In construction it's 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 materially affects who can claim.
How well that protection actually works depends on the specific endorsement: some forms cover only liability “caused by” the named insured's work, while 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, since the certificate alone is just evidence and doesn't itself confer coverage. Since these requirements are buried in the insurance provisions, Nonlinear flags additional-insured and endorsement obligations during Spec Takeoff, letting contractors line up the right certificates and endorsements before award.
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