In a successive Cournot oligopoly, we show the welfare effects of entry in the final goods market with no scale economies but with cost difference between the firms. If the input market is very concentrated, entry in the final goods market always increases welfare. If the input market is...

Common wisdom suggests that entry reduces profits of the incumbent firms. On the contrary, we show that if the incumbents differ in marginal costs and the entrants behave like Stackelberg followers, entry may benefit the incumbents who are relatively cost efficient while it always hurts the cost...