As far as I know, there is only 1 black owner in any of the 4 major sports - Robert Johnson who a principal owner of the Charlotte Bobcats, and this has only been since 2002. Incidentally, Johnson is also the first black American billionaire - he founded the BET network. Once again, it takes tremendous financial resources to own a team - you can't be rich, you have to be wealthy.
As Chris Rock says, "Shaq is rich. The white guy who signs Shaq's check is wealthy".