Regulators probing BSkyB's stake in ITV will include Rupert Murdoch owned UK papers such as The Sun in its study.
ITV's is the UK's leading commercial broadcaster
The Competition Commisision will decide whether the 17.9% stake, allied to Mr Murdoch's other UK media interests, threatens diversity of news.
It will seek to establish if there is an "ownership link" between BSkyB, News International, publisher of The Sun, ITV and broadcast news provider ITN.
Rival broadcasters claim BSkyB's stake harms competition but it denies this.
As well as owning the Sun, the Times, Sunday Times and News of the World, Mr Murdoch's News Corporation is the largest shareholder in BSkyB.
At the time BSkyB bought the stake last November, rival Virgin Media was seeking a potential merger with ITV.
Critics claimed that BSkyB's move was aimed at preventing such an outcome but BSkyB said it was investing in an undervalued company with significant growth potential.
Ministers referred BSkyB's stake to the Competition Commission in May after the Office of Fair Trading said the situation cast doubt on ITV's independence.
Outlining details of the terms of its investigation, the Commission said it would examine what impact BSkyB's financial interest in ITV would have on media competition in general and, in particular, the provision of TV news.
It will seek to establish whether the situation affects the plurality of news suppliers providing coverage to different audiences across the UK.
Under particular scrutiny will be ITV's 40% stake in ITN, which supplies news to ITV and Channel 4, and whether BSkyB may be able to influence ITN's editorial approach, strategy or funding through its involvement with ITV.
If it finds that the current situation is against the public interest, the Commission could potentially recommend to ministers that BSkyB be forced to sell the stake.
The investigation, during which BSkyB and ITV executives will appear before Commission officials, is expected to take at least six months.