Comcast may seal a deal to buy a controlling stake in NBC Universal from General Electric by next Monday, people familiar with the matter say, creating one of America’s largest media companies.

The deal, which values NBC Universal at about $30bn, would give Comcast, the top US cable operator, a 51 per cent stake in a joint venture that would combine its small roster of cable channels with America’s oldest broadcast network and some of the media’s largest cable networks.