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 specified amount once the seller ships the goods and presents documents that exactly match the terms of the credit before its deadline. It substitutes the bank’s credit for the buyer’s, which is why it remains the standard payment tool when a buyer and seller in different countries have no history of trust and no shared legal system to fall back on. The mechanics are strict, and industry estimates suggest 60 to 75 percent of document presentations are rejected on first submission because of paperwork errors, so understanding how the instrument actually functions is not optional for anyone using one.

How the Transaction Moves From Start to Finish

The sequence is predictable. The buyer and seller negotiate a sales contract that names the letter of credit as the payment method. The buyer then applies to their own bank, called the issuing bank, and provides the transaction details: the seller’s identity, what’s shipping, the credit amount, and the documents the seller must produce as proof of shipment.

The issuing bank checks the buyer’s creditworthiness, takes collateral or draws on the buyer’s credit line, and opens the credit. It transmits the credit to an advising bank in the seller’s country, which authenticates it and passes it to the seller.¹

Once the seller has reviewed the terms and confirmed they can comply, they manufacture and ship the goods. After shipment, they gather every document the credit calls for, typically a bill of lading, commercial invoice, packing list, and insurance certificate, and present the package to a nominated bank for examination. If the documents match the credit’s terms exactly, the bank pays. The documents then travel back through the banking chain to the issuing bank, which collects reimbursement from the buyer and releases the documents so the buyer can claim the goods from the carrier.²

Who Is Involved

A standard transaction has four core parties and sometimes two more, depending on how the risk is structured.

The applicant is the buyer. They request the credit and are ultimately responsible for reimbursing the issuing bank.
The beneficiary is the seller. They are entitled to payment once they present documents that match the terms.
The issuing bank is the buyer’s bank. It opens the credit and carries the legal obligation to pay against compliant documents.
The advising bank sits in the seller’s country, authenticates the credit, and delivers it to the seller. It takes on no payment obligation by doing so.³
The nominated bank is authorized by the issuing bank to pay, accept drafts, or negotiate documents. It is often 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. If the issuing bank fails to pay for any reason, the confirming bank steps in. Sellers ask for confirmation when the issuing bank sits in a country with political or economic instability.³

Why Banks Look Only at Documents

The governing principle is simple: banks deal in documents, not goods. A bank examining a presentation will never open a shipping container, test product quality, or verify that what’s inside the boxes matches the description. Its job is to read the documents and decide whether they match the credit’s terms on their face.³

This is the independence principle. The bank’s payment obligation is completely separate from the underlying sales contract. If the buyer and seller are arguing over product quality, that dispute has no effect on the bank’s duty to pay against compliant documents. And if the documents don’t match, the bank refuses payment even when the goods are perfect.

The examination standard is called 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.” Documents that are “almost the same” or “will do just as well” do not qualify.³ A misspelled company name, a weight that doesn’t line up across two documents, or a missing signature can trigger a refusal. The strictness is what makes the credit trustworthy. Everyone knows the rules, and no one gets to decide whether something is close enough.

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 principle: an issuer must honor a presentation that appears on its face to strictly comply, and must dishonor one that does not.⁴ For international deals, UCP 600 typically governs the documentary examination while the UCC provides the domestic legal framework.

The Main Types You’ll Encounter

Commercial vs. Standby

A commercial (or documentary) letter of credit is the primary payment method for a specific trade transaction. The seller expects to draw on it by presenting shipping documents after every shipment. A standby letter of credit works more like an insurance policy. It 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. The standby is a backup, not the intended payment channel.

Sight vs. Usance

A sight credit triggers payment as soon as the bank determines the documents comply. The seller usually receives funds within a few business days of a compliant presentation. A usance credit, sometimes called a deferred payment credit, delays payment to a future date specified in the credit, such as 60 or 90 days after shipment. That gives the buyer a window of trade credit before payment is due.⁵

Irrevocable by Default

Under UCP 600, every letter of credit is irrevocable by default, even if the document doesn’t explicitly 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 previous version of the rules allowed revocable credits, but UCP 600 eliminated them.

Transferable and Revolving

A transferable credit lets the seller transfer part or all of the credit to another party, usually the actual manufacturer or supplier. This is common when the seller is a trading company or broker who sources goods from a third party but doesn’t want to tie up capital paying the supplier directly. A revolving credit automatically reinstates its available amount after each drawing without a formal amendment, which suits buyers and sellers who trade the same goods repeatedly.

When It’s Worth Using One

Letters of credit are not the cheapest or simplest way to pay. They carry bank fees, require collateral, and demand precise paperwork. They earn their place when the transaction risk justifies the cost.

First-time trade relationships are the classic case. You have no history with the counterparty, and the credit gives you a bank’s guarantee instead of a stranger’s promise. Large orders amplify the risk enough that the fees become a reasonable cost of doing business. 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. Transactions where the buyer needs extended payment terms also work well, because a usance credit gives the seller a bank-backed promise of future payment rather than just an invoice and hope.

For established relationships with reliable buyers, many exporters transition to open account terms, where the buyer simply pays after receiving the goods, sometimes backed by trade credit insurance. Open account is cheaper and simpler, but it shifts the non-payment risk to the seller. Documentary collections offer a middle ground, with banks handling the document exchange but no payment guarantee. The letter of credit remains the strongest protection available to a seller who cannot afford to lose the shipment value.

What It Costs and What the Bank Needs From the Buyer

The Application

The buyer completes a detailed application with the issuing bank. Every detail becomes a binding term the seller must match in the document presentation, so precision matters from the start. The key items are the beneficiary’s full legal name and address, the exact credit amount and currency, a precise goods description, the specific documents the seller must present, the latest permissible shipment date, and the expiry date for presentation of documents.

The goods description matters more than most buyers realize. 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 can trigger a refusal. The description in the application should mirror the sales contract exactly.

Collateral

The issuing bank needs assurance that the buyer can reimburse it. For buyers with an established banking relationship and strong credit, the bank draws on the buyer’s existing credit line. For small businesses or first-time applicants, standard practice often requires cash collateral equal to 100 percent of the credit amount, essentially freezing that cash in a margin account until the transaction closes.

Fees

Banks charge an issuance fee that typically runs from 0.5 to 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. If the seller requests confirmation, the confirmation fee adds another 0.25 to 2 percent depending on the perceived risk of the issuing bank’s country. Additional charges accumulate for amendments, document examination, and courier services. The costs generally fall on the buyer, though the sales contract can allocate them differently.

Where Things Go Wrong

Document Discrepancies

This is where most transactions stumble. Most first presentations are rejected for discrepancies, and the errors are often minor. The frequent ones include a goods description that doesn’t mirror the credit word for word, goods shipped after the latest shipment date, documents presented after the expiry date or after the maximum days allowed following shipment (the UCP 600 default is 21 calendar days), bills of lading with the wrong consignee or missing onboard notation, inconsistent weights or quantities across the invoice, packing list, and bill of lading, missing certificates or inspection reports, and insurance that covers the wrong amount, currency, or risks or was issued after the shipment date.

Every one of these is avoidable. Read the credit terms the moment you receive them, flag anything you cannot comply with before you ship, and cross-check every document against the requirements before presenting them to the bank.

Refusal and Waiver

Under UCP 600, the bank has a maximum of five banking days after the day of presentation to examine the documents and decide whether they comply.³ When it finds discrepancies, it must send a single refusal notice by the close of the fifth banking day, listing every discrepancy and stating what it intends to do with the documents.

The seller then has two options: 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 and gives them a window to decide whether to accept the documents despite the errors. If the buyer agrees, the issuing bank still has the final say. The buyer’s waiver does not automatically oblige the bank to accept.⁶ 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 they would have ignored a month earlier. The seller is then stuck with goods in transit and no payment, which is precisely why getting the documents right the first time is 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

The exception is narrow. A buyer who simply received lower-quality goods than expected cannot invoke it. The fraud must be material, and if a buyer wants a court to issue an injunction blocking payment before the bank honors the credit, they 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 An ordinary breach of contract, such as shipping goods that don’t meet the agreed specifications, is not fraud. The buyer’s remedy there is a separate lawsuit against the seller, not an attempt to block the bank’s payment.

Missing the Expiry Date

If the seller fails to present documents before the credit expires, it ceases to exist. The issuing bank has no obligation to examine or pay against a late presentation, and the normal UCP 600 rules about the five-day examination period and formal refusal notices no longer apply. A confirming bank, if there is one, is equally released. The seller’s only recourse then is to negotiate directly with the buyer for payment outside the credit framework, which is exactly the position the credit was designed to prevent. Managing the expiry date is entirely the seller’s responsibility.

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
International Chamber of Commerce. Examination of Documents, Waiver of Discrepancies and Notice