What Is a Bank Letter of Credit and How It Works

A bank letter of credit is a written promise from a bank to pay a seller a set amount once the seller presents documents proving shipment that match the credit’s terms exactly. It replaces the buyer’s credit risk with the bank’s, which is why it anchors so much international trade between parties who have no history and operate under different legal systems. Industry estimates suggest that between 60 and 75 percent of document presentations are rejected on first submission because of paperwork errors, so the details matter from the moment the deal is drafted.

How the Transaction Moves From Order to Payment

The sequence is predictable once you’ve seen it. The buyer and seller sign a sales contract that calls for payment by letter of credit. The buyer then applies to their own bank, called the issuing bank, with every detail of the deal: the seller’s identity, what’s being shipped, the credit amount, and the exact documents the seller will have to produce as proof of shipment.

The issuing bank checks the buyer’s credit, takes collateral or draws on an existing credit line, and opens the credit. Most are transmitted electronically between banks and routed to an advising bank in the seller’s country, which authenticates the credit and hands it to the seller.¹

The seller reads the terms, confirms they can meet them, manufactures and ships the goods, then gathers every document the credit requires. That package goes to a nominated bank for examination. If the documents match the credit terms, the bank pays. The documents then travel back up the chain to the issuing bank, which collects from the buyer and releases the documents so the buyer can claim the goods from the carrier at the destination port.²

Who the Parties Are

A standard credit involves at least four parties, sometimes five or six.

The applicant is the buyer. They ask for the credit and are ultimately responsible for reimbursing the issuing bank.
The beneficiary is the seller, entitled to payment if their documents comply.
The issuing bank is the buyer’s bank. It carries the legal obligation to pay against complying documents.
The advising bank sits in the seller’s country, authenticates the credit, and delivers it. It takes on no payment obligation by doing so.³
The nominated bank is authorized by the issuing bank to actually pay, accept drafts, or negotiate documents. Often it is the same institution as the advising bank.
A confirming bank is optional. It adds its own independent payment guarantee on top of the issuing bank’s. Sellers ask for confirmation when the issuing bank sits in a country with political or economic instability.

Why Banks Only Look at the Documents

The single most important rule in letter of credit law: banks deal in documents, not goods. The bank examining a presentation will never open a container, test product quality, or verify what’s inside the boxes. Its only job is to read the documents and decide whether they match the credit terms on their face.³

This is the independence principle. The bank’s payment obligation sits apart from the underlying sales contract. If the buyer and seller are fighting over product quality, that dispute does not touch the bank’s duty to pay against compliant documents. If the documents don’t match, the bank refuses payment even when the goods are perfect.

The examination standard is strict compliance. Under the Uniform Customs and Practice for Documentary Credits (UCP 600), the international rulebook published by the International Chamber of Commerce, a bank must pay only when the documents constitute a “complying presentation.” There is no room for documents that are “almost the same” or “will do just as well.”³ A misspelled company name, a weight that doesn’t line up across two documents, or a missing signature can all trigger a refusal. That strictness is what makes the instrument trustworthy; everyone knows the rule, and nobody gets to decide what “close enough” means.

In the United States, letters of credit are also governed domestically by Article 5 of the Uniform Commercial Code, adopted in every state. The UCC reinforces the same point: an issuer must honor a presentation that appears on its face to strictly comply, and must dishonor one that does not.⁴

The Types You’ll Encounter

Commercial vs. Standby

A commercial (or documentary) credit is the primary payment method for a specific trade transaction. The seller expects to draw on it by presenting shipping documents after each shipment. A standby credit sits in the background and is only drawn upon if the buyer fails to perform some other obligation, such as defaulting on a loan or failing to pay an invoice. It’s a backup, not the intended payment channel.

Sight vs. Usance

A sight credit triggers payment as soon as the bank determines the documents comply, usually within a few business days of presentation. A usance credit (also called a deferred payment credit) delays payment to a future date specified in the credit, often 60 or 90 days after shipment, giving the buyer trade credit before payment comes due.⁵ Sellers who don’t want to wait can sometimes arrange discounting, where a bank pays them early at a small reduction and collects the full amount at maturity.

Irrevocable by Default

Under UCP 600, every letter of credit is irrevocable by default, even when the document doesn’t say so.³ Once issued, neither the buyer nor the issuing bank can cancel or change its terms without the seller’s written consent. The prior version of the rules allowed revocable credits; UCP 600 eliminated them.

Transferable and Revolving

A transferable credit lets the seller transfer part or all of the credit to a third party, usually the actual manufacturer or supplier. Trading companies and brokers use this when they source from a supplier but don’t want to tie up capital paying them before the end buyer pays. A revolving credit automatically reinstates its available amount after each drawing, without a formal amendment, which suits buyers and sellers running repeat shipments of the same goods.

When It’s Worth the Cost

Letters of credit are not cheap or simple. They carry bank fees, require collateral, and demand precise paperwork. They earn their place when transaction risk justifies the cost. A first-time deal with an unknown buyer is the classic case: no track record, so the credit substitutes a bank’s guarantee for a stranger’s promise. Large-value orders amplify the risk enough that the fees become reasonable. Trades involving countries with political instability or weak banking systems are another strong fit, especially when paired with a confirming bank in a stable jurisdiction. Deals where the buyer needs extended payment terms work well too, because the seller holds a bank-backed promise of future payment rather than just an invoice and hope.

For established relationships, many exporters move to open account terms, sometimes backed by trade credit insurance. Open account is cheaper, but it shifts all non-payment risk to the seller. Documentary collections sit in the middle: banks handle the document exchange without guaranteeing payment. The letter of credit remains the strongest protection available to a seller who can’t afford to lose the shipment value.

What the Buyer Puts Into the Application

The buyer completes a detailed application with the issuing bank. Every detail becomes a binding term the seller must match precisely. Key items include the beneficiary’s full legal name and address, the exact credit amount and currency, a precise description of the goods, the specific documents required (bill of lading, commercial invoice, insurance certificate, inspection or origin certificates, and so on), the latest shipment date, and the final expiry date for presenting documents.

The goods description deserves particular care. If the credit says “500 units of stainless steel grade 304 pipe fittings” and the seller’s invoice says “500 pcs SS304 pipe fittings,” that mismatch alone can trigger a refusal. The description in the application should mirror the sales contract word for word.

Collateral and Fees

The issuing bank needs assurance it can be reimbursed. For buyers with an established banking relationship and strong credit, the bank draws on the existing credit line. For small businesses or first-time applicants, standard practice often requires cash collateral equal to 100 percent of the credit amount, freezing that cash in a margin account until the transaction closes. The SBA’s Export Express and Export Working Capital programs can reduce that requirement to 25 percent for qualifying small businesses seeking standby credits through participating lenders.⁶

Issuance fees typically run between 0.5 and 1.5 percent of the credit’s face value per year. A $200,000 credit at one percent costs the buyer $2,000 in issuance fees alone. Confirmation, when the seller asks for it, adds another 0.25 to 2 percent depending on the perceived risk of the issuing bank’s country. Amendments, document examination, and courier services carry their own charges. These costs usually fall on the buyer, though the sales contract can allocate fees differently.

Presenting Documents and Getting Paid

After shipping, the seller gathers every document the credit lists and presents the complete package to the nominated bank before the credit expires. Timing is rigid. The credit specifies a latest shipment date and an expiry date for document presentation, and many also set a maximum number of days after shipment within which documents must be presented. The UCP 600 default is 21 calendar days.

The nominated bank then examines the documents against the credit terms. Under UCP 600, the bank has a maximum of five banking days after the day of presentation to decide whether the documents comply.³ It reads each document on its face against the credit’s requirements. It does not investigate whether the statements in the documents are true.

If the documents comply, the bank honors the credit, paying immediately on a sight credit or committing to a future date on a usance credit. The documents then travel to the issuing bank, which reimburses itself from the buyer and releases them so the buyer can collect the goods.

Where These Deals Break

Common Discrepancies

Most presentations fail the first time, and the errors are often painfully minor. The usual suspects:

The invoice doesn’t mirror the credit’s goods description word for word.
The goods shipped after the latest shipment date in the credit.
Documents arrived at the bank after the expiry date or after the maximum days allowed following shipment.
The bill of lading has the wrong consignee, a missing onboard notation, no signature, or a different port than the credit specifies.
The invoice, packing list, and bill of lading show different numbers for weight, volume, or unit count.
A required certificate, inspection report, or insurance document is simply missing.
Insurance covers the wrong amount, wrong currency, wrong risks, or was issued after the shipment date.

Every one of these is avoidable. Read the credit the moment it arrives, flag anything you can’t comply with before you ship, and have a second set of eyes cross-check every document against the credit before presenting to the bank.

The Waiver Process

When the bank finds discrepancies, it must send a single refusal notice to the presenter no later than the close of the fifth banking day after presentation. That notice has to list every discrepancy and state what the bank intends to do with the documents.³

The seller then has two paths: fix the documents and re-present them if the credit hasn’t expired, or ask the buyer to waive the discrepancies. In a waiver, the issuing bank contacts the buyer, who decides whether to accept the documents despite the errors. Even if the buyer agrees, the issuing bank still has the final say; the buyer’s waiver does not automatically oblige the bank to accept.⁷ In practice most banks follow the buyer’s instruction, but the distinction matters legally.

Buyers sometimes use discrepancies as leverage. If the market price for the goods has dropped since the order was placed, a buyer may decline to waive a discrepancy that they would have ignored a month earlier. The seller is then stuck with goods in transit and no payment. That is exactly why first-time accuracy is so critical.

The Fraud Exception

The independence principle has one major carve-out. Under UCC Section 5-109, if a required document is forged or materially fraudulent, or if honoring the presentation would facilitate a material fraud by the seller against the buyer or the bank, the issuing bank may refuse to pay even when the documents appear to comply on their face.⁴

This exception is deliberately narrow. A buyer who received lower-quality goods than expected cannot invoke it. The fraud must be material, and courts have set a high bar. A buyer seeking a court injunction to block payment before the bank honors the credit must show they are more likely than not to prove forgery or material fraud, and that the person demanding payment doesn’t qualify as a protected party who gave value in good faith without knowledge of the fraud.⁴ A plain breach of contract, such as shipping goods that don’t meet specifications, is not fraud. The buyer’s remedy there is a separate lawsuit against the seller, not an attempt to freeze the bank’s payment.

Expired Credits

If the seller misses the expiry date, the credit ceases to exist. The issuing bank has no obligation to examine or pay against a late presentation, and the normal UCP 600 rules about examination periods and refusal notices no longer apply. A confirming bank, if there is one, is equally released. The seller’s only recourse at that point is to negotiate directly with the buyer for payment outside the credit framework, which is the exact position the credit was designed to prevent. Managing the expiry date is entirely the seller’s responsibility, and missing it is one of the most expensive mistakes in trade finance.

1
Swift. Category 7 – Documentary Credits and Guarantees – Message Reference Guide
2
International Trade Administration. Letters of Credit
3
International Chamber of Commerce (ICC). Set of Guidance Papers on Recommended Principles and Usages around UCP 600 Rules
4
Legal Information Institute (Cornell Law School). UCC 5-109 – Fraud and Forgery
5
Export-Import Bank of the United States. Faster Payments and Letters of Credit
6
U.S. Small Business Administration. Providing Standby Letters of Credit to Your Client is Easy with SBA
7
International Chamber of Commerce. Examination of Documents, Waiver of Discrepancies and Notice