IBM Corp. asked a federal judge to throw out The SCO Group Inc.’s $5 billion lawsuit, arguing the Utah company failed to show its intellectual property was misappropriated when Big Blue donated software code to the freely distributed Linux operating system. SCO shares tumbled just short of a 52-week low.

IBM filed six motions asking U.S. District Judge Dale Kimball and Magistrate Brooke Wells to toss out the claims remaining after Wells struck down most of SCO’s case months ago.