Most GC compliance teams know to collect a COI from every subcontractor before work starts. Fewer know what to do with it once it arrives. Checking that the paper has the right date and a large-enough number in the GL field is not a compliance review - it's an administrative filing step that misses most of the risk.
A complete subcontractor COI review requires checking every field against the governing subcontract, verifying endorsements that aren't visible on the certificate face, and confirming that the coverage forms match what the project actually needs.
What the ACORD 25 Certificate Shows for Construction
Key COI Sections to Verify
The ACORD 25 is the standard certificate form used in construction. Understanding what each section does - and does not - tell you is essential for effective review.
Commercial General Liability Section
| ACORD 25 Field | What to Check | What It Doesn't Show |
|---|---|---|
| Each occurrence limit | Meets subcontract minimum | Whether completed ops AI is endorsed |
| General aggregate | Meets subcontract minimum (2x per-occ typical) | Whether aggregate is per-project or blanket |
| Products/completed ops aggregate | Meets subcontract minimum | Duration of completed ops coverage |
| Personal/advertising injury | Present and at minimum | N/A |
| GL policy type checkbox | Occurrence (preferred) | Form number or endorsements |
Critical hidden issue - Per-Project vs. Blanket Aggregate: Many GL policies have a blanket aggregate that covers all operations. Some policies offer a per-project aggregate endorsement, which provides a fresh aggregate for each project. A sub with a $2M blanket aggregate who is active on five projects has, in theory, only $400K per project in aggregate capacity if multiple claims arise simultaneously. Subcontracts that require a per-project aggregate (CG 25 03 or similar) must verify this endorsement is present.
Automobile Liability Section
| Field | What to Check |
|---|---|
| Combined single limit | Meets subcontract minimum (typically $1M) |
| Covered autos | All autos (symbol 1) or combination covers owned, hired, non-owned |
| Hired/non-owned auto | Required if sub uses rented vehicles or employees' personal vehicles |
Workers' Compensation and Employers' Liability
| Field | What to Check |
|---|---|
| WC statutory limits | "Statutory" is correct; confirm state(s) of coverage |
| Employers' liability per accident | Meets subcontract minimum (typically $500K-$1M) |
| Employers' liability policy limit | Meets subcontract minimum |
| Employers' liability per employee | Meets subcontract minimum |
| WOS checkbox | Indicates waiver of subrogation - must confirm on policy |
Umbrella / Excess Liability
| Field | What to Check |
|---|---|
| Each occurrence | Meets subcontract minimum |
| Aggregate | Meets subcontract minimum |
| Follow form | Should note "follows form" over GL, auto, employers' liability |
| Retention/deductible | Note any SIR that affects effective coverage |
What the ACORD 25 Does Not Tell You (And Must Be Verified Separately)
Additional Insured Endorsement Status
The ACORD 25 has a checkbox indicating "Additional Insured" and a description-of-operations field. These do not confirm:
Which AI endorsement form is being used. CG 20 10 (ongoing operations) and CG 20 37 (completed operations) are different endorsements. Many subs provide CG 20 10 only. If the subcontract requires completed operations coverage, CG 20 37 must also be endorsed.
Whether the endorsement is on the policy. The checkbox and description field can be completed on the certificate even if the actual endorsement was not added to the policy. Verification requires calling the insurer or requesting the endorsement form itself.
Whether primary/noncontributory language is included. The standard AI endorsement does not automatically provide primary/noncontributory coverage. A separate endorsement (CG 20 01 or equivalent) or specific policy language is required. Without it, the GC's and sub's insurers may share the claim proportionally rather than the sub's policy responding first.
Waiver of Subrogation Status
The WOS checkbox on the ACORD 25 indicates that the sub's insurer has agreed not to pursue the GC. But:
WOS must be on the policy, not just the certificate. A COI can list WOS in the description field; the insurer may claim no such endorsement exists when a claim occurs.
WOS must cover all three primary lines - GL, WC, and auto. Many subs provide WOS on GL but not on workers' compensation. If the sub's WC insurer can subrogate against the GC for a site condition that contributed to the worker's injury, the WOS value is significantly reduced.
WOS endorsements vary. Some are blanket (apply when required by contract), some are scheduled (list specific parties). Blanket endorsements require that the sub's agreement with the GC qualifies as a written contract under the endorsement's terms.
Policy Exclusions
No exclusions appear on the ACORD 25 face. For construction, relevant exclusions to investigate:
Work exclusions (your work / your product): GL policies exclude damage to the insured's own work. On a subcontract, this means the sub's GL typically won't cover damage to the work the sub performed - only damage to other property. This is standard and expected, but GCs should understand it.
Subsidence exclusion: Relevant for excavation and grading subs. Damage from ground movement may be excluded from standard GL.
Earth movement exclusion: Similar to subsidence; relevant for subs working near existing structures.
Professional liability exclusion: Standard GL policies exclude claims arising from professional services (design, engineering advice). Subs with design responsibilities need professional liability coverage.
Step-by-Step: How to Review a Subcontractor COI
COI Review Process
Step 1: Open the subcontract and locate the insurance exhibit. Write down every required coverage type, minimum limit, and endorsement requirement.
Step 2: Compare the COI face to the list. For each coverage type: Is it present? Does the limit meet or exceed the minimum?
Step 3: Check the named insured against the subcontract. The entity that signed the subcontract must be the named insured on every policy.
Step 4: Confirm the certificate holder is your entity - correct legal name, address.
Step 5: Check the description-of-operations for endorsement references. Note any that are claimed (AI, WOS, primary/noncontributory) for follow-up verification.
Step 6: Call the agent and confirm: AI endorsement form and number (CG 20 10, CG 20 37, or equivalent); WOS endorsement on GL, WC, and auto; primary/noncontributory endorsement if required.
Step 7: For high-value or high-risk subcontracts, request copies of the AI and WOS endorsements.
Step 8: Document your review with the date, what was checked, what was confirmed, and any gaps.
Frequently Asked Questions
What is the difference between CG 20 10 and CG 20 37? CG 20 10 is the Additional Insured endorsement for ongoing operations - it provides AI coverage while the sub is actively working on the project. CG 20 37 is the Additional Insured endorsement for completed operations - it continues AI coverage after the sub's work is complete. For construction, both are typically required, with CG 20 37 remaining in force for the duration of the applicable statute of repose.
Can I rely on the description-of-operations field to confirm endorsements? No. The description-of-operations field is informational - it can say anything. The actual endorsement must be on the policy for coverage to exist. Always confirm endorsements directly with the insurer or agent.
What does "per project aggregate" mean and should I require it? A per-project aggregate provides a fresh GL aggregate for each construction project the sub works on. Without it, a sub active on multiple projects has a shared aggregate that can be depleted by claims on other projects, leaving inadequate coverage for yours. For large-value subcontracts or high-risk trades, a per-project aggregate is worth requiring.
How do I verify workers' compensation is actually in force? The most reliable method is to verify directly with the WC insurer or through the state workers' compensation board. Some states maintain online lookup tools for active WC policies. Fraudulent WC COIs are a documented problem in construction - particularly from smaller subcontractors.
A subcontractor certificate of insurance is a document, not a compliance confirmation. The compliance work happens when you compare every field against the subcontract requirements and verify the endorsements that don't appear on the certificate face.
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