How to read a subcontractor’s certificate of insurance

A certificate of insurance is a snapshot, not a contract rewrite. It can show that a sub carries certain policies on a certain date—and it can still leave dangerous gaps if you treat it like a guarantee.

This is educational only—not legal advice on contract drafting, and not a recommendation to accept any particular risk transfer structure.

What a COI usually shows

A typical certificate summarizes:

• Insurer names and policy numbers
• Policy effective and expiration dates
• Coverage types (GL, auto, workers’ comp, umbrella, etc.)
• Limits (per occurrence, aggregate, and other listed amounts)
• Certificate holder name and address
• Sometimes notes about additional insured, waiver of subrogation, or primary/noncontributory wording

It is a summary, often prepared by an agent on standardized forms. Typos happen. Always compare the certificate to your written subcontract requirements.

For broader contractor coverage context, see general liability insurance for contractors and the contractor insurance starter guideline.

What a COI does not do

Critical educational points:

1. A COI is not the policy. Exclusions, endorsements, and retro dates live in the policy forms—not fully on the certificate.
2. A COI does not create coverage by itself. If someone needs to be an additional insured, that status generally comes from an endorsement (and must align with the contract).
3. A COI does not freeze coverage forever. Policies can be cancelled or changed; many certificates note that the insurer will “endeavor to” mail notice—but notice obligations vary and are easy to over-read.
4. Limits on a COI can be shared. An aggregate limit might already be eroded by other claims you cannot see from the certificate alone.

Matching certificates to contract requirements

Strong contract exhibits usually specify:

• Minimum GL limits and whether per-project aggregates are required
• Additional insured status for ongoing and completed operations (endorsement forms matter)
• Primary and noncontributory wording
• Waiver of subrogation where legally allowed
• Workers’ compensation—including employers’ liability limits
• Commercial auto if vehicles are used on site
• Umbrella/excess if higher total limits are required
• Professional liability for design-build or specialized consultants

When the COI arrives, check each line against that exhibit. “GL $1M” is incomplete if you also required completed-operations additional insured status and a per-project aggregate.

See also business insurance coverage types and workers compensation for small business.

Red flags when reviewing subcontractor COIs

Educational watch-outs:

• Expiration dates that end mid-project
• “Claims-made” professional liability with a recent retroactive date that does not cover the work period
• Missing workers’ comp in states/situations where employees will be on site
• Certificate holder listed, but no evidence of the additional insured endorsements your contract requires
• Self-insured retentions or unusual deductibles that your contract did not anticipate
• Residential exclusions on a sub’s GL when the job is a home remodel

When something looks off, ask for copies of the actual endorsements—not only a revised certificate with hopeful descriptions in the remarks box.

Additional insured vs certificate holder

These roles are routinely confused:

If your risk-transfer plan depends on additional insured protection, verify endorsements. Remarks on a COI are helpful clues, not a substitute for policy forms.

Ongoing monitoring during the project

Best-practice habits many GCs discuss with their advisors:

• Calendar renewal dates before they lapse
• Re-collect certificates after renewals and mid-term changes
• Confirm coverage when change orders expand scope into new trades
• Store COIs with the subcontract and job file
• Coordinate with your own GL and umbrella so project requirements stay consistent

Umbrella and excess layers sometimes sit above subcontractor GL; understanding total available limits may matter on larger jobs—see umbrella insurance explained.

Questions to ask your agent or counsel

1. Which endorsement forms satisfy our additional insured and completed-operations requirements?
2. Should we require primary/noncontributory and waiver language, and is it available in this market?
3. How do we verify workers’ comp for sole proprietors and owner-operators?
4. When should we request full policy copies instead of certificates alone?
5. How should COI requirements change for design professionals vs trade subcontractors?

Explore more in the small business learn hub, guidelines, tools, and state resources.

Related reading

• Professional liability vs general liability
• Directors and officers insurance basics
• Business income coverage explained

A certificate of insurance is a useful flashlight—not a force field. Treat it as one control in a broader program of contracts, endorsements, and verification, and you will catch gaps before a job-site claim tests them.