Zenimax Media recently filed a trademark for Oblivion during August. Specifically, the trademark for the Bethsoft parent company covers motion picture film production; entertainment services, namely, providing motion picture theatrical films in the field of fantasy games.
Now it could just be that Zenimax is covering all of its bases and making sure that nobody makes a Oblivion movie under their noses. Or they could be looking to make a movie in the style of the Elder Scrolls and help expand the franchise.
Source: VGTribute.com
