Waiver of Subrogation

Subrogation is when an insurer, after paying a claim, pursues a third party it believes was at fault to recover the money. A waiver of subrogation endorsement stops the vendor's insurer from doing that to you.

Contracts frequently require it alongside additional-insured status. Like additional insured, it's a checkbox-level detail on the COI that's easy to miss by eye and important to verify.