Suppose that the top six firms in an industry have total annual sales of $70 billion, $40 billion, $30 billion, $30 billion, $20 billion, and
$10 billion, respectively.
Instructions: Enter your answers as a whole number.
a. What is the four-firm concentration ratio for this industry?
70 percent
b. What is the Herfindahl index for this industry? Hint: To find the Herfindahl index, you will need to compute the percentage market
share for each firm in the industry.