Benson will be allowed to own both an NBA and NFL franchise because the two squads are in the same market.
NBA Commissioner David Stern, who has called Benson "a firm believer in investing in New Orleans," first announced the sale in April -- less than two years after the league bought the Hornets from George Shinn for a reported $318 million.
Benson reported to be paying $338 million for the team.
The sale comes at a time when the Saints are under fire from the NFL for instituting a "bounty" program in which players were paid for injuring opponents.
The Hornets won the NBA Draft lottery last month and are expected to take star Kentucky freshman Anthony Davis with the top overall pick.