Rumor has it, 'The Hobbit: Into the Fire' has been registered for the third installment which is currently titled 'The Hobbit: There and Back Again'.
"The Hobbit: There and Back Again" may get retitled. According to The One Ring, New Line has registered a new title, "The Hobbit: Into the Fire", for the upcoming third and last installment of Peter Jackson's Hobbit trilogy. It's a reference to a chapter title in J.R.R. Tolkien's book.
The Hobbit solo adventure was initially planned to be turned into two movies with "The Hobbit: An Unexpected Journey" coming first before "There and Back Again". When the decision for trilogy was made, they decided to keep those titles for the first and third entries and give a new title, "The Hobbit: The Desolation of Smaug", to the second movie.
The third film is due December 17 this year. It concludes the adventure of the title character Bilbo Baggins, who joins the Wizard Gandalf and thirteen Dwarves, led by Thorin Oakenshield, on an epic quest to reclaim the lost Dwarf Kingdom of Erebor.