COI terms for general contractors, explained.
Certificates of insurance are full of acronyms and endorsement form numbers. These plain-English definitions explain exactly what each term means, why it matters when you hire subcontractors, and what to look for on the certificate.
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Start with the basics—what a certificate of insurance is—then dig into the endorsements that decide whether a sub’s coverage actually protects you.
Certificate of insurance (COI)
The one-page proof-of-coverage document—almost always the ACORD 25—that summarizes a policyholder’s active insurance.
Read the definitionACORD 25
The standardized Certificate of Liability Insurance form that is the industry-standard COI.
Read the definitionAdditional insured (CG 20 10 vs CG 20 38)
An endorsement that extends a sub’s liability coverage to the GC—via forms like CG 20 10, CG 20 37, and CG 20 38.
Read the definitionWaiver of subrogation
A provision where an insurer gives up its right to recover from a named party after paying a claim.
Read the definitionPrimary and non-contributory
Contract language making the sub’s policy pay first without seeking contribution from the GC’s policy.
Read the definitionCertificate holder
The party a COI is issued to as proof of coverage—often confused with, but different from, an additional insured.
Read the definitionCommercial general liability (CGL)
The core third-party liability policy GCs require of subs, covering bodily injury and property damage from their work.
Read the definitionWorkers’ compensation
Coverage for a subcontractor’s employees’ job-site injuries—usually legally required and paired with employer’s liability.
Read the definitionUmbrella / excess liability
A policy that stacks additional limits on top of a sub’s general liability and auto coverage to reach a GC’s required totals.
Read the definitionCompleted operations
The coverage that responds to claims arising after a sub finishes work—critical for construction defect exposure.
Read the definitionNamed insured
The business that owns the policy—distinct from an additional insured, and the name that must match your subcontract.
Read the definitionAggregate limit
The most a policy will pay in total during the policy term—why a per-project aggregate endorsement often matters.
Read the definitionEndorsement
An amendment that adds, removes, or changes coverage on a policy—the actual proof behind a COI’s checkboxes.
Read the definitionLet software read the certificates for you.
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