AT&T

CEO: Randall Stephenson

Dec. 30, 2016: $42.53

March 31, 2017: $41.55

Change: -2.30%

On Oct. 22 AT&T announced an agreement to buy global entertainment and media powerhouse Time Warner for $85.4 billion in cash and stock. The acquisition, which AT&T hopes to close this year, is part of a broader trend among telecommunications carriers to add content to their offerings – Verizon's deal to acquire Yahoo being another example. 

In January AT&T reported that revenue for all of 2016 was $163.79 billion, up 11.5 percent from $146.80 billion in 2015. But operating income in 2016 was $24.35 billion, down nearly 2 percent from $24.79 billion in 2015.