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The AT&T-Time Warner ruling is making the Murdoch family billions of dollars richer

Alex Sherman

In December, Rupert Murdoch decided a $52 billion offer from Disney fairly valued his bundle of Fox assets. Now he's staring at a bid that's almost $20 billion higher.

On Wednesday, Disney increased its cash and stock proposal to $71.3 billion. That's because Judge Richard Leon's decision last week to allow AT&T to buy Time Warner without conditions encouraged Comcast to offer $65 billion for the Fox assets (a move it considered for months ), topping Disney's bid. And it led Disney to hit right back.

Many media companies were rooting for the Time Warner deal to be approved because removing the regulatory concerns around big deals unlocks potential buyers. Verizon , Charter, Comcast and AT&T now have the flexibility to buy content companies without nearly as much fear that their deals will be blocked.

Shares of Discovery, Lionsgate, AMC, CBS and Viacom are all up since Judge Leon's ruling as investors circle potential targets, knowing that whoever is the losing bidder for Fox's assets could conceivably look to acquire a different content company.

But don't expect Comcast to just walk away from Disney's latest offer. Comcast is fully prepared for a bidding war and expected Disney to increase its bid, even if the amount of cash Disney added to the offer (50 percent) may have come as a bit of a surprise. Comcast is now deliberating its next move.

This could go on for a while, and it's all good news for Fox shareholders as well as other investors in the space hungry for returns.

Disclosure: Comcast is the parent company of NBCUniversal and CNBC.