Economics For Business



Calculate the four-firm concentration ratios for 2006 and 2011. Analyze the industry changes during this five-year period.

Four firm concentration ratio:

For 2006:

10 + 12 + 20 + 21 = 63 %

For 2011:

32 + 29 + 12 + 9 = 82 %

In the year 2006 the four firm concentration ratio indicated an oligopoly market structure and during the 5 years (ending at 2001), these four firms have a captured a bigger market share for themselves. Although firm C maintained the same share and firm E lost a majority of its share. Firm A had the greatest market growth in these ...