Purchasing Fox, which owns TV channels like FX and movie franchises like "Avatar" and "X-Men," is a way to scale up. Comcast was in talks to buy Fox late last year. But it lost out to Disney in part because major Fox investors weren't sure the proposal would win over government regulators. Around the same time, the Justice Department sued to block the AT&T-Time Warner deal. Both deals share similarities: AT&T and Comcast are distributors trying to buy content creators. Comcast re-entered the picture last month when it said publicly that it was preparing a bid for Fox. Related: War of the media moguls: Is Brian Roberts outflanking Bob Iger? Brian Roberts, the CEO of Comcast, is known as a tenacious dealmaker. One of his direct reports, NBCUniversal CEO Steve Burke, told the Los Angeles Times: "Brian never gives up. We have worked on a lot of deals together and he just out-hustles everyone. He's a very persistent guy."