A subcontract is a separate, legally binding agreement in which a party already committed to a primary contract hires a third party to perform some portion of that work. The party doing the hiring is called the prime contractor; the party taking on the work is the subcontractor. The subcontractor has a direct legal relationship only with the prime contractor, not with the project owner, even though the work ultimately benefits the owner. This layered arrangement lets the prime contractor bring in specialized skills or extra labor while remaining fully responsible to the owner for the whole project.
The Privity Principle That Shapes Everything Else
The legal concept that governs how subcontracts work is privity of contract. Privity means only the parties who signed a contract can enforce it or be held liable under it. Because the subcontractor’s agreement is with the prime contractor, the subcontractor generally cannot sue the owner directly for unpaid invoices or disputes over scope. Those claims have to be directed at the prime contractor.
The same rule runs in the other direction. The project owner cannot directly control the subcontractor’s work methods or issue binding instructions to the subcontractor. The prime contractor acts as the intermediary: receiving directives from the owner, then passing them along through the terms of the subcontract. If a subcontractor’s work is defective or late, the owner looks to the prime contractor for a remedy, and the prime contractor then pursues the subcontractor.
Where Subcontracts Are Used
Subcontracting is standard in industries where a single project requires multiple specialized skills. In construction, a general contractor routinely hires subcontractors for electrical, plumbing, HVAC, concrete, and other trades. Each specialty firm signs its own subcontract, and the general contractor coordinates schedule and quality across all of them.
Federal government contracting relies heavily on the structure. Prime contractors managing large defense, infrastructure, or technology programs frequently subcontract portions to smaller firms with niche expertise. Businesses working on federal projects typically need a Unique Entity Identifier and registration in the System for Award Management at SAM.gov, even at the subcontractor level.1U.S. Small Business Administration. Basic Requirements
Information technology firms use subcontracts to bring in developers for niche programming languages, cybersecurity audits, or cloud migrations. The same model appears in oil and gas, aerospace, and professional services wherever a project demands a combination of technical disciplines.
What a Subcontract Has to Spell Out
A well-drafted subcontract defines exactly what each party owes the other. A handful of elements appear in nearly every enforceable version.
Scope of Work and Timeline
The scope defines the exact tasks the subcontractor will perform, including materials, applicable specifications, and the physical boundaries of the work. Vague descriptions invite disputes, so good subcontracts reference drawings, specifications, and even specific sections of the prime contract.
The timeline covers a start date, key milestones, and a firm completion deadline. Many subcontracts tie missed deadlines to liquidated damages, a predetermined dollar amount owed per day of delay. Without that, proving the actual cost of a delay in court is far harder.
Payment Terms and Retainage
The subcontract should state the compensation structure: lump sum, unit pricing, cost-plus a markup, or hourly rates. It should also specify when invoices are due, how quickly payment follows, and what documentation (lien waivers, certified payroll) each invoice must include.
In construction, the prime contractor typically withholds 5 to 10 percent of each progress payment as retainage, a reserve held until the subcontractor’s work is fully completed and accepted. Some jurisdictions cap retainage by statute, and many require release within a set number of days after the subcontractor’s portion is finished. If your subcontract is silent on retainage, the prime contractor may apply whatever percentage they choose.
Insurance
Most subcontracts require commercial general liability coverage, often with a minimum of $1,000,000 per occurrence. Workers’ compensation, automobile liability, and professional liability (for design or engineering work) may also be required. The subcontract usually requires the subcontractor to name the prime contractor and owner as additional insureds and to produce certificates of insurance before work begins.
Flow-Down Clauses
A flow-down clause takes obligations from the prime contract and passes them into the subcontract, binding the subcontractor to the same standards the prime contractor owes the owner. These clauses cover safety protocols, quality standards, dispute resolution methods, and reporting deadlines. Once a subcontract is signed, the subcontractor is responsible for meeting those flowed-down requirements, even if they never saw the prime contract itself.
Flow-down is especially detailed in federal contracting. The Federal Acquisition Regulation requires prime contractors to include specific FAR clauses in their subcontracts, covering ethics and whistleblower protections, equal opportunity, small business utilization, cybersecurity safeguards, and prohibitions on certain telecommunications equipment.2Acquisition.GOV. FAR 52.244-6 Subcontracts for Commercial Products and Commercial Services A separate FAR provision lists the minimum clauses that must flow down even in subcontracts for commercial products and services.3Acquisition.GOV. FAR 52.212-5 Contract Terms and Conditions Required To Implement Statutes or Executive Orders – Commercial Products and Commercial Services
In private-sector work, flow-down clauses are negotiable but still matter. If the prime contract requires compliance with specific environmental regulations, building codes, or safety rules, the subcontractor has to follow them too. Ask to review the relevant sections of the prime contract before signing. Flow-down obligations can create liability a subcontractor never anticipated.
Getting Paid When Something Goes Wrong
Because the subcontractor has no direct contractual relationship with the owner, recovering unpaid money takes a different set of tools than a standard breach of contract claim.
Mechanic’s Liens
Every state has a mechanic’s lien statute that lets subcontractors who furnished labor or materials place a lien on the improved property, even without a contract with the owner. The lien gives the subcontractor a security interest in the property itself, which can force a sale if the debt stays unpaid. Filing deadlines vary widely by state, from roughly 60 days to one year after the subcontractor’s last day of work. Many states also require a preliminary notice to the owner within a set period to preserve the right to file. Missing the notice or filing deadline can permanently forfeit the lien, so the state’s specific requirements have to be checked.
Miller Act Bonds on Federal Projects
Mechanic’s liens are not available on federal property. On federal construction projects worth more than $100,000, the Miller Act instead requires the prime contractor to furnish a payment bond covering all subcontractors and suppliers.4Office of the Law Revision Counsel. 40 USC Subtitle II, Part A, Chapter 31, Subchapter III A first-tier subcontractor (contracted directly with the prime) can sue on the payment bond in federal court no earlier than 90 days and no later than one year after their last day of work, with no prior notice requirement. Second-tier subcontractors, those hired by a first-tier subcontractor rather than the prime, must send written notice to the prime contractor within 90 days of their last day of work before filing suit.5General Services Administration. The Miller Act
Pay-When-Paid and Pay-If-Paid Clauses
Many subcontracts tie the subcontractor’s payment to whether or when the prime contractor receives payment from the owner, and the legal effect depends on the exact wording. A “pay-when-paid” clause is generally treated as a timing mechanism: the prime contractor has to pay within a reasonable time even if the owner is slow. A “pay-if-paid” clause, by contrast, attempts to make the owner’s payment an actual condition that must occur before the prime contractor owes anything, shifting the entire risk of owner default onto the subcontractor.
Several states, including California, New York, North Carolina, and Illinois, refuse to enforce pay-if-paid clauses on public policy grounds or have banned them outright in private construction. If a subcontract contains one of these clauses, check whether your state enforces it before concluding you have no recourse.
Prompt Payment Statutes
Many states have prompt payment laws requiring prime contractors to pay subcontractors within a set number of days after receiving payment from the owner, with interest penalties for late payment. Interest rates under these laws commonly range from 1 to 2 percent per month. On the federal side, the FAR requires the government to pay prime contractors within 30 days of receiving a proper invoice, with interest penalties computed under the Office of Management and Budget’s prompt payment rules.6Acquisition.GOV. FAR 52.232-25 Prompt Payment
Change Orders, Indemnification, and Termination
Change Orders
Almost every project involves changes after signing: design revisions, unforeseen site conditions, or new owner requests. A change order is a written modification that adjusts the scope, price, or schedule. Most subcontracts require changes to be documented in writing before the extra work begins. A subcontractor who performs additional work without a signed change order risks losing the right to compensation for that work entirely.
Even before a formal change order is issued, send written notice to the prime contractor whenever an event occurs that could change the scope. That notice is separate from the change order itself and preserves the right to seek additional payment. Verbal approval, without written documentation, rarely holds up when it is time to collect.
Indemnification
Nearly every subcontract includes an indemnification clause requiring the subcontractor to defend and hold harmless the prime contractor, and often the owner, against claims arising from the subcontractor’s work. If a third party is injured or property is damaged because of what the subcontractor did, the subcontractor pays the defense costs and any judgment.
Scope varies. A narrow-form clause covers only losses caused by the subcontractor’s own negligence. A broad-form clause can require the subcontractor to pay for losses even when the prime contractor or owner was partially at fault. Approximately 45 states have enacted anti-indemnity statutes that limit or void broad-form clauses in construction contracts. Review the indemnification language before signing and check whether your state restricts what can be enforced.
Many subcontracts also include limitation-of-liability provisions that cap total damages and may exclude consequential damages such as lost profits. These caps interact with the indemnification clause, so both have to be read together.
Termination for Cause and for Convenience
Subcontracts typically give the prime contractor two ways to end the relationship early.
Termination for cause ends the subcontract because the subcontractor failed to perform: missed deadlines, defective work, or abandonment. The prime contractor can hire a replacement and charge the original subcontractor for any additional cost. If the termination is later found to be wrongful, because the prime contractor failed to give required notice or acted in bad faith, the prime contractor may owe damages including lost anticipated profits.
Termination for convenience ends the subcontract even though the subcontractor has not defaulted. The subcontractor is typically entitled to payment for work completed to date, plus reasonable demobilization costs and overhead, but not lost future profits. The prime contractor must still exercise this right in good faith and cannot manufacture a justification to get rid of a subcontractor.
Some subcontracts include a conversion clause providing that a wrongful termination for cause will automatically be treated as a termination for convenience, limiting the prime contractor’s exposure. Even then, a prime contractor who acts in bad faith may lose the protection of the conversion clause.
Employee or Independent Subcontractor
One of the most consequential legal issues around subcontracts is whether the worker is genuinely an independent subcontractor or should be classified as an employee. The IRS uses a three-factor test:7Internal Revenue Service. Independent Contractor (Self-Employed) or Employee?
- Behavioral control: does the hiring party control how and when the worker performs the job, or only the end result?
- Financial control: does the hiring party control how the worker is paid, whether expenses are reimbursed, and who provides tools and supplies?
- Type of relationship: is there a written contract, are benefits provided, and is the work a key part of the hiring party’s regular business?
No single factor is decisive. The IRS weighs the overall degree of control and independence. The more control the hiring party exercises over the details of the work, the more likely the worker is an employee, regardless of what the contract says.
For tax years beginning after 2025, a business that pays a subcontractor $2,000 or more during the year must file Form 1099-NEC with the IRS reporting those payments.8Internal Revenue Service. 2026 Publication 1099 The threshold was previously $600. The subcontractor is responsible for paying their own income taxes and self-employment taxes on amounts received.
Getting classification wrong is expensive. Misclassifying an employee as an independent contractor can deny the worker minimum wage, overtime pay, and other protections under the Fair Labor Standards Act.9U.S. Department of Labor. Final Rule: Employee or Independent Contractor Classification Under the Fair Labor Standards Act The IRS imposes its own penalties under Section 3509 of the tax code, including unpaid withholding and a share of Social Security and Medicare taxes that should have been collected, with those amounts doubling if required information returns were not filed.10Office of the Law Revision Counsel. 26 U.S. Code 3509 – Determination of Employer’s Liability for Certain Employment Taxes State-level penalties can apply on top of the federal ones.