Managerial Economics & Business Strategy 7th Edition by Michael Baye, Stanley Brue, David MacPherson

Exercise 1

Ten firms compete in a market to sell product X. The total sales of all firms selling the product are $1 million. Ranking the firms' sales from highest to lowest, we find the top four firms' sales to be $175,000, $150,000, $125,000, and $100,000, respectively. Calculate the four-firm concentration ratio in the market for product X.