For half a billion dollars, the world's sixth richest man buys paradise isle

You probably would too if you had $36bn [£23bn]. Not content with a vast collection of toys that includes luxury homes, private jets, lavish cars and cup-winning sailboats, the software mogul Larry Ellison is splashing out on his own paradise island.

The American founder of Oracle is buying Hawaii's sixth-largest island, Lanai, for a price estimated at about half a billion dollars – putting Britain's Richard Branson to shame, since his Caribbean idyll, Necker Island, is worth barely one-fifth of that.

What Mr Ellison gets for his money is 141 square miles of barely-developed natural beauty, a property that has been nicknamed Pineapple Island because of its history of plantations.

These days it is a luxury resort, accessible to the billionaire set by helicopter or private jet. It boasts championship golf courses, opulent hotel resorts, and 47 miles of coastline that includes some of the most pristine beaches in the US. There are barely 3,000 residents, and few of the roads are paved.

Microsoft founder Bill Gates – one of only two Americans richer than Mr Ellison – married his wife Melinda there, and he had been rumoured as a potential buyer himself when the island went up for sale at a price tag of between $500m and $600m.

The previous owner, billionaire David Murdock, who transformed Lanai from agricultural centre to a hang-out for the rich and famous, predicted Mr Ellison "will bring a new and fresh perspective to the island and its people," though his plans remain a mystery. Mr Murdock is keeping a two per cent sliver of the island.

"It is my understanding that Mr Ellison has had a long-standing interest in Lanai," Hawaii's governor, Neil Abercrombie, said, confirming the sale.

For the four-times divorced Mr Ellison, Lanai is the biggest and most expensive in a series of lavish purchases since he shot to the top echelon of the world's rich lists. Forbes, the business magazine, ranks him as No 6 in the world, and Oracle – which he started as an experimental database software company in 1977 – now has its tentacles in almost every aspect of corporate IT.

Ultra-competitive in sport and business, Mr Ellison lavished an estimated $100m on his plan to win the America's Cup, which he did in 2010 with a 90ft trimaran called the BMW Oracle. His garages are stuffed with cars, including a McLaren Formula One vehicle. Two years ago he rescued the US Open tennis tournament, and now owns a 50 per cent stake in the event.