Does an industry go to monopoly when there is no policy control? Supposing there are only a dominant firm and a competitive fringe in an industry with constant returns of scale, which play Stackelberg game, we analyze the industry concentration change if the dominant firm is permitted to acquire the competitive fringe. It is showed that the industry will be in monopoly if there is no investment, or not enough investment of the fringe.

• 夏同水(山东师范大学商学院) | Xia, Tongshui
• 张延华(青岛开发区工委党校) | Zhang, Yanhua