Property-liability insurance is distributed by two different types of firms, those that distribute their product through independent agents, who represent more than one insurer,and direct writing insurers that distribute insurance through exclusive agents, who represent only one insurer. This paper analyzes the reasons for the long term coexistence of the independent agency and direct writing distribution systems. Two primary hypotheses explain the coexistence of independent and exclusive agents. The market imperfections hypothesis suggests that firms that use independent agents survive while providing essentially the same service as firms using exclusive agents because of market imperfections such as price regulation, slow diffusion of information in insurance markets, or search costs that permit inefficient firms to survive alongside efficient firms. Efficient firms are expected to earn super-normal risk-adjusted profits, while inefficient firms will earn risk-adjusted profits closer to normal levels. The product quality hypothesis suggests that higher costs of independent agents represent unobserved differences in product quality or service intensity, such as the providing of additional customer assistance with claims settlement,offering a greater variety of product choice sand reducing policyholder search costs. This hypothesis predicts normal risk-adjusted profits for both independent and exclusive agency firms. Because product quality in insurance is essentially unobserved, researchers have been unable to reach consensus on whether the market imperfections hypothesis or the product quality hypothesis is more consistent with the observed cost data. This lack of consensus leaves open the economic question of whether the market works well in solving the problem of minimizing product distribution costs and leaves unresolved the policy issue of whether marketing costs in property-liability insurance are excessive and perhaps should receive regulatory attention. The