The writers of Warner Bros.’ “Mystic River” and Universal’s “Seabiscuit” tied as winners of the 16th annual Scripter Award for best adapted film, marking the first time two movies have shared the nod.

The films tied last week in the initial Scripter selection committee balloting, then tied again in a runoff vote.

“Support for both films was incredibly strong and, in the end, the committee could not eliminate either of these worthy contenders,” said Robert Towne, who chairs the committee. “This unprecedented finish is a fitting end to a year with so many outstanding film adaptations.”

The other finalists for the Scripter Award were author Charles Frazier and screenwriter Anthony Minghella for “Cold Mountain”; author J.R.R. Tolkien and screenwriters Frances Walsh, Philippa Boyens and Peter Jackson for “The Lord of the Rings: The Return of the King”; and author Patrick O’Brian and screenwriters Peter Weir and John Collee for “Master and Commander: The Far Side of the World.”

The annual Scripter gala will be held Feb. 15 on the USC campus to honor author Dennis Lehane and screenwriter Brian Helgeland for “Mystic River” along with author Laura Hillenbrand and screenwriter Gary Ross for “Seabiscuit.” Sharon Gless will emcee.

Helgeland and Ross were also tapped Thursday by the WGA as nominees for its adapted screenplay prize. Helgeland won the Scripter, the WGA award and the Oscar in 1998 for “L.A. Confidential,” sharing the kudos with Curtis Hanson; Ross was previously nominated for WGA and Oscar screenwriting noms for “Big” and “Dave.”

Past Scripter winners include the authors and screenwriters of “The Hours,” “A Beautiful Mind,” “Wonder Boys,” “A Civil Action,” “The English Patient,” “Sense and Sensibility,” “The Shawshank Redemption” and “Schindler’s List.”