Surety Bond: Complete Guide to Types, Costs & Requirements (2026)

The Miller Act and Little Miller Acts

The Federal Miller Act (40 U.S.C. §§ 3131–3134)

Enacted in 1935, the Miller Act is the federal law requiring surety bonds on all U.S. government construction contracts exceeding $150,000. It requires three bonds:

1. Bid Bond — Posted at the time of bidding.
2. Performance Bond — Protects the government if the contractor fails to complete the project.
3. Payment Bond — Protects subcontractors and suppliers who have no direct contract with the federal government.

For projects between $30,000 and $150,000, the contracting officer has discretion to require payment protection in other forms.

Little Miller Acts (State Equivalents)

Every U.S. state has enacted its own version of the Miller Act — commonly called “Little Miller Acts” — which impose bonding requirements on state and local public construction projects. The thresholds and requirements vary significantly by state:

Note: Thresholds are approximate and subject to change. Always verify current requirements with your state’s licensing board or procuring agency.

Private project owners are not bound by Miller Act requirements but frequently include bonding requirements in their contracts, especially on larger projects.

Unique and Interesting Facts About Surety Bonds

The surety bond industry is older, bigger, and more technically sophisticated than most people realize.

📊 Market Scale

The U.S. surety bond market was valued at $23.5 billion in 2025 and is projected to reach $33.1 billion by 2032, growing at a 5.06% CAGR. Infrastructure investment, digital underwriting automation, and expanding state licensing requirements are the primary growth drivers.

📈 Loss Ratios at a 5-Year High

As of September 2024, the direct loss ratio for the surety industry reached 24.5% — up from 22.3% at end-2023 and the highest in five years. The primary drivers: subcontractor defaults, rising material costs, and supply chain disruptions that strained contractor cash flows on active projects. Underwriters are responding by tightening credit thresholds and increasing their scrutiny of WIP schedules.

🏛️ The SBA Program Is Larger Than Most Realize

In fiscal year 2024, the SBA Surety Bond Guarantee Program guaranteed 11,092 bonds covering more than $10 billion in contract value — a record. The program covers bonds on federal projects up to $14 million, with the SBA absorbing 80–90% of the surety’s loss on approved bonds.

💳 Credit Score Is the #1 Rate Driver

For bonds under $100,000, a single credit score pulls 60–80% of the underwriting weight. Moving from a 599 to a 620 can cut your premium rate in half. Moving from 649 to 720 can reduce it by 70–80%. No other improvement a principal can make has as large an impact on bond cost as credit score improvement.

🔢 The Rule of Thumb: Ten Times Working Capital

An old surety underwriting guideline states that a contractor can support bonded work equal to ten times their working capital. A contractor with $500,000 in working capital (current assets minus current liabilities) can theoretically support $5 million in bonded backlog. This is not a universal formula, but it’s a useful benchmark for understanding how sureties think about capacity.

🏗️ The Largest Single Surety Bond in U.S. History

The largest surety bonds ever issued in the U.S. have been appeal bonds in major litigation. In 2003, Philip Morris was required to post a $12 billion appeal bond before a $10.1 billion judgment could be appealed in Illinois — an amount that briefly threatened the company’s ability to continue operating. The Illinois legislature subsequently passed a law capping appeal bonds at $2.5 billion. Several other states followed.

🌍 Surety Bonds Are Uniquely American

Surety bonds in their modern form — as distinct from insurance — are primarily a U.S. and Canadian phenomenon. Most other countries use bank guarantees (letters of credit issued by commercial banks) for the same purposes. The U.S. surety model is considered more efficient because surety companies perform deep pre-qualification of principals, theoretically preventing problems before they occur rather than simply compensating for them afterward.

⚖️ The General Agreement of Indemnity Can Bind Your Spouse

When you sign a GAI for a business bond, sureties routinely require personal guarantees from all owners with 10% or more ownership — and in many cases, from their spouses. This is not arbitrary. Courts have sometimes found that a principal can transfer assets to a non-signing spouse to avoid GAI enforcement. Spousal signatures close that gap.

🏦 Sureties Are Required to Be Treasury-Listed

Not every insurance company can issue surety bonds on federal projects. The U.S. Treasury Department maintains a Circular 570 list of acceptable sureties for federal projects — companies that have demonstrated sufficient capital and operational controls. Swiftbonds works exclusively with Treasury-listed and A.M. Best A-rated carriers.

🔍 Digital Underwriting Is Transforming Small-Bond Markets

Historically, even small bonds required manual review and paper applications. Today, algorithmic underwriting platforms can approve bonds under $50,000 in under three minutes using credit bureau data, business registration records, and license history. This has dramatically reduced the cost and friction of the license bond market.

Default Predictors

Firm size, leverage, receivables robust indicators; surety bonds’ endogenous variables (e.g., project match) boost default forecasting vs. ratings alone.​

A Brief History of Surety Bonds

Surety bonds are among the oldest financial instruments in recorded history.

Ancient origins. The earliest written record of surety arrangements appears in the Code of Hammurabi (c. 1750 BCE), which established rules for guarantors in commercial contracts. Ancient Roman law recognized the fidejussor — a personal guarantor who could be held liable for another party’s debts.

Medieval development. Merchant guilds in medieval Europe formalized surety-like arrangements for trade, requiring guarantors before goods could be shipped across borders or credit could be extended. English common law codified the rights and obligations of sureties by the 17th century.

The modern era begins in 1894. The American Surety Company, founded in New York in 1884, is widely credited as the first corporate surety in the United States. Before corporate sureties existed, individuals — friends, family members, business associates — served as personal guarantors. The shift to corporate suretyship introduced professional underwriting and financial accountability.

The Miller Act (1935). Following decades of disputes over unpaid laborers and suppliers on federal projects, Congress passed the Miller Act, requiring performance and payment bonds on all federal construction projects over a defined threshold. The Act established the foundational framework for contract bonding that remains in use today.

The SBA program (1970s–present). The SBA Surety Bond Guarantee Program was established to expand access to bonding for small and minority-owned businesses historically shut out of the commercial surety market.

The digital revolution (2000s–present). Online applications, algorithmic underwriting, digital bond delivery, and electronic obligee filing have transformed the industry. What once took days of paperwork and courier delivery now happens in hours — or minutes.