Answer :
The four-firm concentration ratio is a measure of market concentration indicating that the four largest firms in an industry account for 84 percent of the total sales in the industry.
When we refer to the four-firm concentration ratio, we are looking at a measure that indicates the extent of market concentration and monopoly power within an industry. It specifically measures the combined market share of the industry's four largest firms with respect to total sales.
Therefore, if the four-firm concentration ratio for an industry is 84 percent, it means that the four largest firms in the industry account for 84 percent of the industry's total sales. This indicates high market concentration and could suggest a situation that is closer to oligopoly or monopoly, which may result in market inefficiencies.
