The information is more comprehensive than most observers expected and has led to claims that mergers will get caught up in red tape.
Newspaper groups looking to merge would have to provide Ofcom with details of the number of column inches devoted to sport, human interest stories and regional stories.
They would also need to supply the employment history of the acquiring owner and policies relating to reporting techniques and journalism standards. Such scrutiny will come into play should Richard Desmond's Express Newspapers attempt to buy The Daily Telegraph.
The information Ofcom requires to investigate a possible takeover of ITV or five is equally stringent and has a particular focus of protecting ITV's regional strengths.
In radio, Ofcom will ask for data for the acquiring and acquired broadcaster showing details of the hours of automated programming, syndicated programming and the hours of local news provided.