With athletes and entertainers so caught up in maintaining the value of their brand, it was only a matter of time before someone started an exchange. Fantex Holdings is a new Wall Street brokerage firm that will give people the opportunity to invest in a star’s future earnings according to an SEC filing released today. The stocks for each celebrity will be launched just like a traditional IPO, and shareholders will be entitled to a cut of the star’s earnings, whether it be from their day job (as an athlete, for example) promotions, movie spots, and so forth. It seems…