, and passengers on commercial vessels. Exports are not subject to the fee.

Because the charge is a percentage, the dollar amount scales with cargo value. A $100,000 shipment generates a $125 fee. A $10 million shipment generates $12,500. Unlike customs duties, which shift by product classification and country of origin, the HMF applies the same percentage across all qualifying cargo.³

How the Value Base Is Calculated

The rate is only useful when you apply it to the right number. The valuation rule depends on the shipment type:

For imports, the fee is based on the CBP-appraised value of the merchandise under 19 U.S.C. 1401a, the same method used for calculating customs duties.⁴
For domestic waterborne shipments, the fee is based on the value shown in standard commercial documentation. If that documentation isn’t available, the value is calculated as if the cargo were imported merchandise.³
For passengers, the fee is based on the actual fare paid, or the prevailing charge for comparable service if no fare was charged.³

For imports, the appraised value typically reflects the transaction price of the goods. International freight and insurance are generally separate from that appraised value, so keeping invoices that clearly distinguish product cost from shipping and insurance costs helps avoid overpaying.

What’s Exempt

Not every shipment crossing a qualifying port owes the fee. The statute and regulation carve out several categories:

Exports. The Supreme Court held in 1998 that applying the HMF to outbound cargo violates the Constitution’s Export Clause, and the statute now reflects a blanket export exemption.⁵⁶
Cargo shipped between the mainland and Alaska, Hawaii, or any U.S. possession for consumption there, and cargo moving within a single state or territory. Crude oil shipped from Alaska does not qualify.⁴
Cargo owned by the federal government or any of its agencies.⁴
Bunker fuel consumed by the vessel, ship’s stores, and equipment necessary to the ship’s operation. Bunker fuel is only exempt when it is fueling the ship; if it is being carried between ports as cargo on a barge, it is subject to the fee for that transit.⁷
Fish and other aquatic life caught at sea and not previously landed on shore.⁶
Ferries on a regular daily schedule carrying passengers and their vehicles between U.S. points or between the U.S. and a neighboring country.⁴
Cargo entered in bond and transported directly to a foreign destination without entering U.S. commerce, with limited exceptions for cargo bound for Canada or Mexico.⁴
Cargo owned or financed by nonprofit organizations and certified by CBP as humanitarian or development assistance shipped overseas.⁴
Cargo moving on vessels whose fuel is already subject to the Inland Waterway Fuel Tax. The term “port” does not include inland waterways, so no double taxation applies.⁴

Small-Shipment and Quarterly Thresholds

Small shipments get a pass. Imported cargo that qualifies for informal entry procedures is not subject to the fee. Domestic shipments valued at $1,000 or less are exempt. And a quarterly threshold applies: if the total value of all your assessed shipments for the entire quarter is $10,000 or less, no payment is required for that quarter.⁴

Two anti-double-counting rules also apply. Moving cargo within a single port does not trigger the fee, and cargo already assessed at loading is not charged again when the same vessel unloads it.⁴

Who Owes the Fee

Liability depends on the direction the cargo is moving. For imports, the importer pays. For domestic waterborne movements between U.S. ports, the shipper paying the freight is responsible.² For passengers on commercial vessels, the vessel operator owes the fee. For cargo admitted into a Foreign Trade Zone, the party bringing the merchandise into the zone is liable, and the fee is triggered when the cargo is unloaded from the vessel, not when it later leaves the zone.³

When and How to Pay

The HMF is paid quarterly, not per shipment. Payment must reach CBP within 31 days after the close of each calendar quarter, so the deadlines fall around May 1, July 31, October 31, and January 31, following quarters ending March 31, June 30, September 30, and December 31.³

The filing document is CBP Form 349, the Harbor Maintenance Fee Quarterly Summary Report.⁸ It requires an IRS Employer Identification Number or Social Security Number tying the payment to the correct entity, along with the total assessed value of shipments for the quarter.⁹

Electronic payment through Pay.gov is the standard method and gives immediate confirmation. A check with the completed form can also be mailed to:

U.S. Customs and Border Protection
Revenue Division
8899 E. 56th Street, Mail Stop 203-J
Indianapolis, IN 46249¹⁰

To correct a prior filing, request a refund, or make a supplemental payment, use CBP Form 350, the amended quarterly summary report. Common triggers include calculation errors, duplicate payments, misapplied exemptions, and omitted shipments.¹¹ Federal record-retention rules require businesses to keep harbor maintenance records for five years so CBP can verify past filings during an audit.

Penalties for Late or Missing Payments

Missing the 31-day deadline is not something CBP overlooks. A party that fails to pay the fee and file the summary report on time faces liquidated damages equal to the amount assessed for late filing of an entry summary. Importers may also be held liable under their basic importation and entry bond.³

Interest also accrues on overdue accounts. For the quarter beginning April 1, 2026, the underpayment interest rate is 6 percent for both corporations and non-corporations.¹² The rate adjusts quarterly, so checking the Federal Register each quarter is worthwhile if any balance is outstanding. Relief from penalties or liquidated damages can be requested through the petition process in 19 CFR Parts 171 and 172.³

1
U.S. Customs and Border Protection. What is The Harbor Maintenance Fee (HMF)?
2
Office of the Law Revision Counsel. 26 USC 4461 – Imposition of Tax
3
eCFR. 19 CFR 24.24 – Harbor Maintenance Fee
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eCFR. 19 CFR 24.24 – Harbor Maintenance Fee
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Legal Information Institute. United States v United States Shoe Corp
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Office of the Law Revision Counsel. 26 USC 4462 – Definitions and Special Rules
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U.S. Customs and Border Protection. CROSS Ruling H086062
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U.S. Customs and Border Protection. CBP Form 349 – Harbor Maintenance Fee Quarterly Summary Report
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U.S. Customs and Border Protection. CBP Form 349 – Harbor Maintenance Fee Quarterly Summary Report
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U.S. Customs and Border Protection. Payment Mailing Addresses
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U.S. Customs and Border Protection. CBP Form 350 – Harbor Maintenance Fee Amended Quarterly Summary Report
12
Federal Register. Quarterly IRS Interest Rates Used in Calculating Interest on Overdue Accounts and Refunds of Customs Duties