How to fill out a shipper's letter of instruction (SLI), step by step

A freight forwarder once filed a client's export with the value pulled from a draft quote instead of the final commercial invoice, because the shipper's letter of instruction left the value field blank and the forwarder "filled in what they had." The shipment left fine. Three months later the exporter, not the forwarder, got the penalty notice from Census for an inaccurate EEI filing.

That is the thing to understand about the shipper's letter of instruction: it is the document where you hand your shipment to someone else, but the legal responsibility stays with you. Fill it out carelessly and you are not saving time, you are authorizing a stranger to make mistakes in your name. This guide walks through every field so that does not happen.

What is a shipper's letter of instruction, and when do you need one?

A shipper's letter of instruction (SLI) is a document the exporter gives to its freight forwarder that does two jobs at once:

1. It instructs. It tells the forwarder how to route, book, and handle the shipment, and it hands over the shipment data they need: parties, commodity, Schedule B number, value, weight.
2. It authorizes. It grants the forwarder limited power of attorney to prepare export documents and to file your Electronic Export Information (EEI) in the Automated Export System (AES) on your behalf.

You need one any time a forwarder is moving an international shipment for you and you want them to file the EEI or book transport in your name. If a separate, standing power of attorney is already on file with that forwarder, the SLI rides on top of it as the per-shipment instruction sheet. If no POA exists, the signature on the SLI is what gives the forwarder authority to act.

You are the USPPI, the U.S. Principal Party in Interest: the person in the United States who receives the primary benefit of the export. That label matters because it follows you into the next section.

SLI vs commercial invoice vs EEI: keep the three straight

These three get conflated constantly, and the confusion is where errors breed. They are not the same document and they do not have the same reader.

The SLI sits in the middle. It pulls data from the commercial invoice and the packing list, and it feeds that data into the EEI. If the three disagree, the disagreement surfaces as a customs hold or a Census penalty, and it surfaces against you.

How to fill out a shipper's letter of instruction, field by field

Formats vary between forwarders, but nearly every SLI carries the same blocks. Work top to bottom with your commercial invoice and packing list open beside you, because the golden rule here is the same one that governs the whole export document set: every shared field must match.

The parties

1. USPPI (exporter). Your full legal company name and address, with the 5-digit ZIP in its own field, plus your EIN (tax ID), a contact name, a 10-digit phone number with no parentheses or dashes, and an email. The EIN is how AES identifies you; get a digit wrong and the filing rejects.

2. Ultimate consignee. The party abroad who actually receives the goods. Name and full address, character for character as it appears on the commercial invoice and bill of lading. Note the consignee type (direct consumer, government entity, reseller, or other), because AES asks for it.

3. Intermediate consignee. Only if the goods pass through an intermediary (for example a forwarder's overseas agent) before reaching the ultimate consignee. Leave blank if there is none, do not invent one.

4. Forwarding agent. The freight forwarder's name and address. This is who you are instructing.

Routing and transport

5. Transport details. Mode of transport (vessel, air, truck, rail), the U.S. port of export, the country of ultimate destination, and the carrier if known. Note whether the shipment moves direct or is consolidated with other freight, and flag any special handling (hazardous, temperature, oversize). Your Incoterm determines how far your responsibility runs, so it belongs here too.

The commodity lines

Up to six commodity lines usually fit on one SLI; use a continuation page if you have more.

6. Description, Schedule B, value, weight. For each line: a plain-English description, the Schedule B or HS number, the quantity and unit of measure, the value, and the net weight. The Schedule B number is the export classification that extends your six-digit HS code to ten digits; if you are not solid on the base code, start with what an HS code is. The value here must be the commercial invoice value, not a quote, not an estimate.

7. Domestic or foreign origin (D/F). Mark whether each line was produced domestically or is foreign goods being re-exported. Report foreign-origin goods separately from domestic.

8. Export control information. The ECCN or license number, or a license exception symbol, or "NLR" (No License Required) for ordinary commercial goods that fall under EAR99. If your goods are controlled (defense articles, dual-use technology), this field is not optional and the wrong entry here is the most serious mistake on the form.

The EEI and authorization block

9. EEI / AES details. Indicate whether EEI is required. As a rule of thumb, you must file when the value per Schedule B number exceeds 2,500 dollars, or whenever an export license is required, regardless of value. See the official EEI requirements for the edge cases. If the shipment is exempt, cite the exemption (commonly the de minimis exemption for shipments at or under 2,500 dollars). Once the forwarder files, the returned ITN goes back onto this document and the bill of lading.

10. Routed or standard export transaction. Mark which one applies. In a standard transaction you control the movement and authorize the filing. In a routed transaction the foreign buyer controls it and authorizes their own forwarder. This single checkbox decides who is responsible for the EEI, so it is worth a hard look. There is a short section on it below.

11. Authorization and signature. The block that grants the forwarder authority to act as your agent and to file EEI on your behalf, signed and dated by an authorized representative of the USPPI, with name and title. An unsigned SLI gives the forwarder nothing. Read what you are signing: it is a power of attorney, narrow but real.

Routed vs standard export transaction: the field that trips people up

Most small exporters run standard transactions: you sell, you arrange (or your forwarder arranges on your instruction) the export, and the EEI gets filed under your authorization. You are the USPPI and you carry the filing responsibility.

A routed transaction is different. The foreign buyer (the FPPI, foreign principal party in interest) takes control of the movement and hires a U.S. agent to export the goods, and that agent files the EEI. You are still the USPPI and you must still provide your data, but the filing duty shifts to the buyer's agent. Two things go wrong here constantly: exporters mark "routed" because the buyer chose the forwarder (choosing the forwarder is not the same as controlling the movement), and shipments leave with each side assuming the other filed. If you are unsure which one you are in, ask who has the contract of carriage. That answers it.

The 6 mistakes that put fines on the exporter

1. Leaving the value or Schedule B blank and letting the forwarder guess. This is the original sin. You are liable for the EEI data even when they type it.
2. A value that does not match the commercial invoice. AES value, invoice value, and the duty base should be one number. Reissue the invoice and you must update the SLI.
3. Marking routed vs standard wrong. The most consequential checkbox on the form, and the one most often ticked on autopilot.
4. Consignee name drift. "Damascus Trading LLC" on the SLI, "Damascus Trading L.L.C." on the bill of lading. A document checker treats that as a discrepancy.
5. Wrong or missing export control entry. Defaulting to "NLR" on goods that actually need a license is not a typo, it is a violation.
6. Signing the authorization without reading it, or not signing at all. One hands over more authority than you meant to; the other leaves your forwarder unable to file.

Five of those six are not knowledge failures. They are consistency failures between the SLI and the rest of the document set, or sign-off failures. That is precisely the class of error ExportDocsHub is built to remove: the SLI, commercial invoice, packing list, and certificate of origin are all generated from one shipment record, so the consignee, value, weight, and Schedule B are entered once and cannot drift apart on the way to your forwarder.

Fill the blocks in order, make every shared field match the invoice, get the routed-or-standard call right, and read the authorization before you sign it. Do that and the SLI stops being the document that quietly transfers your mistakes to a third party, and goes back to being what it should be: a clean set of instructions that gets your shipment out the door.

---

Further reading

• Export documents checklist: what every small exporter needs
• How to fill out a certificate of origin, step by step
• What is an HS code? How to find yours