In construction it is a core risk-transfer tool. An owner is commonly named as an additional insured on the contractor's liability policy, and contractors on the builder's risk policy, so a loss is funded by the responsible party's insurer and subrogation fights are avoided. The exact status (named insured, additional insured, or loss payee) is dictated by the contract and affects who can claim.
How well that protection works depends on the specific endorsement. Some forms cover only liability “caused by” the named insured's work. Others limit coverage to ongoing operations and drop off once the project is complete. Contracts often demand a certificate of insurance plus the actual endorsement. The certificate alone is evidence and does not itself confer coverage. These requirements sit in the insurance provisions. Nonlinear flags additional-insured and endorsement obligations during Spec Takeoff so contractors can line up the right certificates and endorsements before award.
