Comcast-Time Warner Cable deal to face antitrust probe
The US Department of Justice has launched an antitrust probe of Comcast's proposed acquisition of Time Warner Cable.
The $45bn (£27bn) deal would see the largest cable companies in the US join forces.
The two companies are also two of the largest broadband providers in the US.
Comcast has argued that the two companies serve different markets, and their combination will not reduce competition for consumers.
US regulators are expected to closely scrutinise the proposed purchase by Comcast, owner of the NBC television network and Universal Studios.
The probe will be overseen by two Justice Department officials - Principal Deputy Assistant Attorney General Renata Hesse and Deputy Assistant Attorney General David Gelfand.
Comcast operates mainly around Washington DC, Chicago, Boston and its home town of Philadelphia.
Time Warner Cable's subscribers are mainly grouped around its New York headquarters, Los Angeles, Milwaukee, and Dallas.
The new Comcast-Time Warner Cable group would have competition in those areas from rivals including AT&T and Verizon.
The deal would allow Comcast to control three quarters of the US cable industry with around 30 million subscribers.
As well as the DoJ investigation, the deal is also to be reviewed by the Federal Communications Commission.