Sky Global is being downsized so that General Motors, which owns DirecTV via its Hughes Electronics subsidiary, is not faced with large tax charges on completion of the deal.
As part of the overhaul, Sky Global will lose its stake in NDS, the digital TV software firm, and around half its stake in electronic programming guide Gemstar TV Guide. These interests will, however, remain part of News Corp.
Sky Global has already disposed of its stake in its loss-making Italian pay-TV operation Stream in a bid to sweeten Hughes shareholders who were initially opposed to the deal.
Murdoch needs to ensure that Hughes shareholders are left with at least 51% of the merged company if GM is to avoid a huge tax bill.
Once DirecTV is merged with Sky Global Networks it will create an independent publicly listed company with a value of around $70bn (£47.9bn). News Corp is expected to take a 34% stake in the company and retain day-to-day operating control.
GM had initially been expected to realise around $6bn (£4.3bn) in cash from the sale that could be used to strengthen its balance sheet, avoiding a credit downgrade which would mean higher borrowing costs.
Murdoch's strategic investors in the DirecTV deal -- Microsoft and Liberty Media -- have agreed to inject a total of around $4bn (£2.9bn) into the transaction -- $3bn (£2.2bn) and £1bn (£717.9m) respectively.
General Motors would also expect to reap some cash if Murdoch decides to sell Hughes' satellite subsidiary PanAmSat.
The News Corp negotiations are not out of the woods yet and could still face a counter-bid from EchoStar, the US's second-largest satellite TV provider and operator of the Dish Network.
GM CEO Rick Wagoner said that, although negotiations were continuing with News Corp, the car giant would still be open to better offers.
Referring to a bid by DirecTV rival EchoStar, Wagoner said, "What we're willing to say is that if they come up with a bona fide offer then we will gladly consider it."