Consider an Industry That Is Made Up of Nine Firms

Multiple Choice

Consider an industry that is made up of nine firms, each with a market share (per cent of sales) as follows:
a.Firm A: 30%
b.Firm B: 20%
c.Firms C, D and E: 10% each
d.Firms F, G, H and J: 5% each
What is the value of the four-firm concentration ratio and how is the industry categorised?

A) 50%; monopolistic competition
B) 70%; oligopoly
C) 75%; oligopoly
D) 80%; strongly oligopolistic