The Walt Disney Company has resumed talks with 21st Century Fox about buying at least part of the company, as Fox weighs whether to shrink its empire, two people briefed on the matter said on Saturday.

Fox is still in talks with Comcast about a potential deal, added these people, who were not authorized to speak publicly about the negotiations. The Murdochs, who control Fox, are expected to make a decision about whether to pursue a sale by the end of the year, one person added.

The return of Disney, which held talks with Fox earlier this year, highlights how media companies are increasingly seeking to compete in a new era of streaming by getting bigger and acquiring more content. It also leaves medium-sized players like Fox to decide whether they can buy the scale they need — or sell and focus on particular business niches.

If Fox decides to pursue sales negotiations, it would represent a potential unwinding of a media kingdom that the Murdoch family has assembled for decades. Disney and Comcast have been most interested in only part of the constellation of Fox businesses, notably the 20th Century Fox movie studio; cable channels like FX; Sky, the British broadcaster; Star, an Indian broadcaster.