Since Rupert Murdoch split 21st Century Fox and News Corp into two distinct corporate entities in 2013, the latter's value has halved.

An analysis by Morgan Stanley published this week calculated that the value of News Corp, excluding its stake in the independently run property-marketer REA Group, had fallen from $US7.3 billion ($9.4 billion) in 2013 to $US3.7 billion.

The directly controlled businesses analysed in the report include News Corp's Australian newspapers, The Wall Street Journal, book publisher HarperCollins, and Foxtel.

"The reality is that all of those assets are in the declining phase of their life cycles and falling in value," Morgan Stanley analyst Andrew McLeod wrote.

The reality is that all of those assets are in the declining phase of their life cycles and falling in value

Of course, the separation was brought on by a lack of interest in the print media market from global investors, and the need to distance its sustainable movie and television networks from the bleak future of newspapers in the digital age.

Despite foreseeing tough times, Mr Murdoch remained optimistic because of the introductions of online-newspaper paywalls and global expansion.

"The challenges we face in the publishing and media industries are great, but the opportunities are greater," he said at the time.

Unfortunately for the Australian-born billionaire, Morgan Stanley reports News Corp's newspapers are all shrinking, as are Foxtel and Fox Sports. The only business that is holding firm is book publishing.

Crucially, Mr Murdoch allocated a 62% REA stake to News Corp, Australian Financial Review highlights.

Without the strong performance of REA, News Corp shares would be in free-fall, rather than the 17% decline they have experienced in the last four years.