discussed recently). Lyrics are separately copyrightable and if the company is borrowing too much from the originals, they would create an infringing derivative.
Are these parodies or fair use? We doubt whether the changed lyrics qualify as fair use/parody. Most judges believe that a parody of a song makes fun of the underlying subject matter (although one judge claimed a parody doesn't even have to involve humor). In any case, if the use is commercial, and the company is recording or performing the complete song, this would be a hard sell as a fair use defense. In addition, the Fortune 50 classification and the accompanying deep pockets also make the company an appealing target ... should the song owners learn of the infringement.
By the way Dept. Permission is not required from the original artists; it's required from the owners of the song copyright (usually a music publisher).