Rebecca Black’s parents paid Ark Music Factory to make their daughter, Rebecca Black, a professional-looking music video. At first it was just a video for her friends and family to watch, and then it went viral. When it went viral, Ark Music Factory started getting at the Black’s over who owned the copyright of the song, since it was making lots of money for the Black’s. The brief summary is that Jey and Wilson held the original rights to the composition, while Black probably holds the copyright on the recording itself (though, there may be some questions about the musicians who played on the track). The Rolling Stone Report on it says that "the agreement that she signed with Ark in November stipulates that Black has 100 percent ownership and control of 'Friday,' including the master recording and the music video." Of course, that probably includes the copyright on the composition, but it might not, if the contract isn't explicit. Who owns the master recording and the video is meaningless to the copyright question. If the contract only focuses on that, then Jey and Wilson conceivably could still hold the copyright on the composition.
http://www.techdirt.com/articles/20110406/00514213794/copyright-fight-ensues-over-rebecca-blacks-friday.shtml
