Microeconomics 6th Edition by Robert Hall, Shirley Kuiper, Marc Lieberman

Exercise 16

In September 2011,the U.S. government announced that it would go to court to block AT T's planned acquisition of T-Mobile. At the time,the market shares of the four largest wireless carriers (which together had about 90% of the market)were roughly as follows:
Verizon 33%
AT T 31%
Sprint 16%
T-Mobile 10%
a. Ignoring the other small wireless firms not shown,what was the value of the HHI before the planned acquisition?
b. What would be the value of the HHI be if the proposed acquisition were completed?
c. Was the U.S. government's opposition to the merger consistent with its 2010 guidelines? Explain briefly.