* Disney seals much-awaited deal to buy Fox assets
* Disney CEO Bob Iger extends tenure to oversee integration
* Fox to spin off news, sports and business TV assets first
* Shares of both companies lower (Adds deal details, background, byline, Iger quote)
Dec 14 (Reuters) - Walt Disney Co has struck a deal to buy film, television and international businesses from Rupert Murdoch's Twenty-First Century Fox Inc for $52.4 billion in stock as the world's largest entertainment company seeks even greater scale to combat growing digital rivals Netflix Inc and Amazon.com Inc.
The deal brings to a close more than half a century of expansion by Murdoch, 86, who turned a single Australian newspaper he inherited from his father at the age of 21 into one of the world's most important global news and film conglomerates.
Shares of Fox fell more than 2 percent in premarket trading. Disney shares also edged lower.
Under the deal, Disney acquires significant assets from Fox, including the studios that produce the blockbuster Marvel superhero pictures and the "Avatar" franchise, as well as hit TV shows such as "The Simpsons."
Fox stockholders will receive 0.2745 Disney shares for each share held and will end up owning about a quarter of Disney.
Disneys global footprint also expands with the acquisition of Fox's international satellite assets, including Star TV network in India and a stake in European pay-TV provider Sky Plc .
The acquisition will give Disney a new pipeline of shows and movies as it battles technology companies spending billions of dollars on programming shown online to siphon audiences away from traditional TV networks.
Immediately before the acquisition, Fox will separate the Fox Broadcasting network and stations, Fox News Channel, Fox Business Network, FS1, FS2 and the Big Ten Network into a newly listed company that it will spin off to its shareholders.
Disney Chief Executive Bob Iger, 66, will extend his tenure through the end of 2021 to oversee the integration of the Fox businesses. He has already postponed his retirement from Disney three times, saying in March he was committed to leaving the company in July 2019.
"This gives us the ability to marry the great content of Fox with the great content of Disney, it gives us a much larger international footprint, and it enables us to use cutting-edge technology to reach consumers in far more compelling ways," Iger told ABC's "Good Morning America" program.
Iger said new technology would be necessary to meet the demands of viewers who want to access content anytime. Direct-to-consumer service is a top company priority, he added.
Disney will also assume about $13.7 billion of Fox's net debt in the deal.
Through Fox's stake in the Hulu video streaming service, Disney would assume majority control of one of Netflix Inc's main competitors. Hulu is also partially owned by Comcast Corp and Time Warner Inc.
(Additional reporting by Susan Heavey in Washington; reporting by Aishwarya Venugopal in Bengaluru; Editing by Patrick Graham and Lisa Von Ahn)