Island Def Jam Music Group has acquired the 50% it did not already own in Roc-A-Fella, its joint venture with Jay-Z, Damon Dash and Kareem "Biggs" Burke. Additionally, as expected, Jay-Z has been name

Island Def Jam Music Group has acquired the 50% it did not already own in Roc-A-Fella, its joint venture with Jay-Z, Damon Dash and Kareem "Biggs" Burke. Additionally, as expected, Jay-Z has been named president/CEO of Def Jam Recordings.

Jay-Z (real name Shawn Carter) will continue to run Roc-A-Fella, which first entered into a joint venture with Def Jam in 1997. IDJ's acquisition of the label does not include the Roca Wear clothing line, 40/40 nightclub and other related businesses.

Based in IDJ's New York offices, Jay-Z will officially take his Def Jam post Jan. 3. In his new role, he will report directly to Antonio "L.A." Reid, chairman of the Island Def Jam Music Group.

Def Jam's last president, Kevin Liles, left in July to join Warner Music Group as executive VP.

Jay-Z announced his "retirement" as an artist after the release of last year's "The Black Album" (Roc-A-Fella/Def Jam), which debuted at No. 1 on The Billboard 200. Retirement has not come easy for the superstar: His collaboration with Linkin Park "MTV Ultimate Mash-Ups Presents Jay-Z/Linkin Park: Collision Course" (Warner Bros.) debuts at No. 1 on The Billboard 200 this week.

"After ten years of successfully running Roc-A-Fella, Shawn has proven himself to be an astute businessman, in addition to the brilliant artistic talent that the world sees and hears," says Reid in a statement. "We are fortunate that he has agreed to take over as president and CEO of Def Jam Recordings. I can think of no one more relevant and credible in the hip-hop community to build upon Def Jam's fantastic legacy and move the company into its next groundbreaking era."