Does a commercial invoice need to be signed under UCP 600?
No. A commercial invoice does NOT need to be signed under Article 18 of UCP 600 unless the letter of credit explicitly requires a signature.
Read on for the official rules, banking practice, examples, and tips to avoid LC payment delays and discrepancy charges.
 |
A Common but Costly Question
A USD 500,000 LC payment was delayed because the commercial invoice was unsigned—even though the LC did not require a signature. Was the bank justified in rejecting it?
To answer this, we must distinguish between what the rules say and how banks apply them in practice.
Unsigned Commercial Invoice in LC — Why It Is NOT a Discrepancy under UCP 600
One of the most common — and costly — points of friction in documentary credit transactions is the unsigned commercial invoice.
While the rules appear clear, banking practice often tells a more cautious story. This article explains the official ICC rule position, why banks still reject unsigned invoices, and what exporters can do to eliminate unnecessary risk.
The Official Rule Position
UCP 600 – Commercial Invoice Requirements
UCP 600 Article 18(c) states clearly:
A commercial invoice need not be signed unless the credit requires it.
Conclusion:
If a Letter of Credit (LC) is silent regarding a signature, an issuing or confirming bank may not reject a commercial invoice solely because it is unsigned.
ISBP 821 (2023) – Practical Interpretation
ISBP 821 Paragraph A28(a) reinforces this position by confirming that:
-
A commercial invoice does not require a signature unless:
-
The LC expressly requires it, or
-
The document format itself implies that a signature is intended
-
From a purely technical rules perspective, an unsigned invoice is therefore acceptable when the LC is silent.
Why Banks Still Reject Unsigned Invoices
Despite the clarity of UCP 600 Article 18, rejections still occur — usually relying on UCP 600 Article 14(d), as interpreted through ISBP.
Article 14(d) – Data Consistency and Completeness
Article 14(d) requires that:
Data in a document must not conflict with data in that document, any other required document, or the credit.
While the article does not explicitly mention signatures, banks apply it to assess whether a document appears incomplete.
ISBP 821 Paragraph A28(b): The Critical Detail
ISBP 821 A28(b) provides crucial guidance:
-
If a document contains a blank space clearly intended for a signature, stamp, or seal, the document may appear incomplete
This is where problems arise in practice.
The High-Risk Scenario
Invoice Format:
Contains a pre-printed field such as:
-
“Authorized Signature”
-
“Seller’s Seal & Signature”
Exporter Action:
Leaves the field blank because the LC does not require a signature.
Bank Reaction:
Rejects the invoice on the grounds that it appears incomplete, citing:
-
UCP 600 Article 14(d), and
-
ISBP 821 Paragraph A28(b)
This is not a contradiction of UCP 600, but a conservative strict-compliance assessment based on document appearance.
The Safest Actions for Exporters (Commercial Invoice Practices)
This table outlines three key actions exporters can take regarding commercial invoices to minimize discrepancies and ensure smooth international trade payment, particularly when dealing with Letters of Credit (LCs).
| Priority | Action | Why It Works |
| 1 (Safest) | Sign the invoice | A signature normally does not create a discrepancy and removes all doubt regarding the authenticity and finality of the document. |
| 2 (Best Practice) | Remove unused signature boxes | Eliminates any implication that a signature was intended, preventing an appearance-of-incompleteness discrepancy. |
| 3 (Proactive) | Insert an LC clause: "Unsigned commercial invoice acceptable" | Neutralizes any arguments based on the "appearance-of-incompleteness" and explicitly confirms that a signature is not required under the Letter of Credit terms. |
Frequently Asked Questions
1. Does UCP 600 require commercial invoices to be signed?
No.
UCP 600 Article 18(c) does not require a signature unless the LC demands one.
2. What does ISBP 821 say about unsigned invoices?
ISBP 821 confirms that a signature is not required unless required by the LC or implied by the document format.
3. Can a blank signature line cause a discrepancy?
Yes.
A blank signature field may cause the document to appear incomplete under Article 14(d), as explained by ISBP 821 A28(b).
4. What if the LC is silent?
Technically, the invoice may be unsigned.
Practically, exporters should still sign the invoice or remove signature fields to avoid rejection.
5. Are digital or electronic signatures acceptable?
Yes, provided that:
-
The LC allows electronic presentation and is subject to eUCP, or
-
For paper presentations, the electronic signature is clearly identifiable and accepted by the bank’s practice
6. Is it acceptable to sign an invoice even if not required?
Yes.
An additional signature normally does not create non-compliance and often prevents disputes.
7. Can an exporter dispute rejection of an unsigned invoice?
Yes — by citing:
-
UCP 600 Article 18(c), and
-
ISBP 821 Paragraph A28
However, disputes often lead to costly delays, even when the exporter is technically correct.
8. Which ISBP version is current?
ISBP 821 (2023) — replacing ISBP 745 (2013).
9. Can banks apply internal policy over UCP?
Banks must comply with UCP 600 and ISBP, but may apply conservative interpretations within Article 14(d). This is common market practice.
10. What is the safest approach overall?
Absolute clarity at the LC drafting stage, combined with clean, unambiguous document formats.
Digital & Electronic Signatures: Practical Guidance
-
UCP 600 Article 17 addresses originals, while eUCP governs electronic records
-
ISBP 821 Paragraph A9 confirms that electronic records fall under eUCP when applicable
Key takeaway:
-
If the LC is subject to eUCP, electronic invoices and digital signatures must be accepted
-
For paper presentations, confirm bank acceptance of electronic signatures in advance
Real-World Banking Lesson
In a recent case, a Turkish exporter’s documents were rejected due to an unsigned invoice under an LC that did not require a signature.
Although the discrepancy was later waived after citing ISBP guidance, the exporter incurred USD 15,000 in storage and demurrage costs due to delays.
Lesson:
Even when you are technically right, delays can still be expensive.
Practical Compliance Summary Table
Here is the table summarizing practical actions related to signatures on documents under a Letter of Credit (LC):
| Issue | Recommended Action |
| LC silent on signature (e.g., on the invoice) | Sign invoice or remove signature box entirely if no signature is needed. |
| Signature explicitly required (by the LC or UCP 600 article/sub-article) | Sign strictly as required (e.g., if a document requires counter signature or certifying signature). |
| Blank signature field (i.e., a box or line for a signature is present but not filled) | Remove or obliterate the blank signature box/field, or sign it, to avoid discrepancy. |
| Digital signature | Confirm the issuing/confirming bank's acceptance, or utilize it in transactions governed by eUCP (electronic presentation rules). |
Final Conclusion
Under UCP 600 and ISBP 821, a commercial invoice does not require a signature unless:
-
The LC expressly requires it, or
-
The document format implies that a signature was intended
However, because documentary credits operate on strict compliance, banks may still reject invoices that appear incomplete.
Best Practice
Align LC wording, document format, and bank expectations.
If a signature is unnecessary, say so clearly in the LC — or remove signature fields entirely.
In trade finance, clarity prevents cost.
Plan for Document Preparation:
If your LC documents are rejected due to minor issues like an unsigned invoice, review the rejection reason carefully, refer to UCP 600 Article 18 and ISBP 821 A21, contact the issuing bank for clarification or reconsideration, discuss with your buyer if an LC amendment is needed, correct and resubmit the documents promptly, and communicate potential delays to all parties involved to manage expectations. For new exporters, following a structured approach is essential — see our How to Prepare LC Documents: Step-by-Step Guide and Templates for New Exporters for practical templates and guidance to avoid such costly mistakes.
 |
