Phelps, who now holds the record for the most number of gold medals won in a single Olympics, received a $1 million bonus from chief sponsors Speedo, but it expected to earn between $50 million and $100 million in future endorsements and sponsorship.
His financial advisers are putting together a property portfolio as part of a larger investment plan and it is clear he will be able to take advantage of tumbling property prices in the US market.
He has already bought a luxury $1.7 million apartment in his home town of Baltimore. Overlooking the city's waterfront it has a jacuzzi and, of course, a swimming pool. The apartment also has a roof terrace, a screening room, a whirpool tub and a gym.
Phelps has also invested in commercial property and bought a swimming club and ice rink in Baltimore. He and his coach, Bow Bowman, want to turn the Meadowbrook Swim Club and Northwest Ice Rink into an elite Olympic training facility.
According to his agent, Peter Carlisle, he earned $3 million a year in endorsements before the Olympics but his new found status means he can earn much more.
'This is a terrific opportunity for a young man. If he gets the best advice he will never have to worry about an income again. Of course property is going to be part of his investment future,' said Thaddeus Shelly, senior managing director of Bessemer Trust, a leading investment house.
Phelps was praised for buying in his home town rather than seeking some kind of celebrity pad in Los Angeles or New York. 'He would seem to be a young man who is getting excellent advice. He might even help revive the property market in Baltimore,' said Shad Stevens of Property Now, consultants in the city.
He refused to say if Phelps bought his property at a 'bargain' price. But average property prices have fallen by 5% since the peak in buying three years ago in Baltimore.
