In its most basic form an additional insured endorsement is a part of your insurance policy that identifies a specific third party as being covered by your insurance for claims against them that you cause. People who request an additional insured endorsement want you to pay for insurance that covers them. Initially that seems fair and uncomplicated. However third parties often demand additional advantage which make it more complicated and expensive and perhaps unfair to you. Find out how other people increase your insurance costs and what to do about it.