Question 50

The four-firm concentration ratio is calculated by adding the market shares of the four largest firms.

This ratio provides insight into the level of competition within an industry by measuring the total market share held by the four largest firms.

A) By multiplying the market shares of the four largest firms

This option is incorrect because the calculation of the four-firm concentration ratio does not involve multiplication. Instead, it focuses on the summation of market shares, which indicates the cumulative market control of the largest firms.

B) By adding the squares of the market share of each firm

This option is also incorrect. While adding the squares of market shares is a method used in calculating the Herfindahl-Hirschman Index (HHI) to measure market concentration, it does not apply to the four-firm concentration ratio, which simply adds the market shares directly.

C) By adding the market shares of the four largest firms

This is the correct answer as the four-firm concentration ratio is defined as the sum of the market shares of the four largest firms in an industry. This straightforward addition provides a clear measure of the concentration of market power among the largest firms.

D) By multiplying the squares of the market share of each firm

This option is incorrect as it misrepresents the method for calculating the four-firm concentration ratio. Multiplication of squares is not relevant in this context, as the focus is solely on the addition of market shares.

Conclusion

The correct method for calculating the four-firm concentration ratio is to add the market shares of the four largest firms, which effectively indicates the concentration of market power. All other options either misinterpret the calculation method or apply unrelated concepts, thus reinforcing the validity of the correct answer.