How Many Firms Should Be Leaders? Beneficial Concentration Revisited
How Many Firms Should Be Leaders? Beneficial Concentration Revisited
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DOI：
10.1111/j.1468-2354.2012.00722.x
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发表时间：
2012-11
期刊：
影响因子：
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通讯作者：
Hiroaki Ino;Toshihiro Matsumura
中科院分区：
文献类型：
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作者：
Hiroaki Ino;Toshihiro Matsumura
我们研究赫芬达尔-赫希曼指数（HHI）和福利之间的关系。首先，我们讨论了m个领导者和N-m个追随者竞争的模型。Daughety（1990）发现，在线性需求和边际成本不变的情况下，Stackelberg模型比古诺模型产生更大的福利和HHI。因此，他证明了有益的集中发生。我们发现，这总是发生在一般的成本和需求函数时，m是足够大的，但并不总是发生时，m是小的。接下来，我们考虑追随者的自由进入，发现无论m如何，有益的集中总是发生。特别是，领导层越是坚持，就越有可能是有益的。
We investigate the relationship between the Herfindahl-Hirschman Index (HHI) and welfare. First, we discuss the model wherein m leaders and N - m followers compete. Daughety (1990) finds that under linear demand and constant marginal cost, the Stackelberg model yields larger welfare and HHI than the Cournot model. Thus, he demonstrates that beneficial concentration occurs. We find that this always occurs under general cost and demand functions when m is sufficiently large, but does not always occur when m is small. Next, we consider the free entry of followers, and find that beneficial concentration always occurs regardless of m. In particular, the more persistent the leadership, the more likely it is to be beneficial.