I'm sure he has been mentioned, but Lennox Lewis is worth a fortune still. Also, I believe I heard that Gerry Cooney lives a comfortable life as well. Not rich, but very comfortable. Didn't Bruce Seldon invest his money in some sort of pension plan that pays him $30,000 a year for life or something like that? $30k combined with whatever income he earns on top of that could make for a comfortable living.
Interstingly, the South African heavies did well----Sanders did very very well. So did Knoetze and DuPlooy.
Unfortunately for Michael Spinks, he made $24 million in his career and just gave it all to Butch Lewis to "manage" for him. Lewis paid for Spinks' home. Paid Spinks' bills. And Lewis sent Spinks a check for $6,000 a month for spending money. Michael was happy with the arrangement. He lived a pretty normal life after boxing. When Lewis died, Spinks was notified that Lewis had basically just pooled his money in with Butch's money, and there were no separate accounts. It was all Butch's money. And Spinks wasn't included in Butch's will. So Butch's girlfriend hired a former judge and head of Black Entertainment Television to represent her and stopped all payments to Spinks. That was nine years ago. Don't know how he's doing now.
Apparently retired with £20M and put half into property abroad around 2006/7, which tanked with the recession. Read that in an old Boxing News/Monthly.