When you receive a certificate of insurance from a vendor, the ACORD form itself is just a summary. The real protection lives in the endorsements attached to the underlying policy. Three endorsements appear more than any others in commercial contracts: additional insured, primary and noncontributory, and waiver of subrogation.
Each one serves a distinct purpose in transferring risk away from your organization and onto your vendor’s insurance policy. Understanding what they do (and what they don’t do) is essential for anyone managing vendor compliance.
Additional Insured
An additional insured endorsement extends the vendor’s liability coverage to include your organization. Without it, you are simply a certificate holder, which means you have proof that the vendor carries insurance but no right to make a claim under their policy.
With additional insured status, your organization gains the right to defense and indemnification under the vendor’s policy for claims arising out of that vendor’s work. If a vendor’s employee causes property damage or bodily injury at your facility, your organization can look to the vendor’s insurer for protection rather than filing against your own policy.
There are two common forms of this endorsement. A scheduled endorsement names your organization specifically. A blanket endorsement automatically extends coverage to any party the vendor is contractually required to include. Blanket endorsements are administratively simpler, but they can create ambiguity if the contractual language is not precise.
One critical limitation: additional insured coverage is typically narrower than what the named insured (your vendor) receives. Coverage may be limited to liability arising from the named insured’s ongoing operations, and it may or may not extend to completed operations after work is finished. Reviewing the actual endorsement form, not just the COI checkbox, is the only way to confirm the scope of coverage.
Primary and Noncontributory
Being named as an additional insured is only part of the equation. Without primary and noncontributory language, your vendor’s insurance and your own insurance may end up sharing the cost of a claim, or worse, your insurer may be asked to respond first.
The “primary” designation means the vendor’s policy responds before your own. The “noncontributory” designation means the vendor’s insurer will not seek contribution from your policy. Together, these terms ensure that when a claim arises from your vendor’s work, their insurance handles the full cost up to policy limits without involving your coverage at all.
This matters for two practical reasons. First, it keeps your loss history clean. Claims paid under your own policy affect your experience modification rate and can increase your future premiums. Second, it eliminates disputes between carriers. When two insurers both believe the other should pay, the resulting delays can leave your organization exposed during litigation.
Without this endorsement, most commercial general liability policies default to a proportional sharing arrangement. The vendor’s insurer and your insurer each contribute based on their respective policy limits, which means your organization absorbs part of the financial impact for a loss your vendor caused.
The primary and noncontributory endorsement is most commonly required in construction, property management, and any engagement where a vendor’s activities create significant liability exposure on your premises or projects.
Waiver of Subrogation
Subrogation is the legal right of an insurance company to recover its claim payments from the party responsible for the loss. After paying a claim, the insurer essentially steps into the shoes of the insured and pursues the at fault party for reimbursement.
A waiver of subrogation endorsement removes that right. When your vendor’s policy includes this waiver in your favor, the vendor’s insurer agrees not to come after your organization to recoup payments, even if your organization was partially at fault for the loss.
Consider a scenario where a vendor is working at your facility and one of their employees is injured due to a condition on your property. The vendor’s workers’ compensation insurer pays the claim. Without a waiver of subrogation, that insurer can then sue your organization to recover those payments. With the waiver in place, the insurer absorbs the cost and the matter is closed.
Like additional insured endorsements, waivers of subrogation come in scheduled and blanket forms. A scheduled waiver names your organization specifically. A blanket waiver applies automatically to any party the vendor has contractually agreed to protect. Blanket waivers are more common because they reduce administrative friction for vendors working with multiple clients.
There is a cost consideration on the vendor side. Adding a waiver of subrogation typically increases the vendor’s premiums because the insurer takes on additional risk by giving up recovery rights. For workers’ compensation specifically, waived subrogation can also affect the vendor’s experience modification rate since unrecoverable claims remain on their record.
How These Endorsements Work Together
In practice, these three endorsements function as complementary layers of protection. Additional insured status gives you coverage rights under the vendor’s policy. Primary and noncontributory language ensures that coverage responds first and exclusively. Waiver of subrogation prevents the vendor’s insurer from circling back to recover costs from your organization after a claim is paid.
Contracts in construction, real estate, and facility management commonly require all three. The standard language you will often see in a contract reads something like: “The vendor’s coverage for the additional insured must be primary, noncontributory, and include a waiver of subrogation.”
What a COI Actually Proves
It is worth noting that a certificate of insurance is an informational document, not a contract. The COI summarizes coverage details, but it does not amend the underlying policy. Checking the “additional insured” box or noting “primary and noncontributory” in the description of operations section does not guarantee that the actual policy endorsements are in place.
This is precisely why compliance teams need to verify not just the COI itself, but the endorsements backing it up. A COI that says all the right things is worthless if the underlying policy lacks the corresponding endorsements. Relying on manual review of these details across dozens or hundreds of vendors is where most organizations fall behind, and where coverage gaps go unnoticed until a claim hits.
Proactive tracking and automated verification of endorsement requirements is the most reliable way to ensure your vendor insurance program delivers the protection your contracts require.