Post 200 The guide to the region's top businesses

AT&T's Corporate Center in Chicago. (Scott Olson/Getty Images)

Major employers

AT&T

The largest communications company in the country announced plans in March to get even bigger by buying T-Mobile USA from Deutsche Telekom in a $39 billion deal. The acquisition would add over 33 million customers and give AT&T more than 40 percent of the mobile phone market, making it significantly larger than main rival Verizon. But in August, the Justice Department sued to block the deal, saying it would leave consumers with fewer choices and higher costs for mobile phone service.

Trivia

AT&T traces its roots to 1876, when Alexander Graham Bell invented the telephone.