What Does a COI Cover? A Field Guide for GC Office Managers

A certificate of insurance (COI) covers nothing. The underlying policies cover things. The COI is a one-page snapshot that tells you which policies exist, what types of coverage they carry, what the limits are, and whether specific endorsements have been added. Understanding that distinction is not semantic pedantry — it is the difference between a contractor who is actually insured for your job and one who handed you a piece of paper that looks like they are.

By Nick Streicher, Founder, StrikeDocs. Published 2026-04-15.

This guide explains every section of a standard ACORD 25 COI, what each coverage type means in practice, which endorsements matter for construction contracts, and where COIs routinely fail to say what GCs need them to say. If you already know the basics of reading an ACORD 25, this builds on that foundation — see How to Read an ACORD 25 Certificate of Insurance for a field-by-field walkthrough of the form itself.

What a COI actually is (and what it isn't)

ACORD 25 is the industry-standard form. The certificate holder — typically you, the GC, property owner, or project owner — receives it as evidence that the named insured (your subcontractor or vendor) has purchased the listed policies from the listed insurers.

Two disclaimers are printed directly on every ACORD 25:

"This certificate is issued as a matter of information only and confers no rights upon the certificate holder."
"This certificate does not affirmatively or negatively amend, extend or alter the coverage afforded by the policies below."

In plain language: a COI cannot give you rights that the actual policy doesn't give you. If the policy has an exclusion for subsidence and the COI doesn't mention it, you don't have subsidence coverage. If the policy requires the named insured to notify the insurer before additional insured status is triggered and that step wasn't taken, you may not be an additional insured even if the COI says you are.

A COI tells you what to go verify. It is not itself verification.

The six coverage types you'll see on a COI

ACORD 25 has dedicated rows for six major coverage categories. Here is what each one actually covers in a construction context.

Commercial General Liability (CGL)

CGL is the foundational coverage on almost every subcontractor COI. It covers third-party bodily injury and property damage arising from the named insured's operations. For a sub working on your site, that means:

A laborer drops a tool and injures a visitor — CGL.
The sub's crew damages an adjacent tenant's property — CGL.
A completed project causes injury after the sub has left — CGL's "products and completed operations" coverage.

The standard ACORD 25 form captures four CGL sub-limits:

Each Occurrence — the max the insurer pays for a single incident.
General Aggregate — the max paid across all claims during the policy period (often 2× each occurrence).
Products/Completed Operations Aggregate — a separate aggregate for claims arising after the work is done.
Personal & Advertising Injury — covers libel, slander, copyright infringement.

You need to check all four. A policy with a $1M each-occurrence limit and a $1M general aggregate that's already been partially eroded by other claims may leave you exposed on a project-specific claim.

Workers' Compensation and Employers' Liability

WC covers the named insured's employees for on-the-job injuries, regardless of fault. This is the coverage that matters most for protecting you from employee-injury claims being redirected at you under employer liability theories.

The COI will show:

WC Statutory — means the policy pays whatever the state statute requires, with no dollar cap. You want "Statutory" here, not a specific dollar amount.
Employers' Liability (EL) — three sub-limits: each accident, disease policy limit, disease each employee. These cover the named insured against suits that fall outside the WC exclusivity bar.

If a subcontractor shows up without WC coverage and a worker is injured on your site, you may end up liable. Many states allow injured workers to pursue the general contractor as a "statutory employer" when the direct employer lacks coverage.

Commercial Auto

Covers bodily injury and property damage arising from the use of covered vehicles — owned, hired, and non-owned. "Non-owned auto" is the one GCs forget to check. If a subcontractor's employee drives their personal vehicle to the job site and causes an accident, non-owned auto coverage is what responds first.

The COI will show a combined single limit (CSL) for auto — typically $1M for commercial work.

Umbrella / Excess Liability

Sits above the primary CGL, auto, and EL limits. If a claim exceeds the underlying policy's per-occurrence limit, the umbrella responds up to its own limit. On projects with significant exposure — high-rise work, large public-access spaces, anything with explosion or collapse risk — confirming the umbrella follows form (covers what the underlying policies cover, not a narrower scope) matters.

Professional Liability (Errors & Omissions)

Covers economic loss arising from professional errors — design errors, specification mistakes, coordination failures. This is standard for architects, engineers, and design-build subs. It is a claims-made policy, which means the claim must be made during the policy period. When the sub's policy expires, the coverage for past work expires too unless a tail (extended reporting period) is purchased.

CGL does not cover professional liability. If you have a design-build sub and you're only looking at their CGL limit, you're looking at the wrong policy for design errors.

Garage Liability

Specialized coverage for auto dealers, repair shops, and parking operators. You'll rarely see it on a standard subcontractor COI unless the sub operates vehicle storage or a fleet maintenance facility.

Endorsements that change what a COI actually means for you

The coverage-type rows tell you a policy exists. The endorsements tell you whether it works the way your contract requires.

Additional Insured (AI)

The single most important endorsement for GCs. Being listed as an additional insured on the sub's CGL policy means the insurer defends and indemnifies you for claims arising from the sub's operations — not just the sub.

The endorsement form number matters. The most common in commercial construction are:

CG 20 10 — covers ongoing operations.
CG 20 37 — covers completed operations.
CG 20 26 — designates a specific person or organization.

Your contract should require both CG 20 10 and CG 20 37. Many COIs list only CG 20 10, which means you lose additional insured protection the moment the sub's work is done — exactly when completed-operations claims start appearing.

The ACORD 25 description box is where this gets noted, but there's no standardized field. Some brokers type the endorsement number. Others type "Additional Insured per contract." The latter is not meaningful confirmation of which endorsement form was attached.

Waiver of Subrogation

Without this, the sub's insurer can pay a claim and then sue you to recover what it paid, arguing your negligence contributed to the loss. A waiver of subrogation endorsement prohibits that recovery action. Most standard construction contracts require it.

Primary and Noncontributory

If your own GL policy and the sub's GL policy both cover the same claim, the default rule is that they share the loss proportionally. A primary and noncontributory endorsement requires the sub's policy to pay first and in full before your policy contributes anything. This protects your own aggregate limits and prevents your premiums from being affected by claims that are really the sub's fault.

Limits: what those numbers actually tell you

Limits on a COI are the maximum the insurer will pay. They are not a guarantee of that amount. Policy aggregates erode across the policy period. A sub who had three smaller claims earlier in the year may have a $1M general aggregate that's effectively $400K by the time they start your job.

A COI does not show you aggregate erosion. The only way to get that information is to request it directly from the insurer or broker.

Project-specific policies (also called project-specific wrap-ups or OCIPs) address this by issuing a policy tied to the project rather than the named insured's annual renewal cycle. If you're managing large projects and accepting individual subcontractor COIs, you're accepting erosion risk you can't see from the certificate.

What a COI does NOT cover

Being precise about the gaps matters more than cataloging what's present.

Pollution liability — excluded from standard CGL. If your sub does any work involving hazardous materials, fuel systems, or excavation near contaminated soil, you need a separate pollution liability policy. This is not on the ACORD 25's standard coverage rows.

Cyber liability — excluded from standard CGL as of ISO's 2016 exclusions. Relevant for subs with access to your systems or BIM data.

Employment practices liability — claims of discrimination, harassment, wrongful termination. CGL doesn't cover these. Separate EPLI policy required.

Builder's risk — property coverage for the structure under construction. This is a project-owner or GC-obtained policy in most contracts. The sub's CGL does not cover the project itself.

Intentional acts — no commercial policy covers deliberate wrongdoing.

Contractual liability beyond the insured contract definition — CGL covers "insured contracts," which include construction contracts, but it has limits. Indemnification agreements that go beyond what ISO defines as an insured contract may not be covered.

What we learned running 59 real COIs through StrikeDocs

We processed 59 certificates through StrikeDocs across a range of states and project types. Here's what the data showed:

GL was the most common coverage type at 27.0% of all policies across the corpus, followed by Workers' Compensation at 21.3% and Auto at 20.1%. Umbrella appeared in only 14.4% of policies — meaning a significant share of the documents had no excess layer at all.
Additional Insured endorsements appeared on only 33.9% of policies. Waiver of Subrogation was present on 21.3%. Primary and Noncontributory language appeared on just 15.5%. These three endorsements are required by nearly every standard subcontract — yet the majority of policies in this real-world corpus were missing at least one of them.
The median GL each-occurrence limit was $10,000, with a range of $2,500 to $40,000, and 100% of policies fell below $1M. Every single GL policy in this dataset was below the $1M each-occurrence limit that most commercial contracts require as a floor. This suggests a substantial share of COIs collected in the field are technically non-compliant with standard contract minimums before you even look at endorsements.
69.5% of documents contained two or more policies, averaging 2.9 policies per document. A COI is rarely a single-policy document in practice — and each policy line has to be checked independently against contract requirements.

Here is an example of StrikeDocs parsing the endorsement description block from a real COI in the corpus:

$ strikedocs parse --file sub_coi_2026_04.pdf --check-endorsements

[INFO] Parsing document: sub_coi_2026_04.pdf
[INFO] Identified policies: GL, WC, AUTO, UMBRELLA

[GL] Each Occurrence: $1,000,000
[GL] General Aggregate: $2,000,000
[GL] Products/CompOps Aggregate: $2,000,000

[ENDORSEMENTS DETECTED]
  ✓ Additional Insured: CG 20 10 04 13 (ongoing ops)
  ✗ Additional Insured: CG 20 37 — NOT FOUND (completed ops missing)
  ✗ Waiver of Subrogation — NOT FOUND
  ✓ Primary & Noncontributory — detected in description block

[COMPLIANCE CHECK]
  Contract requirement: AI (ongoing + completed ops) + WOS + P&NC
  Result: NON-COMPLIANT — missing CG 20 37, missing Waiver of Subrogation

[ACTION] Flag for certificate holder review before work authorization.

StrikeDocs compliance report showing missing CG 20 37 and Waiver of Subrogation flags

The CG 20 10 04 13 form was the most frequently occurring endorsement in our corpus with 7 total instances across two punctuation variants — yet the companion CG 20 37 for completed operations appeared far less consistently. That's the pattern that matters: GCs getting partial additional insured protection and not knowing it.

How to verify what a COI claims to cover

A COI is a starting point, not a finish line. Here is a practical verification workflow.

Step 1: Confirm the policy is active. Call the broker or insurer listed on the certificate. Verify the policy number matches what's on the COI and that it has not been canceled or non-renewed.

Step 2: Request the actual endorsement pages. If the COI lists CG 20 10, ask for the endorsement itself from the policy. It will name you as an additional insured. "Per contract" language on a COI without the endorsement behind it is unenforceable.

Step 3: Check aggregate erosion. Ask the broker for a loss run or a statement of aggregate availability. This is especially important for subs who work multiple jobs simultaneously.

Step 4: Verify the policy period covers your project timeline. A COI valid through June 30 on a project running through September is a problem. For completed operations, you want the policy — or tail coverage — to extend beyond substantial completion.

Step 5: Cross-reference against your contract requirements. Your subcontract should specify minimum limits, required coverage types, and required endorsements. Check the COI against that list explicitly, field by field.

Automating steps 1 and 5 is what StrikeDocs is built for. The parsing output above shows what a structured compliance check against a predefined contract requirement set looks like in practice.