Lebron has been linked to the Fenway Sports Group (FSG) for quite a while now. They own the Red Sox, Liverpool FC, both stadiums and other sports investments. I'm thinking the official announcement just means Lebron invested more, which got him enough to be recognized as an official partner (owner level) in the ownership group. I guess my point is that it's not new, and it started in 2011. FYII am still adjusting to the fact that Lebron owns part of my beloved Red Sox. Both of these transaction are weird but hey now I think the Jazz are cooler. Red Sox were always cool. lol.
BBC link