It's common knowledge that the popular music industry is dominated by a few huge companies, sometimes referred to as the Big Three: Universal Music Group, Sony Music Entertainment and Warner Music Group. It used to be the Big Four, until EMI was subsumed into the other three. Before that, it was the Big Five, which followed the Big Six, etc. As time has gone on, the music market has becoming more and more restrictive in the choices you can actually make as a consumer. According to Nielson SoundScan, these three companies controlled roughly 90 percent of the music market in 2012, and this is a number trending upward. The problem for rap fans, though, is even more severe.