What is an additional insured endorsement?

An additional insured endorsement is a modification to your general liability policy that extends coverage to a third party for liability arising out of your operations. When a property management company, general contractor, or municipality requires you to name them as an additional insured, they are asking for more than just proof of insurance — they want your policy to defend and indemnify them if they are sued because of your work.

For example, suppose your crew drops a limb onto a parked car while trimming trees at an apartment complex. The car owner sues both your company and the property management company. If the property manager is named as an additional insured on your general liability policy, your insurer has a duty to defend the property manager and pay any covered damages on their behalf. Without this endorsement, the property manager would have to rely solely on their own insurance, which would then seek reimbursement from you through subrogation.

There are several forms of additional insured endorsements, and the differences matter. The most common for tree service operations are CG 20 10 (ongoing operations only) and CG 20 37 (completed operations only). Many clients require both, often combined on form CG 20 10/37, to ensure coverage extends to claims arising both during and after your work. Some older or broader endorsements like CG 20 26 provide blanket additional insured status for any party you are contractually required to add, which can streamline the process significantly.

Insurers may charge a nominal fee for each additional insured endorsement — typically $25 to $50 per endorsement — though some policies include blanket additional insured coverage at no extra charge. The endorsement does not give the additional insured coverage for their own negligence; it only covers liability arising from your work performed on their behalf.

From a practical standpoint, tree service companies should ask their broker about securing a blanket additional insured endorsement on their policy. This automatically extends additional insured status to any party required by written contract, eliminating the need to request individual endorsements for every client. This is especially valuable for companies that handle high volumes of commercial or municipal work where additional insured requirements are standard.