CBP does not call your factory. It sends the letter to you, the importer of record, and asks you to produce the documents. The documents sit in a factory in Guangdong, in a filing cabinet, in Chinese, owned by a company with no legal exposure in the United States and no reason to hand them over quickly.
Reasonable care is your obligation, not your supplier's — but the evidence that proves it isn't in your hands. It's in theirs. When the letter arrives, the clock is already running and you're asking a stranger, under deadline, for the thing you should have collected months ago.
Here are the ten things CBP will ask you to produce. Get them from your supplier now, while they still want your next order.
Most importers can't answer this. The name on the invoice is a trading company. The goods were made by a factory that trading company sub-contracts to — sometimes three factories, depending on who was cheapest that week.
CBP doesn't care about your commercial relationship. It cares about the manufacturer. You need the business licence of the entity that physically produced the goods — legal name in Chinese, unified social credit code, registered address, scope of business. Not a letterhead. The licence.
If your supplier won't show you the licence of the actual production facility, you don't have a supply chain. You have a phone number.
Origin isn't decided at the loading dock. It's decided upstream — at the mill, the smelter, the yarn spinner, the resin producer.
CBP wants proof of raw material origin: purchase records between your factory and its own suppliers — the tier you've never spoken to and probably can't name — plus a manufacturer's affidavit naming the entity and the specific place each material was mined, smelted, spun or grown.
Your factory has this. It doesn't want to give it to you, because it reveals its own cost base. That's a negotiation, not an impossibility — and far easier to win before you have a problem than during a detention.
Classification drives your duty rate, your AD/CVD exposure, and your enforcement risk. It rests on what the product is actually made of and how — not on what the invoice calls it. CBP asks you for this. Your factory is the only place the real answer exists.
A bill of materials mapped to the tariff classification is the document that connects the two. Ask for it by country, not by supplier nickname: where was the fabric woven, the resin polymerised, the component moulded. Most Chinese factories have never been asked in that format. They have a production sheet, in Chinese, written for the floor, not for customs.
Back it with what the floor can actually show: mill certificates, material lab reports, and a manufacturing process flowchart — cut, mould, assemble, finish — that matches what you're claiming happened. Translating a production sheet into a defensible BOM is work. Do it once, before entry, and it holds for every shipment after.
Largely, no.
CBP doesn't accept generic certificates as proof of compliance. Self-issued documents from a supplier — the signed declaration, the compliance letter, the certificate with the company chop — carry little weight, because the party with the incentive to lie wrote them.
What carries weight is traceable, verifiable documentation: government-issued licences, transaction records, third-party verification, physical evidence tied to a date and a place.
A supplier affidavit isn't nothing. But it's the weakest document in your file, and if it's the only one, you don't have a file.
No.
Under UFLPA there's a rebuttable presumption against goods from Xinjiang. But CBP looks upstream, not just at your factory's postcode. A plant in Zhejiang buying cotton, polysilicon or aluminium from a Xinjiang-linked supplier is exposed — and so are you.
Geography is the first question, not the last. The answer that matters is the supply map: who supplies your supplier, and where they buy — traced with transport and logistics records showing where the raw material actually moved from, not where the paperwork says it started.
You do.
Antidumping and countervailing duties are the importer's liability, not the supplier's. Rates can exceed 300 per cent — the government's own July 2026 guide puts some cases above 600 — and are often applied retroactively, after the goods are sold and the margin is spent.
Your supplier knows whether the product sits in a covered scope. Your supplier also knows you probably won't ask. Ask — in writing, in Chinese, in the contract — and make the answer a warranty with a consequence attached.
Every article of foreign origin must be marked in a conspicuous place, as legibly, indelibly and permanently as the article permits, with the English name of the country of origin.
Three places this fails. The mark must give the English country name — "Made in China" — not Chinese characters, not a city, not a supplier logo. The exceptions are narrower than importers assume. And "we'll add it at packing" is where the whole thing quietly collapses.
Get the marking method from the factory in writing before production — laser etch, mould-in, stamp, or label — not just a photo after the fact. A method that can be swapped at packing is not a method CBP will find convincing. Ask for a photograph of the marking on a real production unit and on the retail packaging, before the container is sealed. Not on the sample. On production.
This is the hardest item on the list to get your hands on, and the one most likely to end the conversation with your supplier.
Worker records, wage payment and output per worker, recruitment practices and fee receipts, dormitory logs, and a grievance mechanism workers can actually use — that's what forced-labour enforcement turns on. A factory that's never been audited on labour will treat the request as an accusation.
It lands very differently from a Chinese-speaking person sitting in the office than as an email from a buyer in Ohio. That's not a sales line. It's just true.
A CF-28 is CBP asking you to prove what you already declared. It isn't an accusation. It's a deadline — thirty days on most China entries, running from CBP's date, not the day you opened the email.
The problem is never the letter. The problem is that the evidence is in a Chinese factory, the factory is on holiday, the person who knows the answer left the company, and nobody there understands why any of this matters.
Everything on this list exists to make that week boring. Assemble it while the relationship is good — a supplier facing a request from a buyer with an open order is a very different supplier from one facing a request about a shipment from last year.
If your supplier sells you DDP and arranges the broker, you've inherited two problems. You can't see what was declared — undervaluation and misclassification are common in those channels — and you have no entry records to substantiate anything when CBP asks.
CBP penalties follow the goods and the beneficial owner. That's you, whatever the paperwork says.
Insist on being the importer of record. At minimum, demand the entry summary and supporting documents for every shipment. If your supplier resists that, ask yourself why.
This is what lives inside the factory. Your classification memo, your customs bond, your power of attorney, your IPR recordation, your Form 5106 — those live with your broker and your counsel, and we don't touch them. We go to the building for the other half: the licence, the mill, the wires, the worker records, the floor.
Every item on this list is a document that exists, today, inside a building in China. None of it can be produced from a desk in the United States. None of it arrives by email because you asked politely.
We go to the building. We read the licence. We photograph the line. We write the contract in Chinese, under Chinese law, with the correct entity and the correct chop, so the obligation to hand these documents over is a term your supplier agreed to — not a favour you're asking for.