Sunk Costs, Accommodation, and the Welfare Effects of Entry.

Although economists usually support the unrestricted entry of firms into an industry, entry may lower social welfare if there are setup costs or if entrants have a cost disadvantage. The authors consider the welfare effects of entry within a standard Cournot model where some of an incumbent firm's costs are sunk. They find that the range of parameter values over which entry can harm welfare declines monotonically in the fraction of costs that are sunk. Furthermore, the presence of even a small fraction of sunk costs often reverses an assessment that entry harms welfare. Copyright 1998 by Blackwell Publishing Ltd