An unauthorized biography of Jay-Z suggests that the rap impresario may not have paid full price for his interest in the Nets.

Zach O'Malley Greenburg, a Forbes writer, says the disparity between reports of what he paid for his 1.47% interest in the team (and arena) and what it's worth can be explained by a celebrity discount. Jay-Z, according to one report, paid $1 million for his interest but another says it's worth $4.5 million.

"Empire State of Mind" also reports that the idea for Jay-Z's investment was first raised, as a joke, by Jason Kidd.