Surety Bond vs Letter of Credit: Which Should You Use?
Both surety bonds and letters of credit guarantee your performance on a contract. But they work in fundamentally different ways, and picking the wrong one can cost you tens of thousands of dollars in unnecessary fees and frozen credit. Here is what you need to know before you decide.
Table of Contents
Quick Comparison: Surety Bond vs Letter of Credit
Structure
Bond: 3-party: principal, surety, obligee
LC: 2-party: applicant and bank (beneficiary draws)
Bonds add a layer of investigation before payment
Cost
Bond: 1-15% annual premium, no collateral for qualified applicants
LC: 1-10% annual fee PLUS ties up full credit line
Bonds are usually cheaper overall
Credit Line Impact
Bond: Does not reduce available credit
LC: Reduces available credit by full LC amount
Bonds preserve your borrowing capacity
Claim Process
Bond: Surety investigates before paying
LC: Bank pays on first demand (no investigation)
Bonds protect principals from frivolous claims
Collateral
Bond: None required for most qualified contractors
LC: Typically 100% cash collateral or credit reduction
Bonds free up working capital
Best For
Bond: Construction, licensing, statutory requirements
LC: International trade, quick-draw liquidity guarantees
Different tools for different jobs
How Each One Works
Surety Bonds: Three Parties, One Guarantee
A surety bond creates a three-party relationship. You (the principal) purchase a bond from a surety company, and that bond guarantees your performance to a third party (the obligee, usually a project owner or government agency). If you fail to perform, the obligee files a claim. The surety investigates the claim, and if it is valid, pays out — then comes after you for reimbursement.
This is the standard instrument for performance bonds and bid bonds on public construction projects. The surety acts as a gatekeeper: they prequalify you before issuing the bond, and they investigate claims before paying them.
Letters of Credit: Two Parties, Instant Payment
A letter of credit is a bank obligation. You ask your bank to issue an LC in favor of a beneficiary. If the beneficiary presents documents that comply with the LC terms, the bank pays. Period. The bank does not investigate whether the underlying claim is legitimate — it only checks whether the paperwork matches.
This “pay first, argue later” structure makes LCs popular in international trade where parties do not know each other. But it also means you have no protection against a draw you believe is unjustified. You would need to pursue the beneficiary separately in court to recover funds.
The Key Difference
With a surety bond, someone investigates your side of the story before any money changes hands. With a letter of credit, the bank pays first and you sort it out afterward. For contractors, this distinction matters more than the cost difference. Learn more about how bonds differ from other financial instruments in our bond vs insurance comparison.
Federal Contract Rules (FAR 28.204-3)
The Federal Acquisition Regulation explicitly allows irrevocable letters of credit as an alternative to surety bonds on federal contracts. But the rules are specific.
LC Requirements Under FAR 28.204-3
- Irrevocable: The LC cannot be canceled or amended without the government's consent
- Federally insured institution: The issuing bank must be federally insured and carry at least an investment-grade rating
- One LC per bond: Each bond being replaced needs its own separate letter of credit
- Over $5M threshold: LCs exceeding $5 million require a confirming institution that handles at least $25 million in annual LC business
Most contractors working on projects covered by the Miller Act still use surety bonds because the LC requirements are demanding and the credit line impact is substantial. But if your company has deep banking relationships and strong cash reserves, an LC can work.
Cost Comparison
On paper, the fee percentages look similar. In practice, letters of credit are much more expensive because of what they do to your balance sheet.
Surety Bond Costs
Use our bond cost calculator to estimate your premium.
Letter of Credit Costs
Total effective cost is significantly higher than the stated fee
Real Example: $500,000 Performance Bond
As a surety bond:
Premium: $2,500-$15,000/year. No collateral. Full credit line available for equipment, materials, and payroll.
As a letter of credit:
Fee: $5,000-$50,000/year. Plus $500,000 frozen on your credit line. Plus $20,000-$25,000/year in opportunity cost on that frozen capital.
Credit Line Impact
This is the single biggest practical difference, and it is why most contractors prefer bonds.
How LCs Eat Your Credit Line
When your bank issues an LC, it reduces your available credit by the full LC amount. If you have a $2 million credit line and issue a $500,000 LC, you now have $1.5 million available for everything else — equipment loans, operating lines, vehicle financing, all of it.
Run three projects simultaneously with LC-backed guarantees and you could exhaust your entire credit facility. That means turning down new work or taking on additional debt at higher rates.
Bonds Leave Your Credit Intact
A surety bond does not appear on your balance sheet as a liability. It does not reduce your available credit. You can bond multiple projects simultaneously without any impact on your borrowing capacity.
A contractor with a $5 million bonding line can pursue five $1 million projects at once while keeping their full bank credit line available for operations. Get a quote to see what bonding capacity you qualify for.
What Happens When a Claim Is Filed
Surety Bond Claim
1. Claim filed — The obligee notifies the surety of an alleged default.
2. Investigation — The surety investigates both sides. This takes 30-90 days for complex construction claims.
3. Decision — The surety can deny invalid claims, negotiate a resolution, arrange project completion, or pay the obligee.
4. Recovery — If the surety pays, it pursues the principal for full reimbursement under the indemnity agreement.
You get due process before anyone gets paid.
Letter of Credit Draw
1. Draw request — The beneficiary presents complying documents to the bank.
2. Document check — The bank verifies the documents match the LC terms. This takes 1-5 business days.
3. Payment — If documents comply, the bank pays. No investigation into whether the claim is legitimate.
4. Reimbursement — The bank debits your account. If you dispute the draw, you sue the beneficiary yourself.
Money leaves first, questions come later.
When to Use Each
Choose a Surety Bond When...
- You need performance or payment bonds for construction
- The project is domestic (US public or private work)
- You want to preserve your credit line for operations
- You need protection against frivolous claims
- You are bidding multiple projects at once
- State or federal law specifically requires a surety bond
Choose a Letter of Credit When...
- The contract is international and parties are unfamiliar
- The beneficiary specifically requires an LC (common overseas)
- You cannot qualify for a surety bond
- Quick liquidity for the beneficiary is the priority
- The transaction is trade-based (import/export), not construction
- You have excess credit capacity you are not using
For Federal Construction: Bonds Are the Default
The Miller Act requires performance and payment bonds on federal projects over $150,000. While FAR 28.204-3 allows LCs as an alternative, over 95% of federal contractors use surety bonds because the credit line math does not work any other way at scale.
Frequently Asked Questions
Q: Can I use a letter of credit instead of a surety bond on a federal project?
A: Yes. FAR 28.204-3 allows irrevocable letters of credit as an alternative to surety bonds on federal contracts. The LC must come from a federally insured financial institution with at least an investment-grade rating, and you need one LC per bond replaced.
Q: Why do most contractors choose bonds over letters of credit?
A: Bonds do not tie up your credit line. A $500,000 performance bond costs roughly $2,500-$15,000 per year in premium without reducing your borrowing capacity. A $500,000 LC would freeze that entire amount on your credit line, limiting your ability to finance equipment, payroll, and materials.
Q: What happens if there is a claim on a surety bond versus a letter of credit?
A: With a surety bond, the surety investigates the claim before paying anything. Invalid claims get denied. With an LC, the bank pays on first demand as long as the draw documents comply with the LC terms. The applicant has to sort out disputes after the money is already gone.
Q: Do letters of credit cost less than surety bonds?
A: The fee percentage can look similar (1-10% for LCs vs 1-15% for bonds), but LCs also require you to set aside cash collateral or absorb a credit line reduction equal to the full LC amount. When you factor in opportunity cost, bonds are typically 2-5 times cheaper for the same coverage.
Q: Are there size limits on letters of credit for federal contracts?
A: Yes. Under FAR 28.204-3, any LC exceeding $5 million must include a confirming institution that does at least $25 million per year in LC business. This requirement exists because the government wants certainty that the issuing bank can honor large draws.
Q: Can a letter of credit help if I cannot qualify for a surety bond?
A: It can, but it is expensive. If your financials or credit history prevent bond approval, an LC gives you an alternative path to bid federal work. However, you will need strong banking relationships and enough available credit to cover the full LC amount. The SBA bond guarantee program may be a better option, backing bonds up to $14 million on federal contracts.
Related Reading
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