Should a retailer sell its own extended warranties or resell those from the manufacturer when confronting supplier encroachment?

Due to fierce competition in the product market under conditions of supplier encroachment, many brand name retailers, including Sears, Best Buy, and Circuit City, depend on the extended warranty contracts that they sell along with the products. The distribution of extended warranties through an intermediary can be characterized in terms of two basic forms. A large proportion of retailers sell their own extended warranty, whilst others choose to...