Generally speaking, when the Herfindahl-Hi

问题单项选择题

Generally speaking, when the Herfindahl-Hirschman Index (HHI) is calculated by summing the squared percentage market shares, how many largest firms data is used in a industry, supposing there is a large number of firms in the industry:（）

A．4

B．10

C．50

答案

参考答案：C

解析：

The Heffindahl-Hirschman Index (HHI) is calculated by summing the squared percentage market shares of the 50 largest firms in an industry (or all of the firms in the industry if there are less than 50). The HHI is very low in a highly competitive industry and increases to 10000 (=1002) for an industry with only one firm. An HHI between 1000 and 1800 is considered moderately competitive, while an HHI greater than 1800 indicates a market that is not competitive.