USPS will invoice the sender for duty the buyer never paid

Most of the regulatory news an import desk reads is about the container. This one is about the envelope, and it changes who ends up paying for it.

On 19 October 2026 the Postal Service published an interim final rule, effective that day, revising the International Mail Manual “to update mailer responsibilities with respect to customs requirements and to establish procedures for the payment, or reimbursement, of any customs charges that are assessed, including after the purchase of postage.”

The operative part is a new section, IMM 424, “Unpaid Destination Customs Charges”. It is short, and it is worth reading in the order the Postal Service wrote it.

The bill can arrive after the item did

If any relevant party in the destination country (for example, the customs authority, postal operator (or its agent), customs broker, or customs representative) seeks to collect duties, taxes, or import fees from the mailer or the Postal Service (or their representatives), and such amounts have not been paid in full, the Postal Service (or its representative) will send an invoice to the mailer for such amounts.

That is 424.1. Nothing in it is conditioned on the item’s fate. 424.2 removes the obvious hope:

The mailer is not relieved of its obligation to pay for duties, taxes, and import fees, regardless of whether the item is delivered, lost, damaged, or returned.

So a sample that went to a customer in Rotterdam in September, was delivered, and was signed for, can produce a payable in November. The shipment file is closed. The costing is done. The invoice is new.

You pay first and argue afterwards, and not with USPS

The same section, 424.2, in full:

The mailer must pay the Postal Service (or its representative) the entire amount due in accordance with the invoice terms, even if the mailer disputes the assessment.

And 424.5 says who you may argue with:

The mailer may dispute with the Postal Service only accounting errors related to Postal Service invoicing by seeking a refund.

The rate, the valuation, the classification and the foreign operator’s handling fee all “must be addressed directly to such party without involvement from the Postal Service”. That is a dispute conducted in another country’s language, against another country’s customs authority, over a parcel you no longer have, by a desk that has no local agent because the consignment went by post precisely so that it would not need one.

424.3 states the position plainly: USPS “is not responsible for the accuracy of duties, taxes, import fees, or other charges calculated by entities in the destination country”.

And it earns interest

If payment is not received by the Postal Service (or its representative) on or before the due date as set forth in the invoice, interest on the unpaid amounts will accrue at a rate of 6 percent per annum until the amounts are paid in full.

Plus the Postal Service’s collection costs, “to the extent permitted by applicable law”, and the option to treat the unpaid amounts as revenue deficiencies under DMM 607.3.0.

Six per cent is not the point. The point is that the clock starts on a due date printed on an invoice nobody was expecting, for a shipment that left the building weeks earlier, and that nothing in the rule sets a floor below which the invoice is not raised.

Why now: the EU closed de minimis in July

The preamble says where this came from, and it is not a US decision:

As of July 1, 2026, the European Commission eliminated the de minimis exemption for most low-value goods destined to the European Union customs territory. In addition, the European Commission established a new hierarchical system for determining who is responsible for paying applicable duties, taxes, and import fees for such low-value goods.

European postal operators responded in three ways the rule names. Some require certain items to be sent on an approved delivered duty paid basis, with the duty paid by the mailer up front. Some “have adopted consequences such as fees and other charges that apply in certain situations, such as if inaccurate customs information is provided by the mailer”. And where an item goes duty unpaid and the money cannot be recovered from the addressee, the destination operator “may seek to collect unpaid amounts from the mailer”.

Section 424 is the plumbing that passes that third case back down the chain to you. If your destination requires a duty-paid solution, IMM 112 now says you “must send the mailpiece on a delivered duty paid basis and must ensure that all applicable duties, taxes, and import fees … are timely paid”. Which rule of Incoterms your sales contract names does not change that obligation; it only decides who you can recover from afterwards.

The documentation half, which is the part a desk controls

The other half of the rule is the one an import–export desk will recognise immediately. IMM 112, as revised, makes it the mailer’s job

to determine what documents and information (e.g., commercial invoice, certificate of origin, power of attorney, health certificate, license, authorization for goods subject to quarantine such as plant, animal, or food products, product identification numbers, etc.) are required in the destination country, and to provide all such documents and information in a manner that is complete, accurate, and timely.

And the consequence of not doing so: “the mailpiece may be returned or confiscated and the mailer may be subject to additional charges.”

That is the same list the desk already assembles for a container: the commercial invoice, the certificate of origin, the health or phytosanitary certificate. It is now applied to a channel most desks treat as outside the document process altogether. Postal consignments usually go out from sales or from the warehouse, with the customs form filled in by whoever is holding the box. From today an error on that form has a price, and the price arrives later.

What this does to a desk’s numbers

Two things, and neither is large on its own.

The first is a payable with no purchase order behind it. On the reference desk this site uses, payment tracking already runs 10 to 15 minutes per container, and that is for amounts the desk knew were coming. A duty invoice raised against a parcel sent two months ago matches nothing: not a shipment file, not a supplier, not an accrual. It arrives as a line in a Postal Service statement and has to be traced backwards to a mailpiece before anyone can say whether it is right, and the only dispute available is an accounting one.

The second is that the obligation does not expire with the item. Lost, damaged, returned: the duty is still owed. A returns process that treats a refused parcel as a cost already written off will under-accrue by whatever the destination assessed on the way in.

If you ship samples, spare parts or small consignments into the EU by post, three things are worth doing this week. Find out whether your destination operators require a duty-paid solution, because IMM 112 now makes that your obligation rather than a service option. Make sure whoever fills in the customs form is working from the same document set the container shipments use, since the rule’s own list is that list. And give the duty invoice somewhere to land: a payment calendar that carries dates nobody told you about is the difference between a traced payable and a 6% accrual.

Comments on the rule close on 18 November 2026, by post to the manager of Product Classification or by email with the subject line “Customs Requirements and Payment Procedures”. The rule is in force in the meantime.