What Is a Certificate of Insurance (COI)? A Property Manager's Guide

If you manage residential or commercial properties, you already know that vendors come and go constantly. Landscapers, plumbers, roofers, elevator technicians, janitorial crews -- the list grows with every unit you add to your portfolio. But before any of these vendors set foot on your property, there is one document you should always have on file: a Certificate of Insurance, commonly known as a COI.

COI Defined

A Certificate of Insurance is a standardized document -- typically an ACORD 25 or ACORD 28 form -- issued by a vendor's insurance carrier or broker. It summarizes the vendor's active insurance policies, including policy numbers, effective dates, coverage types, and liability limits. The COI does not confer coverage on the certificate holder; it simply provides evidence that coverage exists as of the date the certificate was issued.

Think of a COI the way you think of a driver's license. It does not make someone a safe driver, but it confirms that, at minimum, they have met the requirements to operate on the road.

Why COIs Matter for Property Managers

When a vendor causes property damage, injures a resident, or harms one of their own workers on your premises, you need to know that the vendor carries adequate insurance to cover the claim. Without a valid COI on file, your property -- and by extension, your ownership group or management company -- may bear the financial exposure.

For managers overseeing 200 to 2,000 units, the stakes multiply quickly. A single uninsured incident involving a subcontracted roofer or an unlicensed electrician can produce six- or seven-figure liability. Courts and insurance adjusters will look at whether you exercised reasonable diligence in vetting your vendors. A current, compliant COI is one of the strongest pieces of evidence you can produce.

What to Look for on a COI

Not all COIs are created equal. When reviewing a certificate, pay attention to the following:

• Named insured. Confirm the legal entity on the COI matches the vendor you contracted with. A COI issued to "Smith Plumbing LLC" does not cover work performed by "Smith & Sons Plumbing Inc."
• Policy effective and expiration dates. Coverage must be active during the period the vendor is performing work. Expired certificates offer zero protection.
• Coverage types. At a minimum, most property managers require Commercial General Liability (CGL) and Workers' Compensation. Depending on the scope of work, you may also require Commercial Auto, Professional Liability, or Umbrella/Excess Liability.
• Limits of liability. Your management agreement or ownership group likely sets minimum per-occurrence and aggregate limits. Common thresholds are $1 million per occurrence and $2 million aggregate for general liability, but requirements vary by property type and jurisdiction.
• Additional insured status. Your entity should be listed as an additional insured on the vendor's general liability policy. This gives you direct rights under the vendor's policy if a claim arises from their work.
• Certificate holder information. Your company name and address should appear in the certificate holder box, confirming the certificate was issued specifically for your benefit.

Common Mistakes

The most frequent compliance gap we see among property managers is treating COI collection as a one-time event. Insurance policies renew, lapse, and change throughout the year. A COI that was valid in January may be worthless by March if the vendor failed to renew. Ongoing monitoring -- not just initial collection -- is what separates compliant operations from exposed ones.

Another common error is accepting COIs without verifying them against your actual insurance requirements. If your policy mandates $2 million in general liability coverage and a vendor submits a COI showing $1 million, that vendor is non-compliant regardless of whether the certificate "looks right."

The Bottom Line

A COI is your first line of defense against vendor-related liability. Collecting, reviewing, and continuously monitoring certificates is not optional paperwork -- it is a core risk management function. As your portfolio grows, the volume of certificates you manage grows with it, making a systematic approach essential.

In upcoming posts, we will explore the specific coverage types property managers should require, how to set appropriate liability limits, and why manual tracking methods break down at scale.