The green light from the Justice Department makes it more difficult for Comcast to mount a competitive counteroffer. The cable giant, which also owns NBCUniversal, will have to raise even more cash, adding to its debt, and convince Fox’s board that it, too, would gain government approval. Comcast, which already controls nine regional sports networks, has signaled that it would also be willing to sell Fox’s regional sports networks.

Fox has not yet set a date for its shareholders to vote on the Disney deal.

Fox’s Prized Assets

At stake are cable channels including FX and National Geographic, the “Avatar” and “X-Men” film franchises, and a pair of international television networks: the European pay-TV operator Sky and Star India. Those two networks, which are growing businesses with an emphasis on streaming services, are key attractions for both Disney and Comcast. In addition, the winner gets control of the streaming service Hulu, which has more than 20 million customers.

Gobbling up Fox would significantly increase Disney’s already formidable box office business. In 2017, the two controlled a combined 35 percent of the box office in North America. This year, they control 50 percent. Three of Hollywood’s most successful film studios are owned by Disney: Marvel Entertainment, Pixar and Lucasfilm.

Not included in the sale are Fox News, the Fox broadcasting stations and the FS1 sports network.

The regional sports networks are one of Fox’s most valuable businesses and are expected to generate more than $2 billion in profit this year. Adding those channels to Disney’s portfolio could be seen as stifling competition since Disney also controls ESPN, the dominant cable sports channel in the United States. The sports networks could also be problematic for Comcast because of the regional networks it already owns.

A Quick Go-Ahead

The Justice Department approved the Disney deal just six months after the merger was announced. Transactions of this size typically take a year or longer. The relatively quick process contrasts markedly with AT&T’s $85.4 billion purchase of Time Warner, which took almost two years to close. The Justice Department had sued to block that deal but lost the case this month after it failed to convince a federal judge that combining the companies would lead to higher cable bills.