Surety Bonding
How the surety relationship, underwriting, and bonding limits work in depth
Construction bonding is a three-party financial guarantee used to protect project owners, subcontractors, and suppliers from contractor default and nonpayment. A surety company (the bond issuer) guarantees to a project owner or claimant that a contractor will perform the contracted work and pay everyone downstream.
Bonding is a prerequisite to winning public work and increasingly required on large private projects. Your bonding capacity — the total dollar amount of contracts your surety will back — directly determines which jobs you can bid.
A bid bond guarantees that a contractor who wins a bid will enter into the contract at the quoted price. If the contractor walks away after winning, the surety compensates the owner for the cost difference of awarding to the next bidder. Required on most public projects at bid time.
A performance bond guarantees the contractor will complete the project according to contract terms. If the contractor defaults, the surety either completes the project itself, hires a replacement contractor, or compensates the owner up to the bond amount. Performance bonds are typically written at 100% of the contract value.
A payment bond guarantees that subcontractors, suppliers, and laborers will be paid. If the GC fails to pay, unpaid parties can make a direct claim against the bond. Payment bonds are the primary protection mechanism for subs and suppliers on public projects — they substitute for mechanic's liens, which cannot be placed on government-owned property.
A maintenance bond (also called a warranty bond) covers defects in workmanship or materials after project completion, typically for one to two years. Less common than performance and payment bonds; required on some public projects.
A surety is not an insurer — it expects to be repaid if it pays a claim. Before issuing bonds, a surety underwrites the contractor's ability to perform. The three primary factors, often called the three Cs, are:
Sureties set two limits: a single job limit (the maximum bond on any one contract) and an aggregate limit (the total bonded backlog across all open projects). Both limits are based on underwriting and can be increased as the contractor's financials strengthen.
Maintaining clean financials, audited or reviewed statements, and a claim-free bonding history are the primary levers for increasing bonding capacity over time.
Public work — federal, state, and local government projects — almost always requires performance and payment bonds by law. Thresholds vary by jurisdiction but are typically $25,000–$150,000. The contractor must have bonds in place before the contract is awarded.
Private work — bonds are not legally required but are increasingly requested by sophisticated owners, lenders, and developers. On private projects, mechanic's liens are the standard protection mechanism for unpaid subs and suppliers. Payment bonds on private projects replace liens voluntarily.
The Miller Act (40 U.S.C. §§ 3131–3134) is the federal law requiring performance and payment bonds on U.S. government construction contracts over $150,000. Both bonds must be written at 100% of the contract value.
Subcontractors and suppliers working on federal projects cannot lien government property. The payment bond fills that gap — it gives unpaid parties a direct claim against a bond instead.
Anyone who furnishes labor or materials on a Miller Act project has rights against the payment bond — but protection depends on tier and timing.
First-tier claimants (direct subs and suppliers to the GC) can claim directly against the bond without prior notice. Second-tier claimants (subs to subs, suppliers to subs) must give written notice to the GC within 90 days of last furnishing labor or materials.
All claimants must file suit within one year of the last day they furnished work or materials. Missing that deadline forfeits the claim entirely.
All 50 states have enacted their own versions — commonly called "Little Miller Acts" — applying the same bonding requirements to state and local public projects. Thresholds typically range from $25,000 to $100,000 and vary by state. Most mirror the federal structure, though notice periods and filing deadlines differ.
Private projects are not covered by the Miller Act or Little Miller Acts. On private work, the standard protection mechanism is a mechanic's lien.
For a GC bidding federal or public work, Miller Act compliance is not optional — bonds must be in place before the contract is awarded. That means your surety relationship and bonding capacity are prerequisites to winning the work, not afterthoughts.
For subcontractors, knowing your Miller Act rights is practical risk management. If you're on a federal project and payments stop, you have a direct claim against the payment bond — but only if you act within the statutory deadlines.
Bonding capacity is a ceiling on your ability to grow. A contractor with a $5M aggregate limit cannot take on $7M in concurrent bonded work — regardless of available crew or demand. Growing your bonding capacity requires:
Bonding capacity is one of the most direct ways your financial discipline translates into business opportunity. Contractors who manage their books tightly grow their limits faster than those who don't.